I got a 99 Disco with 99k miles and the trans lately will slip out of gear and then back into gear at around 50MPH. It acts like it is trying to bypass the next gear for a higher one. any thoughts?

 

I have had a lot of experience with ZF trannies. I can tell you that they typically are good or bad as far as their condition. Start by checking your fluid level, too much is just teh same as none at all in that it will create a situation where things dont happen as they should. With the added benefit of generating an overpressure condition that has the potential to blow seals. start with the fluid level(back of the block passenger side should be a big yellow dip stick.) check it with the engine and tranny cold and the shifter in nuetral(DONT FORGET THE PARKING BRAKE)you have to kind of be quick about the in and out when checking the level with the dip stick but careful to seat it all the way when going in for a sample. ZF trannies are pretty much bulletproff as long as you rub them with a diaper, but miss one birthday or valentines and next thing you know its inviting its mother to live with you.

 

Now that said. Audiworld forums have some great info on ZF automatic transmissions and troubleshooting its worth checking out. Thankfully uou are lucky had your vehicle been one year newer you would have the sealed gearbox and its a PITA to set the fluid level. Trust me on that one. ....

 

If you have a D1, they have a locking torque converter. It locks right around 50 (52 I think). It will feel like you are kicking into overdrive, but if yours feels like it is slipping, you may want to look at the TQ.

 

Maybe should clarify, do you have a D1 or 2?
Have you checked the fluid level, if it full, brown, smell burned or is the fluid red?
Get back to us and quit driving it till you get this resolved.

 

Title say 99SD, do I am guessing it is a D1