Re: transmission leak--question

[Phil & Judy Rose <pjrose@servtech.com>]

>Date: Thu, 25 Feb 1999 14:57:20 -0500
>From: "Cobram ." <cobram@juno.com>
>Subject:
>
> Phil & Judy Rose <pjrose@servtech.com> writes:
>
>>Do you think it's worth a try to drain the tranny oil and replace with
>>OEM lube?? People claim that their engine oil leaks stop once
>>they change back to regular oil, so perhaps there's good reason
>>to hope my problem is reversible.
>>
>>Phil
>
>I don't think so, especially if the viscosity of both oils are the same.
>The main cause of post-synthetic leaks is usually blamed on the
>synthetic removing the "wax"  from the dried seal.  Once the horse
>is out of the barn....   If it's any consolation, a friend of mine just
>switched his 280SL (Merciless Benz) to all synthetic, and the only
>places that aren't leaking are where it's run dry.
[snip]

I don't happen to buy this commonly stated "waxy buildup removal" scenario.
I think it's more likely--particularly in the case of older oil seals--that
the change in lubricant may cause enough change in the seal swelling (i.e,
cause shrinkage) to start a leak. I've seen many claims that the leaks
produced by synth oil seeming to disappear when the non-synth is used
again. If these claims are in error, then I'll have to rethink things. But
enough thickness of "waxy buildup" to make a difference in oil sealing is
hard for me to believe.

In the case of my leaking tranny, I realize that both old and new oil are
"synthetic". But they are possibly very different, chemically, in a way
that may matter to the seals. Anyway, that my thought.

Phil

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