Gents, Hope you're well and keeping safe. Seeking some guidance as am sure another fellow member has experienced the issue I am encountering with my XJR.

My vehicle is depicting erratic shifting between 1 and 2nd gear, it often goes up to > 3000 RPM before shifting from 1st to 2nd, and it has a hard downshift to first. This only occurs when the vehicle has been running for 45 minutes to 1 hr and when I am at low speeds within the neighborhood and at low speeds again forcing the use of 1st and 2nd gear. It has circa 92,000 miles and the transmission service was done with the proper spec fluid about 3 months back when the rear min seal leak was fixed.

I have a very competent mechanic and he hooked up his reader and we drove the vehicle for an about an hour last night. No codes came up, the transmission temperature etc. was fine, but he did feel the erratic hard shift after about 45 minutes or so. He believes the issue is not electrical, but mechanical.

I wanted to ask if you know of a distributor that sells the transmission parts for the XJR X308 Mercedes transmission here in America. I see the part number on the web as NNC4400CEE, but not sure what Mercedes transmission part# it maps to. My mechanic is open to rebuilding it and did a complete rebuild on my Porsche, just looking for your guidance on a distributor for parts and the correct Mercedes transmission part# to source the necessary items.

I would also welcome any input on all weak problem areas to be tackled during the rebuild process.

Thanks in advance for your input.

 

The Mercedes part number will not help because I doubt the bell housings are interchangeable (Mercedes vs Jaguar).

 

When the mechanic hooked up his 'reader' were you looking at TCM data or ECM data? (ie. could you see what gear you were in etc.?)

See the TSB for explanation of the CAN bus limitations of the W5A580 TCM. (related to OIL TEMP)

 

@ Motorcarman - Many thanks for your input.

Just as a reference point for others if they encounter this issue: https://www.jaguarforums.com/forum/x...hanges-222909/

I will be pursuing the fix and will post back in a bit.

 

Another thing you can try is doing a hard reset, drive it again 45-60 minutes and see if it behaves the same, better or worse. I feel that will help narrow it down to an electrical vs mechanical issue that way you (and the technician) know which way to go. I know you said the technician thinks it’s mechanical but it’s a simple test and it could provide valid information on how to approach the next step.

Just my 2 cents.

 

NNC4400CEE appears to have been a rebuild kit (NLA now). "transformermike" (Ebay) is selling kits for Jaguar 722.6 (https://www.ebay.com/b/Transmission-...03/bn_20369140) so you can check with them about what exactly you need.

Otherwise, Master Kits sold for the Mercedes 722.6 are also easily available (https://www.transmissionpartsdistrib...ngines-78004a/). A Mercedes 722.6 kit (internal parts) is probably the same as that for Jaguar 722.6.

 

The above inserted link to Ebay does not seem to work. This is one of the "transformermike" offers for XJR: https://www.ebay.com/itm/722-6-W5A-3...8AAOSw-xVZ71Vn