hicrop10 Posted March 15 Share Posted March 15 I will be placing the transmissions back in my b87 and was wondering what oil I should put in them and the rears? Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/ Share on other sites More sharing options...
Joey Mack Posted March 15 Share Posted March 15 Im curious just to learn. My guess is 80W90. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571405 Share on other sites More sharing options...
Joseph Cummings Posted March 15 Share Posted March 15 I use 85W-140 in the trans and rears. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571406 Share on other sites More sharing options...
hicrop10 Posted March 15 Author Share Posted March 15 Tks, that’s what I throught just wanted to be sure. Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571409 Share on other sites More sharing options...
Geoff Weeks Posted March 15 Share Posted March 15 I haven't seen a HD transmission that wouldn't do well with SAE 50 oil. It is what most call for, has the aprox the same viscosity of 90 GL,none of the additives needed for hypoid gearing which is not need in transmission and can attack brass. It also handles heat better then GL Axles are a different story, there I would go with gear lube. 80w-90. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571413 Share on other sites More sharing options...
Joseph Cummings Posted March 15 Share Posted March 15 2 hours ago, Geoff Weeks said: can attack brass. There is no brass in the transmission he has. I run the 50 straight mineral in my trans that have synchros like the Fullers 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571425 Share on other sites More sharing options...
Geoff Weeks Posted March 15 Share Posted March 15 (edited) didn't say there was, just pointing out that SAE 50 is the preferred transmission oil. In the old days, GL-1 was all they had for transmissions, Now GL-1 is almost obsolete and SAE 50 can be used in place of it with better heat tolerance, there is no down side to using it place of 80w-90 GL1 and no advantage of anykind in using GL-2 though 5 in transmissions. Most, but not all GL2-5 are "yellow metal" safe, but again, no advantage to using GL over SAE motor oil. If you look at any transmission spec sheet written in the last 40 year or so SAE 50 is the preferred, and GL-1 80w 90 as "acceptable" as long as oil temp is kept below 220 or so. Hypoid and Amboid gear sets require Gl in the higher designations, but not transmissions. H & A gearsets have a very hard wipeing action when the gears mesh, unlike spiral bevel and spur gears. EP additives are needed in these set to prevent the oil film from being wiped off the gears by the sliding action of how they mesh. EP additives have drawbacks when used where they are not needed. Edited March 15 by Geoff Weeks 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571428 Share on other sites More sharing options...
Joseph Cummings Posted March 16 Share Posted March 16 5 hours ago, Geoff Weeks said: no advantage of anykind in using GL-2 though 5 in transmissions. I have an pneumatic pump and hose reel on the wall and I buy it by the 120 pound keg. The 50W is in a 5 gallon pail with a hand pump. Not to mention the 85-140 is already what's in all the older Macks All of it's getting crazy expensive. The kegs of 85-140 are about 400 bucks now, the synthetic that is in the new trucks is close to 1,000. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571459 Share on other sites More sharing options...
Freightrain Posted March 17 Share Posted March 17 I had a conversation with a Schaefer representative. He recommended their 239S, 50w lube. The original GL1 is no longer around. $165 for a 5 gal pail. It is what I put in my rebuild. These transmissions due have brass bushings on each gear. Previously I did use 75w-90 or 85w-140 from AutoZone. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571533 Share on other sites More sharing options...
seyser Posted March 17 Share Posted March 17 I used 80w-90 in the trans and rears of my R model. Quote Link to comment https://www.bigmacktrucks.com/topic/75287-oil-in-transmission/#findComment-571564 Share on other sites More sharing options...
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