When sitting a light waiting for it to change, the transmission slams into gear as I step on the gas. It doesn't do it all the time. I am wondering what is going on and if anyone else is having that problem.

 

Is it a metallic bang or just a feel able hit?

 

Lots of threads with similar symptoms if you search. Low fluid or A drum failure are the most likely causes. Slamming into gear is symptom of A drum failure.

 

If the A - Drum shatters you have a bigger and more expensive repair . Suggest take it out of service before then

 

If the bang feels like someone hit you from behind I'd second the A Drum. I just went through this in Dec.

 

How does someone address the issue after the point of recognition before the hard damage of shattering or tooth loss of the A - drum ( if there is a lesser intrusive try if the A - drum is not damaged before complete teardown if it is ). I understand the root cause is scoring and bypassing on the valve body with the main pressure regulator and the solution is to ream the cylinder up a size . But in order to get to the valve body in the lower pan requires dropping the transmission ( ? ) . I don't understand the reason why you would have to drop it . This is for a local X308 owner that may want to be ahead of the game and do the modification before it becomes an issue .

https://www.jaguarforums.com/forum/x...val-faq-48233/

 

To get the valve into the body, you unbolt the valve body from under the tranny. You don't need to drop the tranny, justbthe sump and valve body. The tranny has to come out if the A drum has fractured... And you don't up the cylinder... You up the valve (basically a piston) which is in the cylinder bore

 

ZF 5HP24 parts illustration and catalog :

http://www.e38.org/ZF_5HP24_Spare_Parts.pdf

 

Here is a thread I made showing how to install Transgo pressure valve.

https://www.jaguarforums.com/forum/x...hlight=Transgo

 

Second what Daim said. You do NOT have to remove the trans to replace the valve body. You go in through the trans pan. Mine was already out of the car so I just flipped the trans over and did it.

 

I would like to know what to buy, where to buy, and how much does it cost to buy parts and supplies for replacing the A drum. Also whatever else that would help. This will be my first time on the transmission.

 

Thanks for the information guys . With respect to the original thread starter wrd0225 at the point of recognition of the issue is there a chance that the A - drum is not damaged and can be left alone , or would you recommend replacing it ? I will look for metal in the filter and pan . I will pass the information you provided along to the 3 area XJ8 owners for the 4th one had the transmission replaced .


TransGo ZF 5HP-24: 5HP-24-PR

 

There's in-depth threads here detailing the procedure, use the search function.

 

Here is a thread that might help.

https://www.jaguarforums.com/forum/x...t=Dreaded+drum

 

wrd0225,

I have merged your two threads into one since they were both related to the same malfunction, and it reduces confusion for other members to see all the related posts in the same thread.

FYI I am having a similar problem on our 2003 XJ8. I have already installed the Transgo pressure control valve, which improved things somewhat, but I'm still getting the occasional slip-then-slam behavior, mostly when slowing to a near stop then applying throttle. My next step will be to do the A drum upgrade but since my other Jag needs a bottom-end rebuild (connecting rod bearing), for now I'm nursing the '03 by relearning my bad lead-foot habits.

Cheers,

Don

 

Don B , I faintly recall ( for this is not my transmission model ) seeing a kit that included a reamer to upsize the bore and polish if the metal is scored or scratched allowing a bypass above the regulated pressure . This would require a larger o - ring other then what is currently installed . Could be a damaged o - ring during previous repair installation being rolled or cut or wrong size . This might be your case without touching the A - drum .

 

Thanks for the tip, Lady P!

I'll do some research on that procedure!

Cheers,

Don

 

The original valve doesn't have ANY O rings, which is why bypass flow is a such a problem.

 

Another option is a rebuilt valve body.