1995 Jaguar 6.0 V12 Auto Box

1995 Jaguar 6.0 V12 Auto Box

Author
Discussion

MackV12

Original Poster:

5 posts

123 months

Thursday 28th August 2014
quotequote all
Hiya folks. Hoping you can help me with a strange issue I have with my auto box I have on my 1995 Jaguar 6.0.

If I run the car in normal mode, unless I am really gentle with the accelerator, the gearbox will go into limp mode and hard shifts. Checking for codes I got P0751 - Shift Solenoid A Performance or Stuck Off, error code.

I dropped the auto box pan, replaced shift solenoid A and finished with an oil & filter change. It did not make any difference.

For a laugh I tried the car in Sport mode and caned it. No issue at all.

Not sure what is going on, any ideas?


ftypical

457 posts

125 months

Thursday 28th August 2014
quotequote all
Is your car trying to tell you to drive it harder???

MackV12

Original Poster:

5 posts

123 months

Thursday 28th August 2014
quotequote all
A car with a V12 6.0 engine does not need a "sport" mode. Trust me I floor that puppy and its like the millennium falcon taking off.

The sport mode just lets you start off in first gear and holds the gears longer. Normal mode starts the car off in 2nd gear, using the wall of torque method to move the car forward.

Why the gearbox should have a hangup over manual which uses less gears than sport mode not sure.

rougemont

29 posts

174 months

Friday 29th August 2014
quotequote all
These boxes are normally bullet proof and all issues usually are down to electrics. Might be worth checking/ replacing the internal wiring link lead situated inside the sump pan, these seem to go 'off' over the years, very easy to replace though you will have to drop the pan again. I had an issue with the same box on a s/c xjr hunting between 2 and 3 and this turned out to be the problem. Good luck.

MackV12

Original Poster:

5 posts

123 months

Friday 29th August 2014
quotequote all
I was told by a Jaguar expert the gearbox was toast. How come it works great in Sport mode using all the gears?!? Your assessment aligns with mine - it is electrical issue. Either the wiring harness - internal/external or the TCM.

How much was the internal wiring harness and where did you get it from?

rougemont

29 posts

174 months

Friday 29th August 2014
quotequote all
Hi, I had a spare gearbox following a manual conversion so took the lead from that but I am sure a bit of research on google (gm4l80e) will show something up, these boxes have been sold in their thousands in the US and I am pretty sure the internal harness is the same irrespective of car it was fitted to, also I found the factory cd very handy for the wiring diagrams £20 or so well spent. I assume you have a x300(305) in which case the ecu is under the passenger knee roll, worth having a quick look at connections but my money would be on either the multi pin connection or the internal lead, apologies if I am telling you what you already know! Pm if you need to borrow a spare ecu, I am based on the south coast.

MackV12

Original Poster:

5 posts

123 months

Thursday 4th September 2014
quotequote all
Rougey agree on the likely culprit being electrical. I have been driving the car round in Sport mode and still no limp mode issue. It is staying in Sport mode - much more fun anyway!

Sent you a PM as the manual conversion sounds very interesting.

The car already runs LPG, HID conversion kit, lights off the 308 (later V8), bluetooth headunit, etc, etc