I am getting noise from my '99 XK8 that sounds as though it may be an indicator of an impending A-Drum failure that I noted in a previous thread. I say impending since there is no code indication nor is there any clunking, hard shifts, or other mechanical indicators of the A-Drum failing, just a noise that several Forum members say sound like an indication of an A-Drum failure.
The TransGo "fix" for this transmission is a pressure restricting valve replacement (with new o-rings) kit that can be installed without pulling the tranny.
For any Forum members who have installed the kit, can you tell me if that kit is installed before any other A-Drum symptoms beside the noise are evident, will the TransGo kit likely eliminate the noise and the failure?
I have been considering the kit installation along with a transmission service -- drop the pan and replace fluid with proper ZF-rated ATF and a new filter/pan -- and would like to know if the kit is a permanent solution to the A-Drum problem.

 

I replaced the pressure valve in my 97 with the ZF upgrade and did not experience any A drum problems, but I was always careful not to accelerate until the first gear was engaged. I also changed the filter and fluid, but never considered all that to be a permanent fix.

Several members have reported failure of rebuilt units which supposedly had upgraded drum and valve body, both here and on the XJ8 forum.

 

I installed a Sonnax upgraded valve body. Just replacing the valve piston and o-rings may not do it, but it might depending on the wear. Mine had actually worn a ridge inside the bore where the piston moves and I think the piston would catch on that ridge occasionally, there would be a second or two delay and then it would go into gear with the slight thud, particularly in reverse. I think that's whats hard on the A-drum. Luckily I had read these forums and knew to quit driving it till I got it fixed. That was 20K miles ago. Sonnax has a special jig that they use to ream out the bore and install an oversized piston that's engineered to restore the correct pressures. Removing the valve body does not require removing the transmission, just the pan. I'd suggest to take the valve body out, open it up and inspect it before you order a kit. But it was a relatively easy job.

 

I did install the Transgo pressure valve in my '99 after my first earth shatter, tire chirp, slam to first gear when I discovered the valve body problem.
Rare occasion the valve sticks now. When it does, nothing radical. I am pleased with results.
I have been driving my XK8 for two years now. ( not daily driver) Ultimately an overhaul will be in the future. The valve is giving me time.
Insure you use the right fluid, follow proper procedure for fluid change. It does make a difference and has helped in stretching the life of my ZF trans. Hope it helps.

 

It won't hurt to install the Transgo but it is no guarantee. When you remove the pan look for metal fragments or filings on the magnets. It will give a indication of A drum failure.