Jaguar Forum banner

97 XK8 transmission bump

2292 Views 8 Replies 6 Participants Last post by  steve308
I have a 97 XK8 with 100k miles covered. I can see by the service history that it had a gearbox change at 67K miles (5HP24) by an indipendent concern but I've no idea on exactly whether it was a reconditioned unit or a second-hand one.
The problem I have is that it takes a few seconds to engage reverse gear and if I put the power on a bit too early it goes in with a bump. It behaves itself in all the forward gears all the time.
I've read on here and on other forums that its a good idea to replace the fluid/filter but I'm wondering if the problem isn't worth chasing. A recond box may be perhaps a better idea?
1 - 9 of 9 Posts
Most 5HP24 transmissions built before August 2001 will have had the original 0501 208 317 F-brake piston replaced with the updated one (0501 212 967) due to the original piston seal material wearing badly, allowing it to leak. I wonder if that's the case with your transmission?

Another possibility is that the two phosphor bronze bushes in the sun gear drive sleeve, which act as a seal for the C-clutch circuit, are worn.

When ticking over the pump doesn't produce enough flow to overcome the leakage so the clutch doesn't engage but as soon as the engine revs are lifted the extra flow engages the clutch with a bang. Is the problem worse when hot than cold?

See less See more
yes - you need a new gearbox. Its the first sign of a failed clutch I think.

Its a well-known phenomena for that gearbox. It is possible to fix, but automatic transmissions in this country are not really a thing that anyone really opens
I would agree, that is likely to be something worn out. Mine was similar between 2nd and 3rd before it failed completely. Though also there is also a rotary microswitch in the J gate that can wear out and stop the gearbox engaging reverse easily/quickly, though it doesn't usually engage with a bump, just sticks in N. Worth checking as cheaper than gearbox, though still lumpy.

I would opt for a refurb of existing, at least you know its history. (A new one is about £7,000 fitted). If you are looking for someone to crack it open, I had mine refurbished by Surrey Jag Centre. They send them out to a place in Croyden they have used for years... They can just refurbish the gearbox for about £1,500 or also the torque converter and all other parts for £2,500 ish in VAT from memory. From my reading around you don't quite get the gold standard refurb offered by a place up in Scotland who completely re-manufacture the box, but its pretty good and probably in keeping with age and value of car and much cheaper.

I had a couple of hitches with mine (my XK8 was always problematic), but as ever SJC sorted me out amicably and I was pleased with it overall - it worked perfectly after for several years.
See less See more
Thanks for all the imput on this gearbox problem. I do have another box in my garage. I've no idea what that drives like. perhaps I should give that to a transmission repair shop for a re-build while mine is still driving.
Steve where are you? Its not on your profile. I know a very good gearbox workshop in my area.
Hiya Frank. I must do something about my profile!
I'm in Kent Frank. Quite a distance from Malvern unfortunately. There are a few transmission shops near me but I have yet to do some research on who and what is the best place to put the job to. I don't usually need to use the trade much as I do all my own service work but auto transmissions are not one of my talents!
It looks to me that one of the previous owners has had a second hand unit fitted some time ago but I think that that is not a good idea as we can see here. Just need to find a good, trusted repair shop. Steve
Dartford Transmissions are a ZF specialist and carry out oil changes and refurbs etc. Worth a call.
Thanks for that P700DEE. I'll give them a call. Steve
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.