I have been doing some research on transmissions for my 98 xj8. I am looking to adjust how smooth it shifts. It's not really bad, but I am reading that it is the same transmission for the e38 bmw's. I have had a few of those and the only way you can tell they are shifting is by looking at the tach.

I drove several jags and this one shifted the best by far. It was the only one I felt was acceptable...but if it could shift like my old bimmer, that would be top notch!

Is there any way to adjust shift quality in the 98 trans?

 

No adjustment, hardware or software that I am aware of but my '02 XK8 is really amazing, without looking at the tach you can never tell the shift points unless you have your foot in the engine compartment.

Much smoother than a couple other Ford cars I have.

 

How about software, I know the BMWs from 98-99 with these transmissions had to have trans software updates that got rid of hard(er) shifters. Do these cars have something like that?

 

I found one related to harsh shifting (below) but I think I remember one that applied to the '98 -'99 cars that called for a reflash of the TCM. I have the entire TSB if anyone wants it or it is posted on the Xk8/R forum here:

https://www.jaguarforums.com/forum/s...ad.php?t=25334

You might try AllData. They have a TSB index that gives a one sentence description but not enough to totally understand the issue/solution.

I had a VERY harsh down shifting issue with an '00 XK8 but it up shifted perfectly. The torque converter did not release from lockup when a down shift was called for. The problem was the TCM and replacing it fixed the problem.

TSM 307-14

DATE 08/03

V8 XJ Series/XK
MODEL
2000-02 MY XK Range
2000-03 MY V8 XJ Series

VIN
A00083-A30644
F00103-F59525

Shift Quality Issues/Harsh Engagement With Engine Cold- ZF 5HP26 - Install New Transmission Control Module

 

I had the fluid replaced on my 01 XJ8 4.0 and it shifts so much smoother than before. Previously it shifted smooth apart from one or two notches, but now is like silk! I had it done at 88000 miles. S.