Well, my car is in a tranny shop right now... i'm getting my 5-spd rebuilt (differential bearings prob).

I'll make sure to remind them to use GL-4 tranny oil... the thing is, I wanted to buy redline MT-90 and have that put into the fresh tranny, but someone recommended that I let them use their oil so that the tranny "breaks in". During this "break-in" period, alot of metal shavings would happen? Anyone think this is true? Either way, this is sorta better because I was reluctant to give the tranny shop the redline because there's a chance they would screw me and put regular crap in anyways... i guess i'm just paranoid.

Should I switch from their dino tranny oil to synthetic after 1k miles break in period?

 

It would be wise to use a conventional oil while the 5-speed is breaking in.

Personally, I would change at 1,000 and then continue to use conventional oil for another 4 to 5,000 just to minimize leftover metal shavings.

Then, switch to synthetic gear oil.


No matter what, taking a sample after that second change is a good idea to make sure nothing else "foreign" is in there.

 

thanks bill! So sending in a sample to Blackstone is the same process as sending in motor oil, right?

 

Yep, just give them the gear oil weight and specify it's gear oil and they'll handle the rest.