Hello -

My 97 XK8 with 55k miles recently started to slip between 3rd and 4th gears. Specifically, it will slip into neutral, the engine will rev, then it will upshift with a bang from 3rd to 4th gear. All other upshifts are ok and all down shifts are fine.

Any thoughts on what the problem may be?

I am going to service the tranny in a few weeks: change fluid, filter and valve body and install dip stick.

thanks

 

Also, I don't think this is relevant, but a 'traction control fail' code has come on as well as a transmission fault message. I haven't had time to do the fix on the traction control yet.

 

Charlie,

I've moved your question from General Tech Help to XK8/XKR forum.

You'll get more Views here from members with the relevant knowledge and experience of these two issues specifically on XK8.

Graham

 

The 3-4 shift is the first thing to go when a transmission is worn out.

You will get a code P0783 from memory, when it slips from 3 to 4, the bang is what causes the code to be set.

If you're lucky it's low on fluid, and a fluid/filter change with the level set correctly might fix it, but in most cases it's a rebuild of some sort...

 

yuck - dealing with my second go around with transmission rebuild. As Cambo said you'll be lucky if fluid/filter change fixes. Otherwise expect a hefty repair bill.


If you can remove/replace yourself check the DIY's here and on Gus's website. Not sure how much a rebuild would cost in Ca, but as a point of reference - I contacted Eriksson industries this week - $2295 for a rebuilt with a 1 year warranty plus $700 core charge and then freight - Eriksson Industries


In my case - I was already into the shop for $500 to remove/inspect so using Eriksson was no savings for me - looking at a $3760 price tag

 

I would definitely investigate this issue first. As you know, these systems (ECU, TCU, ABS) are highly integrated, and have inter dependencies, e.g. the ABS module provides wheel speed, etc. If you are lucky, the root cause could be that the transmission fails because it is unable to obtain a key piece of information from the ABS module, or something to that effect.

Speaking in general, the earlier car is subject to ABS module aging issues requiring re-soldering of the main power posts. The main ECU also has its own aging issues typically requiring a rebuild. There are many threads about this on this forum, you can start with the stickies. As usual, for intricate problems like this one, you have to start with extracting the diagnostic codes with a Jaguar-aware code reader. One you have them, feel free to post them so folks can help better.

Best of luck, keep us posted.

 

Chase out the traction control issue first. Start with making sure that the ABS sensors are clean and in good working order 5hp24 is a "smart" electronic transmission, and the TCU controls the process of shifting from gear to gear by controlling how much pressure is applied to clutches. The TCU also has a habit of chatting with ECU and ABS/Traction control computer via the CAN bus. If your ABS system is misbehaving, it can seriously confuse your TCU and cause all kinds of transmission-related grief.

Did you change the trans fluid and filter recently? There are some shitty "OEM" filters for 5ph24 out there. I would only install one that came from ZF in a ZF-branded box.