I have a fleet of DD13 engines paired with Allison automatic, only one paired with DT12 and it has the same problem for the past two years. The problem started when the truck had around 500k miles. Basically, when the truck hit any bump or pothole, it would be out of any gear, and into Neutral. Right before it did that, the Hill Descent, both Re-gen, Start Blocked, and ABS lights would come on. I took it to local Freightliner dealer at least five times for the problem, they eventually lowered the trans and replaced PT Can, split-pin bushing, clutch, wiring harness, new filters, trans fluid, and other things. Now, the problem is that with a load and incline, all the dash lights that I mentioned before would came on, the truck would go into Neutral no matter what gear it was in, but if you let go with the accelerator pedal, the truck would go back into gear, but the cycle never stop, until the truck lost enough speed, and had to pull to roadside to re-start.
How about the counter shaft brake? My DT12 revs up when shifting from even to odd gears. When I take off my feet from the accelerator pedal when it is about to shift, it will shift without a problem.
I’ve got a DT12 that will not shift at all, I’ve done a clutch leak test, it’s passed I’ve relearned clutch Transmission will not re learn tho, I have a procedure fault stating the countershaft speed is too high
I have a DT12 in a 2016 and it will not pass transmission relearn but will pass clutch learn. It gives me the fault “minimum distance selector”. I just replaced the shift actuator and the split pin and the transmission wont go in neutral. The dash shows two dashes and the truck will start but wont move. Before this happened we had an issue where the transmission would get stuck in gear and keeps trying to pull forward even when you come to a complete stop. You would have to turn off the truck to stop it from moving. I was told it was the actuator or the split pin so I replaced both and reinstalled the software for the TCM. I dont know a whole lot about these transmissions so any help would be appreciated.
I have a 2017 DT12... When I'm loaded, if I have my foot to the floor, there will be slipping in 10th 11th and 12th.... Usually at the lower RPM range of those gears, it'll slip for a second and then come back and grab and maybe slip some more, maybe not. But if I'm easy on it, it may not slip as much. It's hard to get it to do it bobtail. But it does still do it, if my foot's to the floor in 12th gear...... If I shift manually, and run the gears a little bit tighter, higher RPM, without my foot to the floor, and I shift into the next gear, the RPMs don't drop as low into the next gear, and I can avoid the slippage. Any thoughts?
Had the same problem. 2020 Cascadia with 525k miles. Spent 3 month in/out of the shop. Did every testknown, sent the data to Daimler , no luck. Finally changed the clutch and solved the problem.
DT12 when pulling a loaded trailor 44k. I slow down to a stop light or brief stop (down shift). The truck accelerates from a brief stop. Truck jerks dives, stutters or sometimes stops especially up hill. The code "wont shift into gear" and " shift to neutral starter block", the codes rhen clear. Come to full stop shift into gear and drives fine. Only seems to happen when coming to a stop from a higher speed then accelerating like at a stop sign. The truck shifts fine when not loaded. Seems to happen with a heavy load so far.
I know this is probably a stupid question but there's no question stupid not the one that's not asked does the transmission do I have to do any programming to the transmission before I install it
F$&K Speedco - They wanted $150.00 shop labor and several hours of wait time with only 1 guy working the lube side for changing out the fluid - I skipped it and got it done in about an hour $50.00 shop labor in Wilmington CA - And FYI DD12 fuid ain't cheap ! Paid $93.00 a gallon from Freightliner for 4 gallons
My dt 12 hesitate to shift to neutral after stop. What should I look for? Oh , secondary air tank drop fast , its randomly drop 10 psi within 5 seconds. Thank you
Hi steve. Hope help me find problem whit my transmission when driving show red scring transmission fault need repair service show F snd the gear but chang gear ok i stop truck turn off 5 seconds and turn on back snd the transmission Fault go off normaly do it when use engine break to often. Thanks
No throttle,truck shift to drive and neutral however will act as if it wants to move but will not move either direction drive nor reverse. i really don’t know what’s holding the truck to move. No codes only check engine light. Freight liner cascadia DD15 with DT 12 engine. Will appreciate your input. Thanks.
My truck has 650,000 miles. I recently replaced that stupid split-pin and had the mechanic inspect the clutch, he tells me clutch is fine. This is the original clutch (I bought it new) what's up with that? Do they last that long?
I haul chemicals with tank surge. Do you recommend getting a manual over the DT12 Automatics? It's hard finding a 3-4 year old truck that has a manual transmission.
Hey Steve, my ABS light is coming on whenever I push the brake paddle It will be quick for a few seconds and then goes back off. It just happens when I have a trailer any recommendation thank you
Hi,mine shift to 7 gear ,then when I accelerate it shows me 7 gear but truck not going,just down shift to 6 and it’s all good ,it happened few times what it can be? I got this truck 2 years ago,I have no chance to change fluid maybe I it’s fluid ?thank you
Hey Steve, I have a DT12 on a 2017 cascadia evo I have started having a issue similar to what you are explaining on the video my dt12 recently started going into neutral while up shifting from 11-12 and more often while down shifting on low gears. When I arrive to a stop or red light it tends won’t go into gear just stay on neutral and I’ll have to switch to drive or reverse and neutral on the handle while it’s on neutral and trying to go into gear it’s making shifting hissing noise like it’s trying to enter but won’t enter gear at some point it’ll go into gear and on handle I’ll switch to drive or reverse depending what I’m trying to do at the moment , can that be related to the relearn ? I’ve added over 100k miles and haven’t done a relearn while doing pm service.. any thoughts on what it might be ?
