Jaguar Repair: 87 xjs v12 transmission, height measurement, drive shaft

Question
Recently had transmission rebuilt at nationally advertised franchise shop.

After returning it for further work because of noisy converter and vibrations in the driveline felt in the cabin, I have it back.

the converter noise is gone, but there is still a very noticable whine/whirr in low gear -- like a low geared truck tranny. Also there is noticable but not severe vibration, particularly at around cruising rpm of 2500 rpm.

When the shop returned the car the first time, they had issues with the transmission spring mount, they said the spring was weak. So I ordered new spring, they put it in. I am wondering if the vibration is normal drive line vibration transmitted to the cabin by an improperly installed transmission mount -- maybe too firm or with no play at all? Is there a height measurement or play measurement for the spring mount?

I have the car running great save for this vexing problem.

G

Answer
Hi Garry,
A wine in low range has to be inside the gearbox but there is a problem with Jag transmission mounts. If you look at the spring mounting plate you will see that it rides on two rubber side mounts and they get weak and sag. If they do look like they are sagging downward that can be the cause of the vibration. It is usually noted on acceleration. To test if that is the problem I temporarily raised the rear of the trans and drove the car and if the vibration changes or goes away then you know that is what is wrong. It has to do with the alignment of the gearbox and drive shaft.
Howard