Hi guys, ive just returned to owning a beautiful Jaguar after having a Merc (that I hated)..........unfortunately the XJR ive bought appears to have a strange transmission fault that the members of lesser forums cant give a clue about.....can you!!

ok, in a nut shell the car starts and drives fine until its warm, about 5 miles of town traffic, then the orange light shows on the dash and the message is gearbox fault and it lock in gear.

Usually there is no sign of it happening, but some times you feel a definite thud from 2nd to 3rd (I think) and then the light comes on..........

Turn her off and back on and its gone but usually returns by 3rd gear (not always tho!)

The two codes ive pulled are p0715 (gearbox speed sensor inoperative)
And p1797 which depending where you look is either neutral switch on the gear selector or stuck in 4th gear..!

Im leaning towards it being an electrical fault as its not always there.......also ive just ordered the dip stick so I can check the fluid level as im not sure if she has a slight leek which will have taken its toll over time.
can anybody throw any light on what the cause and repair might be??

Thanks guys.

 

can no one throw any light on this very common problem??

 

Common problem?

Have you checked the electronic connection from the selector to the gearbox? The fault is a leaking seal where the loom plugs into the side of the box, and there's an updated seal to fix it.

You do know that the XJR is fitted with the Mercedes gearbox not ZF...

 

Yeah i know its the merc box, oddly the Jaguar handbook i have list different fluids and components etc between the xj8 and the xjr but lists the zf box with no other listing for the xjr.

Do you happen to know where i can get the part number for the bush.......im not saying my local Jaguar main dealer is crap but when i phoned up last week to ask what ATF the box took i was told to just put Dextron 2 in it!!!..........i didnt of course, i dred to thing what would have happened if i had!, i rang another Jaguar dealer who cringed at the thought and gave me the correct number.

 

Hello Howie, I have exact same problem with 2000 XKR P0715 from code reader.
I have checked Merc websites and there is instruction vid on youtube but cant find anyone who has replaced parts on a Jag. The parts would be about £250 from ebay but it would be a waste if it didnt cure fault. Hope you get it sorted.
Thanks

 

The XJR has a 'Dual Linear Switch' at the gear selector & I understand that if this isn't correctly aligned then the gearbox can throw up spurious faults.

As this switch tells the gearbox ECU which gear/driving range you've selected, it needs to be correctly aligned to the selector lever, otherwise the gearbox ECU will get confused if it 'sees' the car moving & the gearbox working-yet a misaligned switch is saying that you haven't fully selected a driving range from the gearbox.

Other than that I don't know, as the XJR Merc gearboxes are usually pretty reliable & it's the XJ8 ZF gearboxes that cause most of the problems.

 

Hi
Look at post# 3 - Sean B mentions
"the electronic connection from the selector to the gearbox? The fault is a leaking seal where the loom plugs into the side of the box, and there's an updated seal to fix it."

I found these other threads on the roadfly.com forum about the XJR Transmission W5A580 plug adapter leak fix (guide bushing). Nice DIY with part numbers, photos and advice:

first one gives part numbers and pricing - Look at post# 12
XJR Transmission and symptons

This one has photos and instructions - Look at post# 21 through # 31
XJR Transmission and symptons - Page 2

You should be able to get a seal kit from an online auto parts UK website.

Here is a PDF file I created from the JTIS Repair Shop manual on Transmission Harness Electrical O-Ring Seals R&I

https://www.dropbox.com/s/mkldsod1ft...ls%20R%26I.pdf

I also found more information in the AUTOMATIC TRANSMISSION NAG1 LX - SERVICE INFORMATION Manual (similiar Mercedes Transmission) - Diagram and part descriptions

https://www.dropbox.com/s/aviry2c07w...Diagram%20.GIF


Jim Lombardi