Transmission Oil?

Daryl Smith · Post by **Daryl Smith** » Sun Sep 11, 2005 4:40 am

What oil are you using in your transmissions?

When I had my transmission built I asked the tech and he suggested a light oil (as light as I'm comfortable with). Says some new OEM transmissions use regular motor oil, and some even use ATF.

Talked to my brother about it, and he says he heard the same thing and put ATF in his S10 p/u 5 spd several years ago with no noticeable difference???

I am considering a synthetic ATF or maybe a synthetic 20/50 motor oil.

What are your thoughts?

Chris Coker · Post by **Chris Coker** » Sun Sep 11, 2005 7:43 am

Try Redline MTL in your transmission. I know lot's of roadster owners who use this oil, and I used it's higher viscocity brother, MT-90 in my race transmission. I think you'll be very happy with it.

Jorge022770 · Post by **Jorge022770** » Sun Sep 11, 2005 4:32 pm

I appologize for getting in the middle of the exchange here but.....back in the days when I asked what kind of oil to put in my 4-speed tranny, I was told to put the same gear oil I put in the differential........and I did. Did I get the wrong advice here back then?

Or is this something acceptable?

Thanks Guys

Jorge

Daryl Smith · Post by **Daryl Smith** » Sun Sep 11, 2005 6:40 pm

Jorge,

Up until the last week or so, I would have used the same oil in the differential and transmission (probably 75-90 wt gear oil). That I think as been the standard for many years.
This idea of using lighter oils in the tranny is something new to me, so that is why I asked the question here.
Wondering if anyone else has had this suggested to them and if anyone has had a go with the lighter oils. I'll have a search on the internet and see what I can find... And look up Redline "MTL" and others.

Thanks for the note Chris.

Post by **dbrick** » Sun Sep 11, 2005 10:09 pm

I used 85w90 in both, no noise. Only thing I know is that if the oil is too slippery, the syncros will not be able to grip the gears to match speeds while shifting causing grind/hard shifts. Any gear oil should be fine for this, don't know about motor oil. There was a post here about this earlier this year
Dodge used Dexron auto trans fluid in the manual transmissions and rear axles all through the 70's and early 80's, and had a bulletin to replace with 85w90 gear oil only if there was gear noise.

DELETED · Post by **DELETED** » Sun Sep 11, 2005 10:31 pm

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