[Shadofax]

On the motor oil, I have not heard of anyone doing that, and personally I would not for the following reasons:

I just got finished rebuilding a manual shift one to replace my auto Tcase..

Issue 1) The pump assembly in there may have an issue pumping the thicker oil. This will eventually heat the internal shaft/plantetary, etc. and cause it to seize. T case would likely not be rebuildable at that point and it will leave you stranded.

2) the whole Tcase looked to me like it totally relied on the pump and splashing for lubrication, so I think viscosity of lubricant is critical. I'm not sure how well the thicker oil will be able to get up to lubricate the various bearings.

You mentioned whinging, it may be that your tcase is about to give out in any case. You really ought to pull it and rebuild before it lets go. How many miles on it? Are you aware of the internal oil pump locating arm issue?

 

[Shadofax]

It may have quieted it down, but be prepared to have to put a new T-case in there very soon. if the bearings were that noisy your just putting a quick band-aid on it

Totally.

And yes, 150miles nothing. check back at 15k that's what I'm interested in. 150 miles can be a distance trip to a wheelin' place, that's nothing. And if it spills guts on the highway and you are screaming mad at the tow bill, be a man and own up to it to spare others. I can't imagine the oil pickup system was meant for this thick of fluid. Time will tell.opc1: