Moved: GL4 or GL5 for69 transmission?

[mbp]

Hello to all. I wondered what is the proper fluid for a 69 four speed transmission? Confused over whether a GL5 is going to hurt "yellow metals" and not help with the synchronizers over time? I understand that GL4 has less extreme pressure additives but is GL5 necessary for a 69 transmission? The owners manual mentions the visc. but that's about as far as they go. Plus any specs in 1969 may not exist any longer.
Just wondered what others used? take care and thank for ypur help.

 

[Riley P]

Hey mbp! Great question asking about which fluid to use. Have you decided on a choice?
I'm trying to think of what I used in my 66 Chevelle but I don't think it was anything specific.
Hopefully there aren't any acids in the GL5 that could hurt the metals but it's good you are looking into it. I know about being cautious because the trans in my 2000 uses paper blocking rings where they moved up to carbon in 2001 so I've heard not to use synthetic with mine, however, you get opinions from all over the place.
If no one has answered yet, send Manny a message (manny@dasilva) and ask him what he uses.

 

[mbp]

Hey mbp! Great question asking about which fluid to use. Have you decided on a choice?
I'm trying to think of what I used in my 66 Chevelle but I don't think it was anything specific.
Hopefully there aren't any acids in the GL5 that could hurt the metals but it's good you are looking into it. I know about being cautious because the trans in my 2000 uses paper blocking rings where they moved up to carbon in 2001 so I've heard not to use synthetic with mine, however, you get opinions from all over the place.
If no one has answered yet, send Manny a message (manny@dasilva) and ask him what he uses.

 

[mbp]

Hi. I decided to go with a Redline G4. After looking at different sites and the specs and benefits of G4 vs G5 I went with G4. The G5 has properties and benefits such as more slipperiness and is required for hypoid gears, but that isn't needed in my transmission and in the case of slipperiness not a good thing. Most of the manufactures say they counter those with an additive, but if not needed then why bother. I feel somewhat better knowing that the G4 will be easier on any "yellow metals"in the transmission. I'm sure the G4 will be better than what was first put in there 47 years ago.

 

[Riley P]

Good to know! I still wish I knew what I put in the Chevelle but I sold the ol' girl last year.....

 

[CorvetteRon]

I used a synthetic oil made for manual transmissions in my '76 several years ago.
No problem.

 

[XFIRE82]

good old 80 or 80-90 gear oil , GL4 , Your GM dealer has GL-4 part [HASHTAG]#89021672[/HASHTAG]