<VV> Other Vehicles With The Same Gear Lube Requirements

[eamsquared at comcast.net]

Bob, 
My thinking is that my M21 in 1972 should be the same as the Muncie M21 for mid year Corvettes so that if GM recommended GL-5 for 1972 then it should be OK for midyear Corvettes and Corvairs also unless there are material differences between a 1972 M21 and a 1965 M21.  What do you think? 
  
By the way, the NCRS article also concluded that GL-4 was the way to go for mid year M21's. 
  
Erich 

----- Original Message -----

From: "BobHelt" <BobHelt at aol.com> 
To: eamsquared at comcast.net, "VirtualVairs" <virtualvairs at corvair.org> 
Sent: Saturday, April 11, 2015 5:34:05 PM 
Subject: Re: <VV> Other Vehicles With The Same Gear Lube Requirements 

Erich, 
This is what makes understanding all the specs so difficult. 
  
MIL-L- 2105B preceded the GL spec listing. When that list was selected and published, the B version of the spec was converted to GL-4.  But the later C and D versions of that spec were converted to GL-5. Thus if one were to miss the change from B to C/D he would certainly think that GL-5 was the correct lube for these transmissions. 
Bob Helt 
  
In a message dated 4/11/2015 1:56:40 P.M. US Mountain Standard Time, virtualvairs at corvair.org writes: 


I am not making a recommendation here but only pointing out the fact that GM recommends GL-5 gear lubricant for my 1972 M21 whereas GM recommended MIL-L-2105B gear lube for the Corvette M21 in the mid sixties which was the same spec used on standard transmission Corvairs in the mid sixties.  Take it for what it's worth. 
  
Erich Meyer