Looking at a 2002 XJ8 with 65000 miles, the vin# has it with 3rd. generation tensioners. The thing that makes me leary is the transmission, do all of them go bad early on?
Do trans.fluid changes help or is this a really crappy transmission?

 

It's an excellent transmission, but not really able to handle the V8 in it's earlier form. It appears ZF made some improvements, one of which is the upgraded main pressure valve.

It may be fitted to cars of 2002 vintage, but I haven't seen any definite proof. I have not, however, read of any 2002 or later A drum failures. Someone please provide information if that is not the case. I also recall reading that ZF beefed up A drum at some point.

It's relatively inexpensive to install the newer pressure valve and many of us feel that changing the fluid and filter is important. Jaguar now recommends doing so.

My transmission is still working smoothly and a friend has a '97XK8 with over 130K mi and no transmission problems. These are both 5HP24 cars.

 

I would recommend regular transmission fluid changes, especially if you do a lot of short journeys. When my transmission failed on me the mileage was roughly 130K. I've now got a 2002 XJ8 which I'm doing a semi restoration on, and one of the main things I'll be getting done is fitting the modified Transgo valve. I've read nothing but good things about it. I've had to order it from the Powertrain warehouse in NJ, but luckily they ship to the UK and the price is beyond reasonable. It's a small price to pay for piece of mind.

ZF 5HP24 5HP24A TRANSMISSION PRESSURE REGULATOR VALVE KIT TRANSGO 5HP-24-PR FITS BMW A5S440Z JAGUAR AUDI ROVER - The American Powertrain Warehouse
TransGo ZF 5HP-24: 5HP-24-PR

 

I took a 99 transmission from one of my parts car and put into a 98 xj8. Before I did the exchange I decided to put an upgraded A drum and pressure valve in to try to eliminate any future problems.

Upon taking the A drum out of the transmission I found that there was an extra spring in the drum, part #974 in zf5hp24 diagram. The A drum was in perfect condition and the transmission had almost 100,000 miles on it. I was going to try to do some research on this but haven't had the time.

In my opinion the extra spring would mean it will take more pressure to engage the clutches. Maybe ZF way to help eliminate the pressure spike problem from the defective pressure valve.

I use to put double springs in the Yamaha 1300cc engines in my sons race car. This was to help reduce the clutch slipping under high acceleration. It made the clutch pedal harder to push but he only used it from a stand still position.

I don't know the data but we're the 99 on transmissions more reliable than the earlier models or did I just have a transmission that hadn't failed yet.

And as to the original post I would do the pressure valve upgrade. You can do it without removing the transmission. While you have the pan off for the upgrade look for any metal fragments in the pan. If there are any you might need to upgrade the A drum.

 

My 98 seems to be okay. I changed the tranny oil and it now seems to be better. At first, when wet, the tranny would throw loads of codes. Wouldn't change gears (stay in 4th, no matter if driving innercity or extraurban) and would just bang... That is now more than a year ago and the tranny doesn't show any signs of giving up anymore. No more codes thrown or so...

 

Depends on driving style too. I am at 123,700 miles on mine (2000 MY). I have noticed a little harsh shift here and there. Still going strong though. I am going to change the whole lower valve body for a rebuilt one (sometimes they can crack and replacing the PRV just isn't enough). And I am going to replace the fluid and filter also. I would NOT suggest doing a power flush not the tranny. Just a simple drain and fill.

 

1999 XJ8 VP 100,000 kms. So I just ordered the upgrade valve (Thanks for the link above), the filter, gaskets etc, as well as fluid. I was going to have tranny shop do the valve and filter and do a fluid exchange using the trans cooler lines. Not suggesting a machine flush but the shop says it will be using trans pump to do the work. Is this frowned upon and if so why. I cant see mixing fluids then driving for a bit and drain and fill.

Could I have an opinion as I am doing this once the valve arrives in the mail. Thank you

 

I think using the transmission pump method works. I did multiple drain and fills, five total.

 

Thank you for the note, I am trying to avoid multiple drains because I am getting too old or timid to crawl under the car with jack stands. I want it done it one fell swoop but want to be assured Trans cooler method is effective.

Great forum, as a new Jag owner very happy I found this site.

 

My '03 died at 49k miles.

I am currently looking at upgrading the transmission and doing a fluid change in the next couple of months when the car has its 60k service (the "new" used tranny will have 75k miles). Assuming that the new transmission is still in decent shape without valve body cracks or A-drum damage, is there much of an advantage to ordering parts in addition to the pressure regulator valve that Stu 1986 linked? This would include the valve body kit and/or a reinforced A-drum.

 

I have owned two(2000,2001) both well over 100,000 miles & have experienced zero transmission problems.