Allison 5 speed TCM common issues and fix Allison 1000 

My son has a 2003 2500 silverado with an Allison transmission. When he was 1200 miles away from home on a job assignment the transmission all of a sudden wouldn't shift out of 1st. He had it towed to a transmission shop that had an Allison technician. They pulled codes and determined it needed a $4200 rebuilt transmission replacement. I used to be an ASE Master technician and I just couldn't believe that at 80k miles the trans was toast. So I researched the trans and came across this video. I instructed my son at to what to do and where to look. After repositioning and cleaning the plug contact pins the transmission worked flawless. Thank you so much for this video!

I have a 03 Chevy Silverado k2500. It out of nowhere stopped shifting out of 1st, speed gauge stopped working, temp gauge stopped working and so did the rpm’s gauge and had abs and parking light on and engine light. We went and changed the abs speed sensor which did not fix the problem, and then was led by people to think it was a instrument cluster. Changed out the instrument cluster, did nothing. I ran the codes on my truck and found it reading a ton of different codes but the main one being the transmission control module. I really did not want to have to buy that with how expensive it is and how expensive the cluster was but I came across this video and went out and sure as heck, one was completely unplugged!!!!! You saved me time, money, and a headache. The truck works perfect now all the gauges are reading right. And lucky me, I found the video in time and fixed it so I still have 30 days to return the instrument cluster and get my money back!!!!!

Thanks Spartans. Two pins in my TCM connector, were pushed back. Just pulled them forward and tacked them with a spot of epoxy, on the under side of the pin. Now the transmission shifts like butter. Before the fix my 2001 GMC 2500hd 8.1L , would have to rev high to get out of first gear, then would not shift out of second gear. I had taken the TCM off to perform some maintenance, that's when they got pushed back.

I have to thank you immensely for this video. Saved me money and time with the dealership. Had to remove the TCU to get to water pump and it must've been enough to back the last pin on the red harness. If you were local, I'd buy you a beer!

Omg five shops and 2000 later this fixed my 708 code with me doing in ten mins. Cant believe not one shop knew this and seeing so many others with same issue. Please add more to title so others can find when looking up tcm problems

I was just about to replace my TCM 5 speed and I will check this first. Thank you thank you. God bless you.

Great video. I got the Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner and used it on both male and female sides. Took an old tooth brush and rag to the connectors then let dry. Put it together and cleared the trans trouble code(s). Took it for a long drive and tested for codes along the way and this morning. Codes gone problem solved after years of living with the one none critical code. Thank you for sharing your knowledge and experience with us! Youd da man!

You just saved me a lot of money thanks to your RU-vid knowledge my truck has reverse and 5th gear again, did exactly what you said and it works normal again🤟

Had the same exact problem on my 05 GMC 3500 with Vortec 8100. Someone had replaced the lower radiator hose, and routed the wires underneath it. That caused extra strain on the harness, and pulled out a wire that had to do with torque management for the Allison 1000 and it started throwing torque management codes. Had another problem where I received the message "Range Shift Inhibited" on the display... Common problem, mine turned out to be the ignition switch. Really easy fix, and cheap. Symptoms were sometimes no gears, other times stuck in second or third, also pcm threw many trans codes... Check for power on the large white wire connected to the ignition switch... It should have power when the key is on, if not, the switch is bad. Only tool needed to change it is a flat screwdriver, did mine in the Napa parking lot. Just make sure to line up the cogs on the new switch. Has worked great ever since.

Thanks a lot .I don’t usually comment but this video saved me a lot of time and money. This was my exact issue. I’m back on the road. Thanks again

Thank You! I replaced the fan shroud and suddenly had transmission issues. Smashed on the wiring back into the controller and boom it works. I will check the pins soon and actually fix the issue but you saved me a lot of time and money at the dealer! Thanks again!

Man this worked saved me a trouble and money. Thanks again keeping another Allison on the road.

Badass video!! Perfect fix for my truck issues today! Thank you.

Overall, this is a very helpful video. But it took me a couple of views of your video to figure out what you meant by the red connector vs the clear connector. The clear was easy to spot. It wasn't until I recalled seeing a red plastic cover laying on the TCM that I put the connector in your hand with the red cover that you had previously removed. Now that part of the video makes sense. I still didn't see where the connectors are attached to the TCM. Right now my 2004 Itasca RV is on the shoulder of a street here in Vegas stuck in Neutral. I has a red 'Range Inhibit' and a yellow 'Transmission Fail' warning lights. It's an Allison 1000(MH?) 5-speed, Workhorse W-22, 8.1L. Maybe where the connectors are plugged in will be obvious when I return to my RV and view the TCM?

I had no reverse , just unplugged and re plugged them back in . Fixed ! Thanks !

Very informative video and not staged -- like that the mud dauber nest is still on the controller.

I have a 2008 Chevrolet K2500HD with an Allison 6-speed AT (MW7). The TCM has the single, 80-pin connector. We are getting a P0717 Turbine Speed Sensor Circuit No Signal code with the engine and transmission at normal operating temperature and pulling a load. The Freeze Frame data confirm that the TSS PID is ZERO when the code is set, (All the other speed sensors are normal). A previous shop has replaced the TSS, but there was no change. I get 2629Ω between PINS 20 and 80 of the TCM connector which is what I expect. No harness damage anywhere and all the pins look good. This 80-pin connector is constructed differently than your 5-speed TCM connectors, but nevertheless I checked the pins for broken locks etc.

Thank you for this video, I'm going crazy with all the tcm codes coming and going and thinking it's my tcm, now I will check these pins, I also removed the tcm when I replaced my radiator so I'm wondering if that was enough to pull them out, very helpful video, thank you guys

Just watched this video, I’ll check the wiring when I get home this afternoon but I’m having an intermittent shuddering and not always downshifting smoothly. I was leaning towards torque converter but I’ll give this a shot

I see this alot with Allison 50/40 hybrid systems for transit Newflyer buses right at the inverter 24 pin wakeup connector and 32 pin A and B motor connectors. I change the female pins, the white pin holder and sub harness wiring due to corrosion right near the connectors. But towards the TCM its never an issue with the connectors because they are in the interior of transit buses.

Thanks for the great video and great customer service to boot!

So I've been chasing wiring issues in my 01 8.1 vortec for a couple weeks now, finally got the diagrams for modules and everything and tested A LOT of the circuits and grounds today. I was able to find a few issues that were causing problems, or would later. I thought my issues were with my TCM, allison has been going into limp mode, when this happens I'm stuck in 3rd and putting the truck into gear does not sound good at all.. but once I got to checking the PCM I found both grounds to its red connector were getting 60 ohms of resistance... I am going to double check, as I am aware this sounds outlandish especially considering some of the pins in that connector were showing over 12v... Might be a different circuit, I am not sure, but the MIL request circuit was showing around 10v. Gonna try running new grounds to PCM red connector pins 1 and 40 tomorrow, codes I've been seeing are p1781 and p1571. I'm a mechanic by trade, but vehicles have never been my forte, and electrical issues sometimes drive me crazy when I am unable to quickly solve them.

Thanks for the advise. I should have checked the connector after doing my voltage and ground checks.

Got a tcm code and shift range inhibited as well as hard shift into reverse and sometimes drive. Just swapped the tcase. Goes through the gears (1-5) good

Can a feller buy this harness brand new?

Wish I saw this before a 8K rebuild, and 2500 dollars suncoast 6 speed conversion. FACEPALM. ugh. Thanks for the video.

hello. i’m having issues with my allison 1000. truck shifts smooth through all gears. but after driving on the freeway trans is about 170 temp. if i hit a slight bump it will lock me in 4th gear and i’ll pull off and turn truck off and on. i get a shift range inhibited code. any ideas man ?????

My truck threw a p0732 code incorrect gear ratio along with a p0700 5 speed Allison what’s your thoughts

Thanks for the video. I have an 03 gmc with the 5 speed allison. I have codes p0846 and p0700. It seems to start in third and stay in third. Reverse is fine. Up to this point I haven't had any problems with the transmission.

You're awesome!! Thank you!! Mike Fitzgerald Calgary Canada 🇨🇦

I hit a rough spot in the road and the 1000 allison kicks out of any gear . And i put it into neutral and back in drive and go down the road to the next big bump. Once i didn't shift out and got two codes. P0735 and p0700. Both fifth gear not in cync.

I have 2001 Allison 5 speed Checked plugin. It looks great. How do I test if the TCM. Is bad or not. If bad what will one cost me, programmed and ready to go?

I have an 03 Duramax lb7 with an Allison Transmission the transmission was gone through before I bought it that's all I know was pulling a camper last week this week it has started hanging at the 3,000 RPM mark if I'm giving it fuel hard if I stay in it light it'll change just fine I watched your video and it sort of sounds like I could have that problem I've got two codes they come up first code is p 1621 and the second code is p1781 both of those are communication codes just thought I would ask for your opinion thanks in advance one of the thing I've checked my batteries and both batteries are fine my fluid level is fine in the transmission as well guess that's two things thanks again

Hi, my 2002 chevy 2500 8.1l automatic w Allison will run in reverse but gets the blinking D in drive and won't move. Do you think it could be the same issue?

Checking my pins today. As when cold shifts hard from 1st to 2nd once warmed up truck shifts perfect. Ideas?

All of a sudden I'm getting a hard shift into what seems like 2nd gear and I only have that gear in forward . Reverse fine . Allison 5 so 2002. Replaced NSBU ,same .

I have a 5 speed Allison. I'm getting a couple code's P0700 (TCM) & a P0748 (pressure control solenoid valve control circuit). The thing is the codes are not always there I can drive around for a while come back fire the truck up and I have the codes, then shut it down come back no codes. Do you think these pins could be causing my issue?

Changed the water pump and the pin back off!

Eric, Did you notice the connector in your hand has a loose or bent pin!?! It's the second one from the top left. I tried to read if anyone else has brought it to your attention already, but didn't see anyone mention it.

Me pad you know to go forward and neutral and reverse went dead wend i was driving and the speed omerer went dead too and i cant find the problem and don’t start

Thanks for the video. I'm hoping you still look at the comments on this video after 5 years and might be able to give some help. I have an 01 3500 8.1 with the Allison 1000 that is giving me a P0732 code. The local shop says I'm looking at $4800. The symptoms are that it intermittently will start shifting hard (specifically going into 2nd gear from first and third), then after that happens for a few minutes it won't shift out of 1st gear. If I shut the vehicle off for about 10-15 minutes and restart it, it will work fine for a bit. The time that it starts to work normally after a restart seems to be getting shorter each time, not sure if it is related to temperature. Thanks ahead of time if you or anybody else can help give me a direction to start looking.

hi, I write from switzerland, my Silverado 2500 hd has a problem when it change to 4th and 5th gear, when I change I feel a big blow in the transmission, I have the error codes p0700 and p1720, also I get stuck in the 4 gear, it no longer changes in the fifth thanks a lot for the answer

Great video! I just subscribed to the channel. Do you have any recommendations for a 2018 GMC Sierra 2500 L5P that when put into reverse the "R" on the display starts blinking and the truck won't go into reverse? I just changed the TCM fuse. We are scheduled to leave town today for an event 3 hrs. away for our small business and we are stuck at the house. Trying not to panic. Any ideas to try first? EDIT- Codes being shown are P249D, P0701, P0731, P0751, P0756, P06C6

I have a 2001 Chevrolet Silverado, 3500 with an 8.1 Allison transmission. The TCM is not communicating with the scanner

I have no down shifting and no power going uphill and high rom shifting took ti sllison techs they said no tcm signal unable comunicate to TCM they recomend TO BUY NEW TCM. to reorograned then chk if it fix problem or they go from thete once tcm comunicatiin is available. What di you think????🤔🤔

Truck runs fine, but decided to now get out of 1st and than not go into reverse when hauling. Tcm connection fail, section 2 communication problem and tcs falt, more of a wiring or tcm issue ? If wiring can I just buy that section or must the whole

so i have an o1 gmc sierra 2500 hd w 8.1L gas and allison 1000, also have an 02 Silverado 3500 dually w LB7 and allison 1000. the Silverado has be wrecked and is a parts truck, my 2500 is my daily, yes fuel cost is horrible looking to change soon as weather permits enough work to do so. 3 days ago and 3 other times while slowing down to make a turn i get the grinding sound as if shifting a manual with out a clutch just not as loud, its a steady grind while slowing for turn my light is green but at about 20mph grinding stops much the way it did other times intermittently, i know nownits not abs pump as i never pressed it. also this time service light, im accelerating slightly out of turn, its in way too high a gear but holds it, luckily my destination part store is next turn and around to park. whole time stayed in same high gear. dignostic tool says tcm failure, short to ground, 4th gear ratio too high, and something about a solenoid, also relists some of same codes twice or more, for a total of about 10 codes. used 4 low to load onto my trailr to pull home, offloaded same and parked. will check connections soon. whats chances tcm from 02 diesel 3500 will work on 01 2500 8.1 gas. sure sbift points will be different rmps and torque converter and pressures may be different. can it be flashed to work, how much $ if i pay shipping both ways. i dont trust the local dealerships, from exp they are parts changers only.

Could this cause my truck not to start? And also the gear indicator won’t show and trans temp won’t show and when I start it with a screwdriver to the starter it like stays in 3rd gear and won’t go out of that gear. It sometimes fixes itself and drives normal but then sometimes it will mess up and also will say service 4wd

I have no com with t cm wont crank and I was checking the ground pin1 and 5 the continuity is not stable and the ohms are 50 to 300 engine ground to pin. But my power probe shows fround signal np.and my etm shows a pink wire on pin 2 that is not there?

I am having a check trans and range inhibited lights on an 03 international 4300 truck and it's stuck in low gear and won't shift into overdrive..notice the speedometer gauge isn't moving up.

My truck has been running great. I cut it off night before then next morning its just turning over. 2003 2500HD 8.1 with Allison transmission. Ive checked all wires. It is showing 40 codes. Saying heated trans pluse high voltage and low voltage. Also showing all gear codes. I cant .ake sense of it. I need my truck for work. Caan anyone please help with any advice 🙏

@Spartan Autoworx Thank you for the video. 2002 8.1 Allison 1000 harsh downshift from 3-2 and 2-1 almost like rpm increases to the point of being harsh. no codes. Seems ok in tow-haul Can you help with some advise? Thank you!

Hi I have an 04 duramax with an Allison it’s saying shift inhibited and it has all the forward gears but not reverse I am getting a scanner to look at the codes but wondering if this is the trouble or those a b solenoids

So I have a question I was running 95 and then looked down my transmission was running hot so I got it rebuilt but it is not shifting and when it does it goes in for one second then it kicks out of gear what is going on help and I checked the pins on the tcm they are all good

So, my truck is throw both u0073 and u0101 do those both usually co-exist?

I have a 2000 frieghtliner fl60 ambulance with a 6 speed automatic with a push control box, it has been sitting for 3 years and now when I try to drive the truck it starts out showing 6 on the control box and doesn't shift it will display a 1 on the control box and will not go back to any other gear reverse or even back to neutral I will have to turn the truck off let it sit for a little bit started back up and then I'm able to put it back in neutral or reverse I'm hoping it's something simple, before the truck was parked the transmission did not have any issues at all

Have a 01 8.1 with the Allison, wont come out of park u can move the shifter but transmission doesnt respond and the letters flash and if u unplug the bottom plug on the nuteral saftey switch itll go into reverse and forward but acts like its second gear were do i start looking ?

My 2003, LB seven has 200 K miles, I just had all kinds of work done to it a shift kit even and everything seems sound for the most part except for when I go over speed bumps. It does not matter 5 mph to 15 it always jumps out of gear. Any ideas on the cause

I have a 2008 GMC Sierra 1500 4x4 went to pass a vehicle on day down shifted to third and wouldn’t shift to 4th till about 5k rpms then was stopped idling in drive went to take off an it was like it was in neutral had to turn truck off an start again to be able to move maybe 200 yards an it’s like it went into neutral again . Have to keep turning off an on to be able to move short distance.. Any help or ideas on what’s wrong only owned the truck for 2 weeks !

I have a 2005 Chevy 2500 lly 5 spied & im getting P0700 & P0735. Drives and shift fine till I get on it and switch’s to 5Th gear and goes into limp mode and stays in high RPMs

What would cause my TCM not wanting to connect to the scanner?

I have an 05 lly and I am getting the range shift inhibited warning when it is cold and it wanders between in gear and not but once it warms up it is good to go.

2005 4x4 6.6 five speed had speed sensor codes and shifting issues replaced all speed sensors and scanner shows good operation. still coding speed sensor p700. Sometimes it starts out in fourth gear, sometimes stuck in 1st. also abs brake actuation. Checked both TCM connectors and found no pulled out terminals. put it back together and have a no crank. batteries are good shift indicator shows no position (not in park?).what could have happened ? now I cant even test drive to see if connections just needed cleaned ! any help out there would be awesome

I have a 2002 6.6 turbo diesel and every time you try to get on it she will not pass 2,500 rpm and won’t shift and hold the gear and turbo unless you take your foot off the gas and give it gas again I don’t know if the issue is the passing gear or just something wrong with the transmission in general please help!

2001 Chevy 3500, 8.1L gasser with the Allison 1000 5 speed. I'm getting an erratic trans temp reading on my gauge cluster. Sometimes its pegged at cold startup, sometimes it shoots from zero to 200, then creeps up and stays. Then it might drop to zero or regular operating temp, all over the place but not a twitchy gauge like these clusters sometimes exhibit. When it pegs hot, I get a "trans hot, idle engine" message and trans shifts hard, but only shifts this way while gauge is reading incorrectly. I've checked these pins you talk about and seated them all. I can't see any issues with them, no retention tabs are broke. I was able to unseat and re-seat every pin on both connectors even though none appeared loose to begin with. I checked trans harness for fluid in plug at trans, there was none. Ive checked resistance on on the pins for the temp sensor in trans and according to the specs for temperature/resistance nothing seems out of spec. Ive checked all grounds I could find, and I looked them up to make sure I didn't miss any. Including the ones on the interior near the gauge cluster under the a pillar At this point the only things I think it could be is TCM. Only caveat is it appears the previous owner/owners spliced in a shitty old security system but it did not appear to be hooked up anymore as most of the wires where just cut and Ive had no typical failing aftermarket security system issues like no starts or sudden dying etc. so Im not sure if thats contributing to the issue or if its just a distraction that needs attention later. Do you think it sounds like my TCM has failed or do you think I should keep digging at the botched wiring job under the dash for maybe a bad splice or tie in? Thanks for any help. I tried to exhaust all options I could before I asked you.

What is the part number for those connector pigtails

Hey man I have a 2001 2500hd with the 8.1l v8 and it keeps on shutting off on me out of nowhere and I’ve replaced a lot on it and it still shuts off what do you think it could be

I have a 2003 Fleetwood motorhome with a 8.1 engine and a 5 speed transmission Allison having problems with my downshift button the transmission works fine except the button stopped working doesn't downshift to 4th what could be the problem thank you

Hi I'm new at this. I have an 01 2500 HD 8100 engine with the Allison 5 speed. I get an intermittent overheat on my dash info monitor. Along with the gauge going up to 300 degrees. Checked the temp of the fluid. Also checked the cooler lines. Appx temp was 140 to 160 F degrees. Changed both filters, oil etc. Checked oil lines had no blockage. Still reads high temp. But does also drop down to normal in a second. Please help. Jim

Watched the video. Yes I have the same issue. Spend 2 hours getting 2 pins back up. Plastic holder was broke and I kinda fixed one pin. Is there a after market fix for this issue?

When it has a bad pen like that will it throw a code?

Trying to troubleshoot a 2005 school bus w/Allison 2000. It seems to be stuck in 3rd gear and the check trans light is on. Initially, we turned it off, turned key to on position and cycled through d-n-d-n-r-n and it came out of limp mode for a while, then went back into limp. Upon inspection, the transmission was very hot to touch (no gauge). Had a local shop try to pull codes and nothing showed up. Any help appreciated.

I've got an 03 gmc with an 8.1 and allison 5 speed, I've been having an issue with starting, check engine light threw a bunch of trans codes, hard shifting, gear indicator has been working off and on, the main thing is the starting issue. Sometimes it's no crank or clicking of the relay at all, sometimes it clicks or starts to crank and then cuts out before the truck fires, I don't remember what trans codes it has threw me, but I've replaced the starter, connectors on the wiring at the starter, ignition switch all with no success. I'm going to try checking the tcm harness but is there anything else you guys would recommend?

2007 Chevy 2500hd 6.0 Allison trans drives almost perfect in"D" , but when I select tow/haul mode rpms jump WAY high like over 4000rpm when I'm trying to slow down, could these connectors be the problem as well?

I have a 06 Chevy 2500 with the 6 speed Alison replaced the tcm do to really hard shifting didn’t fix it it’s a new tranny as well could this be the issue on a 6 speed as well?

I have a p0778 please help check everything can’t figure out 😢

I have a 2001 Silverado 2500HD 8.1L with Allison 5 speed tranny. If I purchased a used TCM from another 2001 Chevy Silverado exactly the same as my truck, do I have to reprogram the new TCM before installing it? Do they sell the wiring harness that goes into the TCM? The clear control module was loose and the plastic piece that sits on top locking the pins in place was also loose. I did my best securing it and prevent the connecting harness from rattling. But I will see what happens and any information from you would be appreciated.'Thanks

I'm having an issue where my truck losses reverse and when I shift into drive it slams into gear and acts like it's in 2nd or 3rd gear..service light flashing..shut it off for a bit..then it stops and I have reverse and shifts normal into drive..truck isn't drivable like this but when the service light isn't on the trans shifts great zero slip..I'm going to do what you shown hopefully it helps..was a plow truck

Hey brotha, my transmission has 42 different codes, and it did the same with 2 different transmission swaps of good transmissions. im gonna replace the internal wiring harness. Would you do this next, or what is your advice? i was thinking bad TCM, though, with the random DTCs.

I have an 09 3500 with tha allison 1000 .it developed a shudder in low take off gears. Especially pulling a traylor. Only code it is throwing is glow plugs. Any idea if it is tyranny or not?

Can you program one before you send it so I can just put it on

What is the part number for this? I'm having a very hard time finding this harness. 04 duramax LLY reading code p0872, new valve body, nsbu, throttle cable. Really interested to find this harness

Awesome video thanks so much

Got an 01 that's throwing a p1760 and it will not go into gear. Put it in drive move a couple feet dash goes haywire code pops up and won't go forward. Think this is the problem?

David Victurine I have an 02 2500 Hd 6.6 When the vehicle is started the square gear indicator light does not always light up. any suggestions

got offered a lly with a new trans with the 6speed i guess kit in it because it’s still the 1000 trans but it has the code p0872 and he says it’s a dirty valve body but it’s stuck i. 3rd gear and scares me lol. what do you think trans has 42k

Do i have to disconnect battery before unplugging the tcm on my 03-lb7.

I have a 05 GMC Duramax that is showing shift inhibited and will not going reverse could this be the problem

Would this cause my trans temp gauge and gear select not to work also?

I got a question if you have the time. I push my tow button and no lights come on. I do have a edge evolution tunes on my truck. Do you think that's a button issue or a wire issue?

We have a Allison 5 speed that will shift through the gears cold but when it warms up it will shift 1-4 perfectly and then it won’t hit 5th any help?

Mines missing a bunch of those metal pins. Do I have to order a whole new set of connectors ?

Hey I have a 2002 model international and i have every gear but reverse and I replace valve body speed sensor shift sensor on side ot transmission. Could this be the tcm I replaced the valve because had a stuck valve in solenoid a. Any information would be helpful thank you. Levi

Are you still able to get tcm. I have a 04 lb7. That gives me a p0700 code

have you done a vid on the repair of the pins?.. especially the brittle plastic ones.. Do you just use pliers to pull the pin back into place?

Hi, my Duramax works fine when it is cold, however after driving for 1 hour or so, then stopping, parking, then starting up and driving again, the shift indicator does not show up under the PRND3.., but will jump to the 3 when shifted to drive and it will not drive, if you let it cool for about 20-30 minutes you can get it to go into drive and go, however after driving another 45 minutes to and hour it goes into a limp mode, shifts down, over-revving the motor and then has to be cooled down before being able to drive. Is this the TCM? I took the TCM off, removed the plugs, looked for corroded plugs etc then put some dielectric grease back on and reassembled, hoever it did not fix it. What do you recommend?

The truck does fine 1st 2ed and 3ed gear but want go into 4th or 5th and when it gets up to temp it try’s to slip out of gear. But it does fine for in them gears until it gets warm. What do you think could be wrong?

My 03 f650 did a unusual hard shift and check trans light came on. Truck went into a limp mode and stayed in one gear. Parked the truck for an hour or so started it up check trans light was off and shifts were normal. After about 30 minutes light came back on and went back to limp mode, could this maybe be my issue?

So my trucks been shifting harder lately especially in 2 and 3 so people are saying it’s the fuel filter but I’m not sure. But could this also be the cause of it?

Well I took ur advice and now my truck wont start. Was supposed 2 disconnect my battery first ?