5hp24 rebuilt issues

[fmugur]

As a few of you here know that I rebuilt a ZF tranny following the manual and with help from other members that were succesfull but something didn't go well for some reason with my rebuilt. I might have overlooked something in my rebuilt process.
So, the first gear is fine, the reverse is ok too but when I put it in D it does not change gears and it is actually trying to stop when it supposed to change. If I put it in the second gear manually after the first it it stopping very harsh to the point that it will brake something. If I start in 2nd it revs and it seems like part of it is trying to move the car and another part is stopping it.

I have the old tranny out I removed the valve body so I can see inside. It looks like moving the output shaft it moves the D/E brake in one direction only and not the other and the A/B clutches move only when I rotate the output shaft on the opposite direction.
Now, I don't remember how my rebuilt tranny behaves but I don't recall being the same as above. I might be wrong though and it might not be even possible but I think I could move the D/E brakes in both directions from the out out shaft.

Could the problems I have be related to the valve body only? I guess I can try to clean the VB that came out from the tranny that I just removed and swap it on the rebuilt one. But is it worth the effort?
I can remove the rebuilt tranny from the car and compare the behaviour of both on the floor and then disassemble both and compare.
Another option is to rebuilt the one I took out and swap it but how do I know if I don't run into the same problem again?

[RRPhil]

You definitely engaged the rooster-comb pin into the slot in the manual valve when you replaced the valve block assembly?



Phil

[fmugur]

I thought about that but i made sure that was in its place.

[fmugur]

What would you suggest to try next? Do you suspect to be a VB problem? Should I swap it?

[RRPhil]

As you will know from the manual, ZF recommend that each clutch pack is tested with compressed air before the valve block is replaced, to check the integrity of the seals



Rather than using a metal plate I use a sheet of Perspex which has the advantage that you can see where to put the holes!

Phil

[fmugur]

Since I didn't know what "check all the functions of all the clutches/brakes with compressed air" ment I skipped that step. I will do this on the other tranny when I will rebuild it. What does "all functions" mean? What shoul I look for? I can try to do it on the car if I take the VB out. Is that an option although there is some oil in there?

On the other hand you reffered earlier the manual valve. My main pressure valve was a bit different than the one I took out from the VB. I remember mentioning that was the upgraded version? Could that be a possible cause?

[civdiv99]

I hit mine with the compressed air when I reassembled it, but mostly for curiosity. Now only you know how you 'feel' about your work, but if 'twas me, I'd be all over that valve body and associated interfaces and connections. This trans is fairly simple in that it only goes together one way. Unless you actually missed something entirely.......

The sprag clutch or whatever it's called in there is what gives you the one-way turnability you refer to. Likely no worries. Sorry, I haven't had time to review your entire rebuild thread, so I don't know if you took your VB apart or what, but if so, start there.

[civdiv99]

You go activating you clutches with compressed air after installed and has run, you are in for a serious mess. You and everything in yer vicinity. But yeah, you can pull the valve body out (that's messy enough) in fairly short order and trigger the clutches.

Originally Posted by fmugur

Since I didn't know what "check all the functions of all the clutches/brakes with compressed air" ment I skipped that step. I will do this on the other tranny when I will rebuild it. What does "all functions" mean? What shoul I look for? I can try to do it on the car if I take the VB out. Is that an option although there is some oil in there?

On the other hand you reffered earlier the manual valve. My main pressure valve was a bit different than the one I took out from the VB. I remember mentioning that was the upgraded version? Could that be a possible cause?

[fmugur]

Thanks guys. I don't know what and where I messed up. I know I have followed what you guys did and the manual with some exceptions: no test on the clutches and I have not measure the thickness of the clutch packs under a certain pressure. But other than that I tried to be within specs. I understand that this could very well be the cause but none of you here refer to these steps as a mandatory step. Was I just unlucky or stupid to believe I can get by without these two steps.
Last night I did a valve body swap and the behaviour is the same. So, I guess I must have overlooked something on the towers but what?
I didn't test the clutches when I swapped the VBs but if the test doesn't pass I will have to take the tranny out anyway.
Now, since we need at least two cars to be functional I am at the point I have to make a decision. I can buy a rebuilt tranny or try another rebuilt on the tranny that I just took out. I am not very confident that doing another rebuit is the proper path since I don't know what went wrong with the first rebuilt.
Any thoughts on what went wrong?
As I described above, the first gear works but when I change to second it's like I slammed the brakes. Revers works well too.

[fmugur]

I just talked to Louis and he had a good point. The transmission most likely is trying to engage two clutches in the same time when I switch from first gear. Any explanation what could cause this behaviour?