I've spent a lot of time trying to find what's wrong and can't find anything that fits my problem. I bought a 2001 2500HD duramax with 5 speed allison. It had a leak at the bellhousing and also came with a full transgo kit. So I took it out and decided to take the transmission apart and install the kit. After reinstalling the transmission, it slips really bad and wont move sometimes. When it does get moving, it wont shift out of 1st. I thought it might be the nsbu so I replaced it and it didn't work. I have my own shop and have built several motors before but this was my first transmission. I made sure everything was put back right. I only replaced 1 C1 clutch due to some chipping. The rest of them were in perfect shape and checked with a micrometer. I figured I would see if anyone knew anything. I was hoping for some advice from Mike L. as I understand he is the expert in these trannys. Thank you for any help
Allison 5sp: Issues after rebuild
- Thread starter Weisguy
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Ok. After hooking up an edge cts2 to the truck I found out the torque converter lock is not reading D but it does read PRN. It's showing the transmission is in neutral and don't allow movement. Any ideas?
Oil level good when Idling? Codes? sump filter didn't fall out when you put the pan back up did it?
The fluid is at the right level. No codes are present except when I'm messing with it and making them appear. I made sure the filter was in all the way and it wouldn't come out. I'm working on a theory about it being the wiring between nsbu and tcm.
unplug the case connector at the back of the trans, if you have 3rd & reverse it's electrical if not it's internal.
Ok. I unplugged it and it didnt change anything other than it made it start grinding when I put it in park. The truck has gotten worse and will only move forward at 1600 rpm and it'll only move a few feet before it stops. I really need to figure out what's going on. It's confusing me so much. I have the atsg guide for the allison and have read every page trying to figure out what could cause this. I'm going to try to include a picture of the monitor that shows its displaying N when I'm all the way in 1 on the shifter.
Yes. It had a leak so I didn't want to drive far but I did make sure it went through all the gears before buying it. It won't let me upload pictures but my cts2 has a pid for torque converter lock and gear display and it stays in N for all forward gears.
Ok. I figured out how to force the display to be in a gear I choose. But it still won't go to drive instead of neutral. Could it be the tcm itself? It always thinks it's in neutral so it doesn't apply pressure the the cluthes?
Well if you don't have a solid 3rd or reverse with the case connector unplugged it's internal and the trans needs to come out.
No one is there to see what you screwed up nor can we tell through the internet. At this point, it's best you take it to a shop before you really cost yourself some money.
I touched everything for the c1 c2 and c3 clutches. The torque converter, the input shaft, front pump, valve body, solenoids, and a lot of clips. So I need to know which of all those pieces would cause this problem.
The shops is what will cost me a lot of money. I'm not looking for anything like all you guys have. I'm not sled pulling or drag racing. I just want this truck to pull my jeep anywhere without any issues while getting good mpg. I don't want to spend a bunch of money so I'm trying to do it all myself. A shop would charge me 2000 dollars to replace a 2 dollar part.
But the shop will know what you screwed faster and cheaper than you are going to find it. You have no diag skills or even a general idea where to start. You went into the trans blindly, slapped some clutches in without verifying anything once installed and now the truck doesn't move. We get guys like you all the time who attempted something on the trans and screwed up something internally, then want us to magically fix it because somehow we will know what you did. As you said, there are 100 parts in there and we don't know what you did or didn't do. How your trans is acting now is not a simple fix, it's pretty f**ked.
This is the harsh truth. It ain't sugar coated.
Also, a CTS will not tell you every code that the trans is throwing....
You really screwed up trying to save a buck. Now's time to pay the piper.
You really screwed up trying to save a buck. Now's time to pay the piper.
Well I figured I would ask the "experts" for some help. But obviously Noone knows anything about these transmissions. You should all know exactly what I did because all I did was install the transgo exactly to the intructions. I didn't go messing with anything else. It's the same as a lot of you say you have installed on your own trucks. I do have diagnosis experience, just not on a transmission. I do have extensive electrical experience (thats what I do) and I think it might be an electrical issue but I don't know anything about the allison tcm. If I pull this Trans out and take it to a shop and the problem is in the truck, then I did all that for nothing. I want to find the problem before I go fixing things that don't need fixed. That's where you waste time and money. Apparently the problem I'm having has never existed before and I can't find help. So when I do get it figured out, I'll make sure to post the solution on here in case anyone else has the same issues. You guys only care about saying how I ****ed it up. I know I ****ed it up. I don't need you to tell me what I know. I came here to see if anyone could tell me what I don't know. The only helpful suggestion I got was unplugging the solenoids and I was willing to try it. And yes I am trying to save money because I'm not a rich guy playing cool in his big lifted truck that he had other people build for him. I have built all my own trucks and jeeps and spent my own money (in case there's any spoiled rich kids here). I only wanted to learn from someone more experienced than me but all anyone can say is to take it to someone else. This community only cares about who is the biggest and fastest and not about helping the people.
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