Newbie needs help. Maybe someone of you has experience with TJ gearbox repair... My wife and me own a Magna 3.5 built 10/2000. Engine and gearbox have 130,000 km on the clock. As she drives through a roundabout last Wednesday the gear jumped off. Since that we can't drive. The motor is running flawlessly. When switching from P to D or R revs are raised slightly, but the gear is not jumping in. On the search for the error I am already arrived at the shaft at the top of the gearbox. Shifter, cable and the other things are probably ok. When I start the engine and shift the gears at the shaft nothing happens. My question is: Is there a maybe in the background working electronic control unit, which prevents the gear engagement? Or is it a mechanical failure in the gearbox? Maybe a broken torque converter? Are there any weak spots in this Magna gearbox? Any hints or clues?
Sorry for the funny English, but I'm from Germany.

My (limited) knowledge would suggest to get hold of a MUT communicator to discount the possibility of an electrical (solenoid etc) not working properly.
Apart from that, the manual says most likely (non electrical) causes are failure of underdrive clutch or valve body.
Have you consulted the maintenance manual for additional info?

Link is here... Sect 23 is for your gearbox.

http://www.aussiemagna.com/forums/showthread.php?t=99122&highlight=workshop+manual

Sounds a lot like the old wave spring issue common to the earlier model 4 speed autos. Spring breaks, gets sucked into the filter then jams up the pump.

Forget about MuttII and wave springs. Wave springs do not stop boxes from working

Test fluid pressure, remove a cooler line and start motor. If little or no fluid comes out then oil pump has been damaged.

Is not worth repairing, get a good used box, we do have them but freight to wa is expensive, best try and get one locally

Forget about MuttII and wave springs. Wave springs do not stop boxes from working

Sorry mate, the info I had was from Transmission Digest, where they showed some examples of wave springs shattering, passing through the filter and getting ingested into the pump (4 speed only).

The website link doesn't work anymore though, so I can't even show the info. Was this bollocks all along though?

I understand where you are coming from and yes this can often happen. The other big cause of these things is the planetary gear set fails and the schrapnel just eats the inside of the box