Why you SHOULD rebuild your own manual transmission in your project car! 

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Exact words my brother said to me

Same here, engines no problem but gear boxes have always been this mysterious tabu, haha... I am going to do it this week.

Good luck!!

I bought a manual car recently, it had been 30 years since I’ve owned a manual car. When I learnt to drive I was never really taught all that well. Every drive I’m learning something new, The thing with manuals is feel and timing and finesse and sympathy, manual transmissions change as you drive them and they are very alive.

And so does finishing a video from time to time! Just put one up finishing that transmission build.

My Camry with 450k miles started popping out of 5th. What I noticed but never gave much thought to was how the shift lever in some gears would move alot when I would put power or back off the gas. I thought I had bad motor mounts. I swapped the trans when it finally wouldn't stay in 5th. I drove it in 4th for about 6 months before I found a good used replacement. What I found on my old one was that the bearings and spacers were worn. Under torque, the entire gear train moves in relation to the parallel clusters it meshes with. It moves so far that it jumps out of the little tabs that clicks the gear in place after you complete a shift, hence it pops out of gear. Changing the bearings and spacers would have fixed the problem, plus the 5th gear teeth were worn from jumping out of gear so much..expensive parts. So it was better for me to get a used one. Once it was installed, I noticed that the shift lever didn't bob back and forth any more.

You'd be surprised how little experience is really needed. Anyone that can drive a manual and shift through the gears would he able to figure out which gear is acting up. If the transmission keeps popping out of a specific gear you've already done 90% of the work. You'll know what synchro, shift collar, and fork to look at. And if all the other gears are shifting correctly you'll have something to compare it too. Broken teeth are super easy to spot (cause they are gone) if a synchro is burnt up you'll be able to see a difference in color compared to the others. The shift forks are only machined in a couple places. So it that cast surface is shiny, chances are it's hitting something it isn't supposed to. The amazing think is a guy on youtube with no experience at all messaged me on youtube and figured out 95% of his issues just by digging into it. Most of our conversations were validating what he found and double checking a couple things that looked backwards compared to mine. He bought a synchro rebuild kit. Spent a couple weekends working on it and got it all back together. I haven't heard from him in like 2 months now. I'm assuming its still working or I would have heard about it.

You might need a press to remove gears or bearings off of the shafts to get to the synchro if the puller isn’t strong enough. A pair of snap ring pliers is a must. Other than that a set of sockets, some screw drivers and some good music is all you’ll need.

The only "special tool" I've used is the press. A set of sockets a flat head screwdriver and some snap ring pliers is all you'd need to get started on the transmission. There is probably a Corvette rebuild facebook group. If you need the press you could probably reach out to someone in a group with the same passion and they might let you swing by and use their press. I highly recommend taking lots of pictures too.

What transmission are you thinking about rebuilding?

@@Obscuremotorsports I’m thinking about rebuilding my 240z gearbox. FS5C71B or FS5W71B, not sure which it is yet, have to pull it apart to find out...

@@Ryan-wf7sh Yes! Do it. That would be an awesome transmission to dig into. If you don't want to disable your car, could you buy one for cheap and rebuild it and then swap it? That could give you a longer timeline so you could take your time and be patient with the rebuild.

@@Obscuremotorsports it’s project car so I have all the time in the world... I will do more research and learn more about my gearbox. Knowledge is power so I think if I learn enough I might be more comfortable. Thanks for the encouragement!

@@Ryan-wf7sh Don't forget about the importance of learn by doing. Reading 100 books about the transmission is good to get the theory. Cracking those case bolts open is when all that theory goes out the window and it become practical. Have fun!

You almost got the point of the video. The reason I shared the broken bit is because even though i didn't do it perfect, I'm still happy I did it. And the extra $100 on top of the seals/ synchros I replaced is still 1/4 of what I'd pay to have it done by a shop. So even if you make a mistake and break something you'll still save money, and you'll have valuable knowledge for the next thing you disassemble. The lesson I learned in breaking this gear I've already used 2 other times taking other gearboxes apart. If I took 30 more seconds to understand what I was doing I wouldn't have broken that gear. But it's already paid for itself when dealing with gearboxes that have much harder parts to find. I hope you reconsider again and dive into that MTX.

Hey Terence! Glad your thinking about diving into your transmission yourself! Since it sounds like it's only one gear a worn out synchro is a strong candidate. Especially if it's secon, who knows how many times it's been started in 2nd and accidentally shifted into 2nd instead of 4th. I'd start by changing the oil in the transmission. Catch it in an open container so you can inspect it. If there are chunks of metal, you're in for a good time. If the oil looks like it has tiny silver sparkles in it you might have some premature wear on the gears or shift collar. If the oil looks like it has tiny brass sparkles mixed in it, that's a sure sign the synchro is damaged. If it looks like used oil you'll have to dig deeper and start the fun. When you do take TONS of pictures. From multiple angles and of features that tell the orientation. The Toyota has big corner breaks and grooves on the shift collars and spacers that tell you how they are installed. Look for features like that before you remove the part of the gear stack. I'm not familiar with the transit driveline. If you're lucky you'll be able to disconnect the front and rear prop shafts and it will drop out. If you're unlucky you'll have to from the front differential before you do that. Only way to find out is to crawl under it and look! No special tools should be required.

@@Obscuremotorsports Great advice and tips

I'm not familiar with the 250s transmission codes, but there are probably a few online shops that have what you need. I'd suggest looking for an IS 250 forum and read some threads in part stores. You probably don't have to ask a question, just do some searching for part stores. I've bought stuff off eBay, lowrangeoffroad, LC engineering and a few other Toyota truck based sites. Which ever is the less expensive is the place I'll go. Good luck!

I suggest before getting the new transmission go ahead and rip open the current one. And figure out if you can repair it. You won't have tow worry about the logistics of transporting the new one and then get rid of the old one. If you have any questions you can find me on Instagram and I'll do my best to help troubleshoot the transmission once you have it open.

That's a hard one to pin point off the cuff. The first thing I'd do is check the fluid level the fluid color and the drain plug magnet if you have one. It's always good to make sure the level is right. When looking at the old oil you're looking for what looks like really fine gold colored glitter or silver looking glitter. If it's gold chances are you have a worn or broken synchro (made of brass) and if it looks silver you have a worn or broken gear, or bearing or something else. If there are chunks of metal on the magnet something is broken. You'll have to start taking it apart to find out what's broken. Be aware that it could be something from a different gear. When in first the shafts are linked to the first gear, which means all the other gears bearings are spinning freely so it could be something on a different gear that gets excited when only in first. I'd also check the shift travels. The fork could be traveling too far and something is rubbing. You could try lightly pulling and lightly pushing on the shifter while driving in first to see if the whine changes. Check bushings in the linkages aswell to make sure things are moving correct. Hope that helps some.

@@Obscuremotorsports yea cheers for the advice buddy👌...I mean I'd throw a replacement at it but at this stage those gearbox are lik hens teeth being the quattro...and first is a different ratio than a fwd b5 of the same year...which I have two fwd drive gearbox...I mean I could probably split them and fit the torsen differential ...I'm thinkin it may have had a hard life as it is a quite lively car compared to other diesel b5 Audi I have...thank you Nabil👍

I mean, someone does work on those, why not be whoever owns the vehicle? If your business or or livelyhood depends on it I wouldn't recommend it, but if it's your project vehicle and you want to learn how it works, I still say dig in!

@@Obscuremotorsports I completely agree with you truthfully! I just wish it didn't need a $200 tool to take it apart. If I had my own shop it would make more sense to have though.

No trouble putting it together. Just trouble taking it apart. That's the only way you learn. And because I learned, now you don't have to! You should definitely attempt this.

I’ve seen all sorts of gearboxes with different parts being damaged before others. If a bearing gets too hot and seizes it can spin inside the housing bore. Usually the external rings on bearings are a loose fit than the inner ring on a shaft, so they have a tendency to slip easier.

There won’t be any marking on the internal parts. You’ll have to order them based on the transmission code. This is usually stamped on the case somewhere. I’d be surprised if you had to replace the forks. They typically don’t wear, unless something is really wrong. All the bearings will have the bearing number printed on the edge of the bearing races. This is helpful to verify you’re getting the right rebuild kit. Then you can use that information to trust the synchros in the kit etc. if you can take apart the transmission before rebuilding it, you cab compare pictures to what your holding. The last bit is to know that not all manufactures made there own parts. They will work with synchro manufactures and gear manufactures. Which means lexus, toyota, vw, and others will share common parts. So don’t be too concern if you see a part that says it will work with multiple makes and models. It’s true and will be okay.

Thanks very much. I wish I had your knowledge on transmissions.

All the bearings have external races that slip into the housings. Some of the bearings roll directly in the shaft. Some have internal races that need to be pressed. But all have external races. Hope that helps!

It's the synchros that wear. The gears are made of much harder material and the gear pairs are always meshed in modern gear boxes. So the only think that will wear out the gears are more power than they are designed for, or really really contaminated oil. Synchros on the other hand are the parts that get pinched, and mushed and mashed. When you grind gears (in a modern manual) you're actually grinding the synchros, not the gears. So it's most likely the case you only need to replace the synchros.

@@Obscuremotorsports ah nice thanks for the advice and the video!!

Designing a geartrain and working on one are completely different challenges. The work done to develop a gear system to meet requirements for a client is challenging. Lots of understanding tooth stress and misalignment from shaft deflection and housing twist under load and temperature changes. Then there is bearing life you have to estimate. It takes a while for people to learn that. Taking apart a gearbox and putting it back together on the other hand is something anyone can do over a couple weeks. I took transmissions apart for fun many years before I designed them. The point of the video is get people familiar with the only "complex mechanisms" in a transmission, the synchro, which really isn't complex if you just need to know how the pieces fit together. It's like a 1000 pieces puzzle, all I need to figure out is how the pieces go back together, not how the pieces where designed and cut, and made.

It really isn't scary. With a small amount of patience and a willingness to pay attention to the details anyone can work on their own transmission. Nothing in your list of components is magical or special. It all pieces of metal sliding or rubbing together to make something move as long as you pay attention to how they came apart, you can get them back together. I'm not trying to deter people from taking the path you took. Some people want it done fast, and have the money to make it happen. And as long as you and them are happy, that is all that matters. I'm reaching out to the people that have the smallest bit of curiosity and have the interest to tinker and make mistakes and learn. The people that want to drive up to their friends house and say "I rebuilt my transmission and its still working!". There was a gentleman (We will call him JB) that messages me on IG asking about the same transmission I had. He had no prior experience with doing transmission work, and got his truck for $500ish and it would slip out of 2nd and 4th. when JB had messaged me he had completely taken the transmission apart and needed helping getting the shift forks back together (cause I haven't put that video up yet). We went through his entire transmission and found the syncro of number 2 was cracked, the shift collar for 4 was put on backwards (which wore into the fork) the washer behind 5th gear had a cut off bolt instead of the alignment pin. The previous owner DIYed it the incorrect way. No patience, no attention to detail. JB took the time, found all the issues, bought the correct parts and waited for them to arrive. I think he ended up taking apart the transmission 4 times before he found all the issues. It's been a month since he got it back in the truck and he has been daily driving it with out any issues. in total he spent around $300 in parts and you can tell from his messages he is proud of the work he did. Those are the people I'm telling they should rebuild their own transmissions.

@@Obscuremotorsports 90 k1500 full size. Manual 5spd. No sticker. Gm put 5 different trans in it. How do I find the proper kit before tearing it a part

@@williamgoodwin3245 to be honest I'm not at all familiar with GMC trucks. Even though they might have had 5 different transmissions there are probably trim level details that will narrow it down. You know which engine you have, I'd start with some research to see what combinations of engines and transmissions there were. Depending on the driveline setup there could be different transmissions for 2 wheel and 4 wheel drive. If your rear diff is original you can find out the gear ratio and see what transmission were matched with that. I'd also climb under it and take as many pictures as you can. If you can pull off the boot in the cab, take a picture of the shape around shift linkages and the shape of how they enter the housing. Look at sensor locations or any unique features. Find reliable pictures of each of the 5 choices and after a little work I bet you'll figure it out. Good luck!

1638jaw every bit of info helps to unravel the mystery ,i've bought a 2nd hand 5 speed, theres noticible backlash between input and output shafts but turning by hand no audible noise, no movement in either shaft, i plan to do two tests ,oil analysis plus i will make up an adapter and spin gear box using my drill if OK in she goes thoughts