On Mon, 8 Apr 2002, Dwayne Cooper wrote:
> I got the '74 up on ramps and found out that one of my differential mounts is
> completely separated from the frame (the stud appears to have pulled clear
> also). While inspecting, I found that theres a pretty good oil leak somewhere
> in the differential itself. It's dripping from the bottom of the casing and
> finding its way over to the left brake drum and dripping out of the bottom
> there. I've lined up a welder to install/reinforce the mounts, but it now
> looks like the differential itself needs attention. Would a local
> transmission shop be a good source for a differential rebuild? Or should I
> buy a rebuilt unit from TRF?
A competent shoppe can do the work, but if your goal is to replace the
bearing and all that (do a "real" rebuild), then you need to be aware of
how the pinion head height is set. Without this knowledge, the job can be
rather frustrating, as you need to set the pinion head and then assemble
everything and then measure the pattern on the ring gear (the engagement
pattern) and then adjust. The adjustment is done by removing the pinion
head and adding shims.
The hard part is that the pinion height adjustment is done by adding shims
under the inner bearing race, so if you get it wrong, you need to pop the
inner bearing race out from the case and add/remove shims.
Therefore, if you don't have the pinion height measurement device and/or a
proper tool to remove the inner pinion head bearing race from the case,
you will need to take assemble/disassemble the pinion assembly multiple
times. Without a proper tool to remove the inner race, you wind up hacking
the shims up and the resulting messed up shims can effect your pinion
height.
Find a shoppe that's done the work or better still one that has the proper
tools. Many places that specialize in British car stuff will have the
proper Churchill tools or will have made suitable equivalents.
If you find that you need to replace the gears, these adjustments are even
more important because if you get 'em wrong you can/will ruin the gears
and/or the bearings.
If I were a "casual mechanic", I'd be seeking assistance on this one.
There are others besides TRF. I have no direct experience with TRF
rebuilds (except for rear hubs.)
Note: if you are leaking a lot of diff fluid, you can check the axle seals
while the diff. is still in the car. You disconnect the inner axle
attachment bolts and position the axles out of the way, then remove the 4
bolts holding the differential axle stubs to the diff. case and withdraw
the axle stubs. If the seal is "real bad", you will be able to move the
"plate" around a lot. If you find these seal to be bad, def. send the
stubs to someone that knows what they are doing - these axle stubs have
the same taper seat that the outer hubs have (keyed) and they are a reall
pain in the proverbial butt to pop apart without damaging the parts.
FWIW, I have a stack of axles with bad seals out in the garage... gotta
get around to fixin' 'em one of these dayZ.
Also, don't forget to check the proverbial diff. case vent cotter-pin
thingie. If you are getting pressure in the case, it has to vent somewhere
- this is important because TR6 diff's run pretty hot.
> Dwayne Cooper
> '74
regards,
rml
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