Hi everyone. Not so long ago my gearbox started acting strange, it slips sometimes when starting to drive, it shifts roughly and today I got GEARBOX FAULT message, no limp mode or anything like that, just gearbox fault comming up for few minutes and then dissapearing again...
So what is this? forward drum? some pressure valve? gearbox ECU? or?.. it still works (guess not for long) it shifts rough from gear 2 to3 or 1 to 2.. not shure, and when braking it comes back to gear 1 roughly...
what actions should I take? where could I order the parts for this gearbox?....
any help would be appreciated

 

model and year?

if it's a ZF 'box, you're probably looking at an A drum replacement if it's slipping. The next thing is a hard shift and limp home unfortunately.

 

sorry, forgot to mension car year make... it's 1998 xj8...
can there be more problems if the drum goes down completely? or gearbox just goes to a safe mode?

 

probably I will not be lucky and it can not be just insufficient transmission fluid?

 

Hi
Many on the forum have just had the forward drum replaced. But when I had our ZF5HP24 transmission rebuilt the ZF repair shop owner said he also found excess wear in the valve body.

He believes that this causes excessive pressure to be put on the poorly designed forward drum. The result is that the forward drum fails (cracks apart).

We were able to drive our 01 XJ8 for several days before it started to go into Limp mode. But I do not recommend it. Those broken pieces from the forward drum could cause more damage to the other hard parts in the transmission.

Jim Lombardi

 

is there any way to check if it's valve body or anything else? or the only way is to take apart the box? would OBD tester show any codes?
if I'll take the box out, change the drum (if it's broken) how to know if it wont happen again if the problem is some valve body? my gearbox was in techs hands once, when I bought the car it was with gearbox fault. I don't know what was then but I know it's not funny paying a fortune for fixing it and having same problem after two years of driving.
so I'm trying to get more info on anything about it. Thanks to everyone that has responded.

 

Hi
After we had our transmission rebuilt and reinstalled, we did have another gearbox fault about a week later when we stopped for a stop light.

I called the ZF repair shop and the owner told me that there is probably some air in the transmission unit. Recommended adding more AF fluid.

When the transmission is rebuilt, the rebuilder fills it with ATF and bench runs and tests it on a machine.

More ATF fluid needs to added after the transmission is reinstalled and the metal fluid lines are connected.

I bought 3 more bottles of ATF and had our mechanic go through the filling operation as many times as needed to make sure it was full.

I have not had any problems since then. The rebuild and reinstall was 8 months ago.