When I first start my 2002 XK8 in the morning and shift into reverse to back out of my garage, it "CLUNKS" really bad. I wait until the engine idles down from a cold start, God forbid I don't wait....
Once it warms up a little, all is well. The car has around 85 K on it. It seems to run and shift well, but I am getting worried about this.
Do any of your Jag,s do this?

 

I don't think that's normal. Mine certainly doesn't do that.

 

This is exactly the description of what wound up being a recall on certain models of the Lexus GX mid-sized SUVs about five years ago. The cause was eventually determined to be a faulty (warped) drive shaft. A new-and-improved drive shaft was designed and built, the recall was issued, and the affected vehicles were fitted with the new drive shaft at Lexus' expense. It did indeed solve the problem....

The Lexus forum community always called this problem "The Clunk"....

 

No real knowledge on your issue but there is a rubber coupling between the transmission and the drive shaft that almost universally has some level of deterioration. A dealer tech diagnosed my clunk as that when it was the TCM causing harsh shifts.

Worth a minute on a rack to shake everything and see where the noise is coming from. That is not normal.

 

By warming up a little, do you mean the rpm's come down and the shift is smoother, or the engine and tranny warm up to temp and the shift is better?

 

Is it like a creak? Kinda like when you watch those shows with those old wooden ships and inside you can hear the wood creaking? I get something similar to that when it's cold as far as shifting at first into reverse. Once the car is warmed up it goes away.

 

This rubber coupling (called a Jurid - item 2) has been a weakness since the XJ40 design.



Although the XK8 Jurid doesn't appear to suffer the same frequency of splits as the saloons, most do show wear with an accompanying loss of smoothness in the driveline.

Worth examining both the Jurid (item 1) and the Universal Joint (item 3) for wear and ensuring the securing bolts are all tight:



The later 4.2 models have a different design of propshaft with a centre bearing:



The front shaft is thinner (collapsible in the event of accident) which may put less stress on the Jurid and make it last longer.

Graham

 

Thank you GGG for the information regarding the driveshaft. I did not know about that. However, once my car warms up a little bit, both the engine and the transmission, it shifts just fine. It is as though the fluid is to thick when it is cold, but thins down a little as it heats up. Or maybe a hydraulic line is not primed after setting, and then slams home the firstfew times. I am just guessing, I don't know squat about automatic tranmissions.

 

You have a very nice car collection! Maybe it's time for a fluid and filter service on your "sealed for life" transmission. At least check the level. Seems driveshaft would make noise whether the engine is warm or cold.

 

There's a TSB about that kind of problem in your model year.


A/T- Harsh Cold Engagement/ Poor Shift Quality

TSM 307-14

DATE08/03

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

VIN
A00083-A30644
F00103-F59525

ShiftQuality Issues/Harsh Engagement With Engine Cold- ZF 5HP26 - InstallNew Transmission Control Module

Issue:
On some 2000-02 MYXK NA vehicles and 2000-03 MY XJ vehicles within the above VINranges, customers complain of the following transmission shiftquality issues, most noticeable when the engine air intaketemperature is between 20°C and 30°C and when the engine coolanttemperature is below 40°C. Under these conditions the engine speedwill increase to 1300 rpm for an initial 30 seconds and then reduceto 1000 rpm. During the initial period when the engine speed is at1300 rpm, the customer may complain of the following conditions:

^With no throttle application the transmission hesitates and thenthumps into gear when shifting from neutral to drive.

^ Withno throttle application the transmission hesitates and then thumpsinto gear when shifting from neutral to reverse.

Action:
Incase of a confirmed customer complaint of the above condition onvehicles within the above VIN ranges, install a new TransmissionControl Module (TCM) as described below.

Note: If any DTCs arestored in the TCM or Engine Control Module (ECM), carry out anyrepairs as a separate Warranty Claim and before installing the newTCM.

WORKSHOP PROCEDURE
1. Install new TCM (see WorkshopManual, JTIS CD ROM, section: 307-01A, SRO 44.15.32).

PartsInfo
Revised TCM LJD 2401AC

 

That TSB seems pretty spot on to me. Mine does go up to around 1300 then down 1000 then to normal idle 600rpm. Although mine is P to R, not so much N to X. Once it's warmed up then it's not so pronounced. I'd like to confirm the TSB's statement that it's only happening during the initial 1300rpm period too, as that's only about 5 seconds in my case. I'm looking on the JTIS CD to see how easy it is to install a TCM, they have some on ebay and tom's foreign auto for 50-100 bucks. This forum discussion may help too: http://forum.roadfly.com/threads/114...-Gearbox-Fault