After taking my car into the dealership last summer to diagnose what my problem was, all they could tell me was it look like the transmission oil is burnt and there's an internal fault. So they wanted to charge me $8k to replace the whole thing, never getting real specific on the details.

well I've been gone since august, so the car hasn't been driven anyway. But my dad told me last week he took it to a transmission specialist shop who did the diagnostic for free for us. Fortunately, they were able to be a bit more specific than the jag dealership. Several internal sensors were bad and the torque converter needs replaced. They said it'd be about $3500 to tear the thing apart and fix everything.

Does it sound worth it? It's an '03 STR with about 120k miles.

 

hey phaelax, have you made any progress with your problem?

I've been researching similar symptoms to what your car's transmission had in the other thread you started. Not only do I have the wheezing/sqawking sound and P0735, I've got a P0784 (4-5 / 5-4 gear load fault). Like you, only happens on the highway trying to goose the go-pedal to either drop down to 5th, or mine likes to just go to 4th instead... lower gears are just fine. I also end up stuck in 4th gear, with the gearbox fault MIL on. My oil has been changed out twice, the last time not more than 10k miles ago, with the ZF Lifeguard fluid each time.

My dealer diagnosed it as internal transmission problem (or damage), and did not recommend the TCM update as a fix which has been successful on other ZF6HP26 units. I got another opinion from a shop down the street from the dealer, who has worked on many of these ZFs, he says its internal also, and quoted me $4200 for a rebuild.

I've found a few documents that lean towards a specific valve body solenoid (EDS3) being the sole cause of this initial error, and I yet may try this $100 part swap myself. It is only energized for 5th gear. But, if the damage is done to the torque converter or any clutches due to a sticking solenoid, I'll be left with no other option than a rebuild. I'm going to ask some advice from the XK8-XKR members, so I'll start a thread over there if you want to come by in a day or so to contribute some input.

 

Have you checked the trans oil level is not low?

You've seen TSB JTB00072 and at least made sure the TCM is up to date? Bit of a long shot, though.

Even longer may be to investigate ABS sensors ... www.jaguarforum.co.uk/f27/gearbox-fault-please-help-45392.html