Changing the shift selector shaft seal on a GM400

XJ
1

Dear enthusiasts,

one of the minor issues remaining on my XJ12 HE '83 project car relates to a slight oil loss on the tranny. Every time I change gear (from P to N to D, etc.), and only then, a tiny tiny amount of oil gets lost at the shift selector shaft seal on the driver’s side of the transmission. It seems that changing the seal is a simple job with the help of a cheap special tool. At least, that’s what a whole lot of video tutorials for the TH400, which is essentially (or exactly?) our GM400, suggest, see for example:

However, Jaguar, as usual, took precautions to make this job not all too easy! There is, as you would expect, very little room besides the tranny, which means that changing the seal with the GM400 in place is barely possible. One at least would have to lower the tranny let’s say two inches or three to be able to apply the tool.

Hence, before I go for the seal kit, which implies trans-Atlantic shipping after all, I would like to ask you if anybody has already successfully completed this job whithout a major operation on the tranny. Is it possible to lower the GM400 a few inches, or would that do damage to the transmission or the driveshaft? And did someone already try one of these TH400 tools on a GM400? I’m pretty sure that this should be straight forward, but you never know until you find out – or somebody tells you who has already done it.

Regards,
Florian

2

i did my th400 out of the car, i suspect you could place a jack under the trans, remove the x-member, then lower the rear of the trans the couple needed inches.
i would remove the shift linkage before lowering, but it needs to be off anyway.

3

Might wanna unbolt the fan from the front end of the engine before doing that lowering, too.

4

Hi guys!

Thanks for your ideas. I might give it a second thought though, as it seems that the job could potentially turn into something big. The oil loss is quite marginal, so maybe I’ll just wait and see.

Regards,
Florian