x300 Gearbox Problem
 

Hi
My 95 x300 has a reco gearbox which goes brilliantly...when it goes. But occasionally, after it has been driven for a while, it will 'clunk' when changing down from 2nd to first and then get stuck in 1st. After a while it will be ok again until next time. I replaced the transmission control module and thought all was good, then it happened again. Any suggestions? Are there any adjustable cables or bands on these gearboxes or is it all electronically controlled? Any suggestions would be greatly appreciated.
Pete

Welcome to the Forums.

When the Jag is sorted, please do an Intro in teh New Members Area.

Sound like you MAY have a 3.2ltr, with the XF 4HP22 NO electronic transmission????????

If it is, there is a "kickdown" cable attached to the throttle spindle capstan, alongside the accelerator cable, and easily identified. Adjustment is mentioned in the archives, and I would have it here in the piles of papers if you cannot find it. I did mine the same as the old BW65/66, by feel, we South Aussies are that good, HA.

If you have a 4ltr, ignore what you just read.

High idle will cause both tranmissions to clunk on down shift, sooooo, make sure she be at 800rpm or close to that.

Hi Pete,

Welcome to the Jaguar Forums! It's great to have you with us.

If you have a Transmission Control Module, then you must have the ZF 4HP24 electronically-controlled transmission.

Is the transmission full of the correct fluid (a good Dexron III equivalent with the correct high viscosity)?

Have you scanned for stored Diagnostic Trouble Codes that may be related to engine-transmission performance? For example, the engine torque signal derives from the Mass Air Flow Sensor and is critical for the Engine Control Module and TCM to orchestrate smooth gearshifts. Likewise, the Throttle Position Sensor signal and Vehicle Speed signal are critical.

Check the electrical connector on the rear of the transmission for oil contamination. Also check the rotary switch on the left side of the gearbox: remove the steel guard plate, then the cover of the switch, and clean the gold pads on the circuit board with a pencil eraser and zero-residue electronic cleaner. Check to be sure the screws that secure the switch to the gearbox are secure and not allowing the switch to rotate. Move the gear selector lever through its positions and confirm that the switch wiper arm is landing on individual gold pads and not straddling two pads at once (which could indicate the switch has rotated or the cable has stretched).

We'll look forward to your Introduction post in the New Member Area - Intro a MUST and please keep us informed.

Cheers,

Don

Thanks Don.

I missed that bit, beer got in the way, sorry guys.

4ltr it is.

Naughty corner for me, with the beer of course.

Hi Don and others
Thanks for all the suggestions, sorry about the delay replying. After various talks with my excellent mechanic the conclusion was that as the gearbox has been overhauled the fluid, wiring and the rotary switch are probably ok. Fluid levels are certainly ok. The fault codes were coming up as Engine Control Module, (forget what the specific number is), so my next step has been to remove the ECM and take it to an electronics whiz in Sydney who specialises in checking such things. Should have heard from him by next week so I'll keep you posted.
Certainly get some curly little problems on these forums....
Pete