Hello All,

I bought my 01 XJ8 about 6 months, hoping it would get me through my last year of school. Last week on a cold trip to chicago, the transmission slipped on the way back and it slammed into gear.

From there on when I accelerate from a stop the engagement will slip until it slams into gear and then it drives and switches gears normally. Reverse works fine.

From looking around on the web, Ive found it is most likely one of two things on the transmission, one of them being a cracked A drum.

I can drive it on a minimum, it really just needs to last me a few more weeks. My main question is should I consider changing the transmission fluid as a hope it will by me more time? If the A-drum is cracked will any moment of high stress simply cause it to fracture more (and more easily and then add more metallic parts floating around in the transmission?)

Any input would be appreciated.

Thanks,
Brian

 

See my informal survey results from a few weeks back concerning fluid change. My OPINION is that you are better served saving the money towards the new tranny you need, but other opinions will vary.

No amount of fluid will fix a broken A drum, not will it delay the Adrum explosion.

 

^^^agreed^^^


I have a pile of 3 tranny's that have come out of X308s over the past couple weeks. If there is no visible ATF leak don't waste the time/money on that box.


I find a good warrantied drop out and put that in. An XJ8 tranny swap is the easiest you will ever do (once you get the damn exhaust off.)


After that, change the fluid regularly. I change it on my cars every 35k (just a pan drop/filter change/refill.)

 

Thanks for the feedback, when you say A-drum explosion it has me concerned?

Is it a bad idea to continue driving until complete failure?

Thanks,
Brian

 

If you're slamming into gear...you're already past entering into the failure mode country. It ain't gonna get better. In the 5HP24 transmission A drum failure mode, the root cause is a worn main pressure regulator valve bore that causes high line pressure spikes leading to broken A drum.

The primary cause is the main pressure regulator in the valve body...the proximate result is that a high pressure spike causes the open end of the drum to fracture from the increased torque, releasing the spring clip that holds the clutch pack into the drum (these are not like US trannies with bands, etc that cost WAY more to overhaul) and causing almost exactly what you describe.

Bad idea? Depends on your definition of what a bad idea is, I guess. The bad thing is that the box has to come apart down to the empty case (or should, if you want to make sure there is nothing else wrong like metal shards and chips of broken drum floating around the case...) and rebuilt (though there are many who just pull the bell housing and input shaft/a drum out, replace with upgraded parts, reassemble, new filter, new fluid, etc and they're happy with that...). That costs $ and that $ is almost the price of what the car is worth.

Good thing is that, if the tensioners have been done, this is the other major (?) fault of this model, and, if it's any consolation, this same box in Beemers and Audis suffer the same failure, so it's not Jag-specific (lord knows, there are enough bespoke parts on these things that can cause aggida).

Just my $.02. In my case, I ate the cost, got an overhaul exchange, put it in (3 days before Christmas...yeah, the checkbook was moaning a bit...) and kept going.

 

Let's get to the root of the problem. The A drum needs to be replaced. This my 2nd one and you can see the split on the other side of drum. I learned the hard way and $6K that you should get OEM part not the one on Ebay. Next, why is this happening? A pressure regulator in the valve body seems to be the culprit. Do some research and get this checked and replaced as well if necessary.

 

I just spent $1700 getting my previously rebuilt tranny rebuilt again. The guy works on nothing but Range Rovers, Jags, Mercs and BMW's and his business is good. It takes a second to swallow the bill on a new trans but I'm on day two of mine and feel like I drive it to New York and back in total comfort. Sucks to drop the cash but once you do you'll be happy