I changed the gearbox fluid yesterday and when i went to drive home, all worked well until i reached 51mph when the overdrive (?) kicks in and i had clutch slip symptoms ie when i accellerate, the engine revs but the car doesn't speed up. Everything below this speed works fine.

Im praying its something simple and not a gearbox repair or replacement

 

Being as your sig says "97 XJ series", I am assuming it is an X300 6 cylinder, and NOT a V8 version, so that means you have a transmission dipstick???. If I am correct the following applies.

If you got NO dipstick then things a tad different, see the last paragraph.

Keeping with the basics of what you have played with, I would suggest the fluid level is too low.

As a quick test, add 1 ltr more to the trans, and pray some more. That 1ltr will not destroy anything, even if the trans is at "normal" level.

I always use the "cold" level as a guide and the final level is ALWAYS done after at least 30kms of driving, which means the trans fluid is now at the correct operating temperature.

The no dipstick (V8) transmissions are filled via a fill plug in the side of the trans, and the level is SET at cold (mostly), and can be tricky to get the thing properly "full". It can take 3 or more dribbles of fluid to get that thing FULL.

 

Ok thanks. That makes me feel a little better. Before the fluid change the level was at hot mark on the dipstick even when cold it is currently just above the cold mark. I need to go see my gf tonight, she lives about 10 miles away so i will put a bit more in and if nessercary stay below 50 then check it tomorrow morning.

Thanks

 

I put another litre in yesterday and did about 20-30 miles and all is fine. Thanks for the help i was really worried then

 

Once your love life settles a tad, the correct checking for the trans fluid on these is:

Trans oil at operating temp, when you get to her place is just fine.
Level ground, or as close as you can get, but minimal sloping is preferred.
Engine RUNNING, in "P".
Remove trans dipstick, wipe with a cloth, reinsert, and remove and note the level reading on the HOT scale. A little overfull will do no harm, but a little low will/can cause slippage, and that will burn the trans, and your bank account.
All this will take about 20 seconds, and then your mind can get on with the important stuff, HER.

ENJOY

 

lol id better not let her see this thread

Cheers