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| | | Forums66 Topics128,109 Posts1,056,569 Members48,448 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
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For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Apr 2005 Posts: 1,971 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 1,971 | I have been searching trying to find an answer to the question of what type of oil to use in manual transmissions and rear ends when they use yellow metals (bronze) bushings in them. The sulfer acids in the oils will work to corrode bronze in them, so people are searching for GL1 oils (which seem to be carried at NAPA stores) because they are afraid of their bronze bushing disintigrating in their old trucks and tractors.
So many forums repeat not to use GL5 with yellow metals. I found that to be mostly untrue.
I said mostly, not entirely.
It seams that most GL5 lubes are now compatible with yellow metals IF it has a rating of "MT1".
Early GL5 lube may have been corrosive, but, most of the new GL5 lubes have counteractive agents to any sulfers that reside in the oils. The new GL5 has the "MT1" rating. Look for that rating and you should be OK.
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