Kevin Rhodes wrote:
>
> Hello all,
>
> I recently swapped the howling differential in my Spit for the one from my
> parts car - seem to have lucked out - the replacement makes no noise at
> all, and no nasty clunks. However, today I had to adjust the rear brakes,
> and noticed that after driving for 45 minutes or so, the differential was
> very warm - not quite uncomfortable to touch. Was a 60 degree day. Is this
> normal? I can't say I have ever touched a differential immediately after
> driving, but it seemed kind of warm to me. Definitely full of oil too
> (Mobil 1 synthetic gear lube) - I checked the level just to be safe.
Freddy's probably okay. <smile> For the sake of reference, presuming you
don't have a contact temperature gauge handy (few of us do), if you can
touch the surface for several seconds before the heat becomes
uncomfortable enough to remove your hand, the surface temperature is
around 160-170 deg. F. If you can only touch it for 1-2 seconds before
you have to remove your hand, it's about 170-190 deg. F. Beyond that, I
suppose it depends upon how thick-skinned you are. <smile>
Remember that the differential essentially has no cooling apparatus, and
it will trap heat more readily than a component which can remove that
heat. Most ordinary hypoid gear oils are able to run consistently at
220-230 deg. F., without degradation. The synthetic you are using is
probably good for many degrees higher than that. More importantly, I
think, would be big temperature differences from one portion of the case
than another. For example, if the nose of the pinion were at a greatly
higher temperature than the rest of the case, that might indicate that a
pinion bearing were becoming troublesome, or that the ring gear/pinion
mesh were too tight and causing additional friction.
Cheers.
--
Michael D. Porter
Roswell, NM
mailto: mporter@zianet.com
`70 GT6+ (being refurbished, slowly)
`71 GT6 Mk. III (organ donor)
`72 GT6 Mk. III (daily driver)
`64 TR4 (awaiting intensive care)
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