4th, 5th gear ratio codes after rebuild

BG lly 2500

New member
Aug 9, 2021
21
1
3
I just rebuilt my 04.5 allison 1000 with a merchant auto work series kit, their valve body with transgo installed and their single disk converter. When I'm at low rpm in 5th gear doing 50mph and I barely give it throttle I can feel it start slipping and then it limps. If I'm doing the same thing and I give it 50% throttle it will kick down and go. If I get on highway it's fine, all through the gears really nicely. If I get on it hard it holds but it feels a little weak, like it's slipping slightly. Any ideas what this could be?
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,327
364
83
Central OH
Pretty much haha. Better call the people you bought the gas from to use their squeegee, not the station down the road who knows what they're doing.

IF Mike or someone else comments, it'll probably say "we have no idea what you did or didn't do correctly when you built it, better tear it down".
 

BG lly 2500

New member
Aug 9, 2021
21
1
3
I checked and did everything according to the ATS book and the directions provided. The C2 mod, the pump spring, the hole in pump plate, clearances within spec but C2 was on the loose end .080. I'm taking it out now to swap some old thicker steels to get clearance closer to .060 on C2. This is all I know to do.
 

BG lly 2500

New member
Aug 9, 2021
21
1
3
I really would appreciate someone's insight/knowledge on this. I'm in a really bad spot or I wouldn't of even did this on my own.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,686
232
63
Fullerton CA
The first problem here is you think you did everything right. You didn't list the code #'s. You installed the C2 piston mod when you should have been advised not to. You bought your kit from a company that doesn't give you support on their product. You don't know if in fact the valve body is ok. We don't know what you did or didn't do correctly and neither do you.
 
  • Like
Reactions: Hoser

Hoser

Active member
Jun 19, 2016
233
30
28
Farmington, MN
That is the single biggest hurdle to overcome in order to fix anything, admit that you did something wrong. It’s so frustrating when I try to help guys and they will not admit that they did ANYTHING wrong, even though they have no idea what they’re doing, and the fact that their stuff isn’t working proves that they did SOMETHING wrong. Realize you made a mistake, and be open to input from those that are more knowledgeable than you are, that’s the first step in getting help from those who know what they are doing. If you are pigheaded nobody will help you. Not trying to call the OP out, or be a prick. . . . .
 

BG lly 2500

New member
Aug 9, 2021
21
1
3
Yes I obviously did something wrong. I did follow directions though. I do not know exactly what I'm doing but I think I can handle it. I've almost got the transmission back out. The codes have are P0734 and P0735. I have another trans, 03 that I can take the C2 out of to disregard the mod if that is what I should do?
 

BG lly 2500

New member
Aug 9, 2021
21
1
3
I asked them about the valve body, they said it's ready to install, has transgo shift kit installed.
 

BG lly 2500

New member
Aug 9, 2021
21
1
3
Ok C2 clearance is .097.... checking with feeler gauges and that snap ring in bottom ring. How am I going to get .030?
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,320
1,606
113
Mid Michigan
You should be calling Merchant and asking them for help. Like Mike said, we arent there and have no idea what you did/didnt do, so anything we say is just a guess. It sucks, but its the truth.
 

BG lly 2500

New member
Aug 9, 2021
21
1
3
Assume I installed everything right and my C2 clearance is too big, what are my options? I have 7 fibers and 8 steels.
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,327
364
83
Central OH
Post pictures. What does the apply plate look like? Anything burnt? Did you pull the c2 piston to check the seals?

If Merchant stood behind their kits, they should be able to walk you through any issues or get replacement steels if clearances aren't right. In my experience, the c2 pack is usually on the loose side of you just throw in what the manufacturer sends in their box.
 
Last edited:

BG lly 2500

New member
Aug 9, 2021
21
1
3
Looks like it's the same as stock. Exactly the same amount of steels and fibers and they look exactly the same except old fibers are completely gone. Steels are same thickness, Within .002