No, nothing falls out, but it can be difficult to remove and require some careful prying.

Shweeeeeet!!! Good to know.
It's info like that that makes alllllll the difference for a learner like me. THANK YOU!

I did this last weekend and the how-to made it easy - thanks again BobRoy and DonB :)

A day in the freezer and a coating of ATF allowed the new valve to slide in without a hitch.

Two things I would add:

Vaseline is fine as a substitute for assembly gel if it's not in your inventory (confirmed by Transgo) and;

Torque figures:- TSB307-03 stresses the two different torques for the small & larger headed VB bolts.

Well done....

Well, I spoke a little too soon.

I finished all the other jobs on this PM schedule, so I was ready to start the car and complete the trans fluid fill.
The motor fired up on the button as always. OK, lets cycle the gears. Shift lever wouldn't come out of park, although solenoid clearly actuating.

Despite Don's clear pictures, I somehow managed to jam the shift mechanism. I was careful to ensure that the pin was in the slot when refitting the lower VB, and all seemed free and OK. Unfortunately, I didn't check again after I'd torqued up the VB bolts.

All it needed was the bolts slackening and a little gentle wiggling on the selector valve then all was well.

Seems I'm the first to get this wrong, so I'm claiming thehttps://cimg6.ibsrv.net/gimg/www.jag...4c5b867ac9.png of the week award. Upside is I've got the first flush in early :D

For anyone following, please check this while you're doing the final torquing on the lower VB.

Might I ask here which of the "early" transmissions are prone to this failure? Was 5hp-24 the number on all of them but early serial numbers need this upgrade while later ones do not? Or do later cars have entirely different transmissions in them? Or am I stating this wrong? Looking to buy a early 97 or 98 XK8 and must be on lookout. Thank you.

They're all the 5HP24.

There's a chap in the UK who rebuilds these boxes as a hobby: he's a wealth of information. It appears that an uprated A-drum was introduced late 2000 as a running change:
https://www.jaguarforum.com/threads/...18/post-522653

although I'm not sure if the modified main pressure valve was introduced at the same time. This TSB on member Gus' site is relevant:
http://www.jagrepair.com/images/Auto...%20ZF5HP24.pdf

Sonnax also produced an oversize replacement, akthough that needs reaming capability.

To actually answer your question, the 6HP26 was not fitted until the advent of the 4.2 (2003MY) so I'd treat an early XK as a candidate for one of the above modifications.

I guess my 04 xj8 4.2 had the 6hp26 then. It seemed balky from 1 to 2 but upwards from there it was always smooth. At risk of hi-jacking this thread, I will mention I came to this one after seeing info on X27 sub forum where I asked whether a person is smarter to buy a late XJS with 4.0L inline or early XK8. You can get them for about the same money. People on there referred me here about the trans issues in XK8. But what trans is in those last X27 six cylinder cars? And what bad behaviour do they exhibit if any? Thank you for this helpful info which I will track down on those lnks.

Take a look at the XJS forum, and perhaps drop a post in there:
https://www.jaguarforums.com/forum/xjs-x27-32/

'Passionate' may be more apposite than 'smart' for those of us running older Jaguars, although end-of run cars usually have most of the issues sorted.

Transgo O-rings
 

What is the difference between scarf cut O-rings and sizing O-rings? Do the sizing O-rings go over the scarf O-rings on the Transgo Valve before you put it in the freezer? Please, someone explain.

Yes. Put the sizing rings on/over the scarf overnight before installing. The day of smear with assembly goo and quickly slide it home into the valve body. REMOVE the shrinkers first - of course.

Oh... The sizing rings (I would guess) are of a different material and NOT to be used in the application of the valve in a hot trans thru a million hot and cold cycles and the huge pressures you will find in a valve body... The scarf (if that's the name) are suited for this purpose...

Don't worry about the difference. Just use the rings transgo says are the ones FOR the valve.

I was hopeful this procedure would cure my trans issue but it did not. I have a 1st gear slip from a stop, then bang into gear. It only happens when the trans is hot. If I lightly feather the throttle it will go into gear just fine. Any ideas on next steps?

TJ

How many miles?

It might be the early signs of a failing A drum. The Transgo is to help prevent A drum failure by reducing the spikes in pressure that are believed to cause the failure along with the origional A drum design. If it had already started to fail the Transgo wouldn't help.You will often get a check engine light with the failure. I don't recall the error code off hand. Whould need to do a search to refresh my memory but I don't have the time this morning.

See image. My understanding is/was that either the A drum failed,,, or it has not. I'm sure there could be situations of weakening and in some cases fractures, that its just a matter of time no matter what steps are taken, but (from what I understood) if the seal is still good (a large Oring I think) and the drum is structurally sound and intact - even IF you were getting pressure spikes the transgo product should save the day - and heartaches...

It's, according to transgo and what I have read, a good preventative, intervention and solution which will completely avert failure when caught early.
https://cimg0.ibsrv.net/gimg/www.jag...6fc89c83da.jpg

Thanks for the replies. The car has 125k. No trans error codes yet. When a accelerate after a complete cool down(overnight), I hear a metallic whirring in 1st as well. It goes away after a few min of driving or if I accelerate more gently. Does this indicate A drum damage?

I appreciate the help.

TJ