XJS gearbox problem

Hi folks. I have an 88 V12 XJS 5.3 auto which has been running great until yesterday. Whilst driving home it suddenly started to rev whilst in gear at 60 mph and then no acceleration. When my speed dropped down to about 20 mph it started to drive again but won't change gears. Its now stuck in 1st and won't change at all but goes like a rocket. Ive checked the fluid on the dip stick and it shows full and there are no oil leaks either. The gearbox is the standard auto box that was fitted to the car when new. Any ideas before I start pulling it apart (aside from scrapping it. lol)

Bob

Reply to
nerodude
Loading thread data ...

Hi, The transmissions shot. Youll have to have it rebuilt or replaced. I had the same symptoms on my 83 Buick Lesabre wagon, it was $600 (US) to rebuild. No idea what it will cost on a Jag. You can try a junkyard replacement. I did that with the Buick the first time the tranny went out, it only lasted a year. The rebuild has been going since 2000. Regards, Nathan

formatting link

Reply to
Nathan Bates

It's a standard GM T3 Hydra-matic 3-speed automatic. Commonly found on 70s & 80s GM cars. It can be diagnosed with an oil pressure gauge by a 'competent' mechanic. (You won't find one at AAMCO or most transmission swap-out shops. ) Ask your normal mechanic who he/she would recommend. It's not hard but you have to know what you are doing... ie. GM manuals help. Fastest is, of course, a transmission swap. Just because it's a XJ-S shouldn't make it any more expensive. It's actually one the few things on the XJ-S that can be said about '-)

Reply to
bill

Reply to
WayneC

"nerodude" a écrit dans le message de news:WVWic.185$1f2.51@newsfe1-win...

Hi Bob, First of all, change the oil and clean the filters ( thers is a filter in the gearbox lower sunk) I had the same problem with a Rover and this was the solution for another 20

000 miles Good Luck Georges
Reply to
Aaxoo

Actually it is a GM TH400 in a proprietary case that will not fit to an older Borg Warner V12 or even the 6 cylinder engines.

These units do not use a throttle pressure cable; instead a vacuum module is used. If the vacuum source to that module becomes disconnected, or the module itself fails, you would have a hard time getting a shift since the transmission thinks you have full throttle.

Another thing to check is the tightness of the valve body to the trans., I can't tell you how many shift issues have been resolved by retightening the mounting screws. I will also mention seeing a couple of governors that had some debris jam the shuttle. However just as mentioned, the first thing is to check pump pressure.

Cheers,

Blake

Reply to
DieInterim

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.