Rebuilt 5HP18 Issues

[Frank87]

Here's the situation:

Rebuilt a 5HP18 "088" identical to the 5HP18 mounted behind my M60 3.0.

I have:
- Replaced steels & friction plates
- Replaced Drum F due to wear
- Replaced inner & outer teeth cup spring in drum G (old one was cracked, no spring action)
- Replaced all O-rings, sealing rings and other parts that seal
- Replaced all needle bearings except the one in the Ravigneaux set (don't want to take the gearset apart)
- Replaced the brake band
- Re-used all other parts

As far as I know, I have correctly assembled the transmission. Everything slots in just fine and the gut of the transmission now looks identical to a fresh 5HP18 pull from a wrecker that I have laying around for comparison. That 5HP18 has not been dismantled. I only took out the valve body to be able to look at the gut.

I have installed a new torque converter.
I have re-used the valve body (which I rebuilt a few months ago) to ensure any issues can not be valve body or TC related.

I have correctly filled the transmission (added about 9 liters, still some left in the trans radiator and coolant lines)

Here's what happened:
P->R = super smooth and R always functions
P -> R -> D or P -> D = super smooth and first gear functions normally

I started to drive in D. First gear had no problems, no noises, no vibrations. Feels better than the removed tranny probably due to the new torque converter.

Shift 1->2 = increases RPM and the shift is somewhat violent (but the second time it did 1->2, it appeared to be ok).
Shift 2->3 = Excellent (and I mean, EXCELLENT)
Shift 3->4 = "Getriebe notprogramm" = trans emergency and the car comes to a stop. Engine keeps running but for some reason, the trans causes the car to come to a complete stop. After this stop, even when playing with the lever, I have no action in D.

When the car stopped, I moved the lever to R, felt a somewhat violent jerk and drove back in R. R functions normally under all circumstances. After a while, after starting the car again. The transistion from P to R was again super smooth and R still functions.

I do not smell anything strange. No burned clutches or dirty ATF smell.

Does anyone have any idea what I have done wrong? I know this transmission uses a gear with a sprag inside of it but if I remember correctly, that gearwheel can only be mounted in 1 way so that the sprag is always blocking the way it has to.

All clutch packs had end play within ZF standards.

[632 Regal]

Never did a 5HP18 yet. Sounds like your leaking pressure somewhere. A seal could be reversed causing all this.

LOOK at the gaskets, holes may not be the same as the originals. If a port is sealed it cant work. Look especially at this if this trans was used with other car makers.

[shogun]

I would remove and rebuild the valve body once more, maybe something wrong there.
Pay special attention to the gasket between the 2 plates. Would be good if you have the old one still, because there are 2 gasket styles
gasket 1056 327 100 5HP18 old Version
gasket 1056 327 110 5HP18 new Version

The new version can be used as replacement for the older version, but the older version cannot be used to replace the new version. I reconfirmed that with my authorized ZF repair shop from where I got the gaskets. The shop manager told me that he once mixed up these gaskets and had trouble. Then he changed to the other version and all shifted smooth.

Same applies to the 5HP30
gasket 1055 327 093 5HP30 old Version
gasket 1055 327 102 5HP30 new Version

[Frank87]

The VB has been used for 15.000 Km. in the older transmission. No issues. I could rebuild it but I think I did not screw up on the valve body.

[whiskychaser]

I know this transmission uses a gear with a sprag inside of it but if I remember correctly, that gearwheel can only be mounted in 1 way so that the sprag is always blocking the way it has to.

IMHO, if you had put the sprag in the wrong way round, your gearbox would be in little pieces now.

I know you may be thinking brake band too but can you engage 2,3 and 4 with the lever?

[Frank87]

For those of you interested in this story.

A few months back I removed this failed rebuilt trans and opened it up. Clutch E was totally fried. At first, I thought I did not smell any burnt clutch pack but when I opened up the transmission, It smelt like a manual drift car after a hard day of drift-work and E was completely gone.

I also noticed that I could barely move the input shaft (should be moveable) and it became moveable once I removed the brake band tension mechanism. I think the brake band did not loosen up as much as it should due to a mechanism that puts too much pre tension on it. This means it's a matter of strengh when the band and a clutch fight over who wins. The E clutch lost. All other clutches were in perfect shape.

New clutch plates and all required sealers were ordered and the transmission was rebuilt. Did not take alot of time. I played around with all kinds of band tensioner mechanisms that I had from scrapped transmissions untill I had a combination that precisely matched ZF's tolerances.

Transmission has been mounted last week and shifts great. It is literally "like new".

The only problem I now have, is that:
- When I use a valve body that I have never touched, my 1 -> 2 shift is not really smooth
- When I use a valve body of which I have done the main channel plate and in which ALL springs have been replaced, my 2 -> 1 is not smooth and gives me a light jerk (see this topic: http://www.bimmernut.com/forum/showt...question/page3)

So I have a valve body related issue which I am trying to solve. The rest is done.