Lubricants for 4 speeds

[Todd H 26112]

Re: back in my drag racing days for better shiftin

Interesting insights.

Doesn't GM offer two(2) synchromeshes, one is a synthetic at ~$20 (12346190)
and the other is a conventioanl at ~$9 (12345349)?

Pennzoil/Quaker/Havoline make a 'Synchromesh' fluid marketed for GM/DC and theirs all appear to be identical to each other in every detail of the product specifications they provide. Don't know about Havoline but not surprising w/ Pennzoil/Quaker merger. I believe this is a conventional or perhaps blend but not synthetic. I 'thought' these might be the same as the 12345349. No gear oil weight is given but I surmise it to be equivalent to about ~75W-85 kinematic viscosities provided.

[Mike M.]

Re: Reback to drag racing

john: enjoyed the dragster photo. although i've done some crazy things in the past, i'd have to bump my head real hard before getiting in that critter. regards and be careful. mike

[John H.]

Re: Reback to drag racing

Mike -

Yup, "bumps your head" pretty good anyway if you don't remember to plant the back of your helmet against the cage when you nail it off the starting line; lotsa fun, though

[Todd H 26112]

Re: back in my drag racing days for better shiftin

(missed this earlier...)

I want to say I was referring to pitch velocity(?) or pitch line velocity(?) but I was reaching back in my memory cobwebs. I seemed to recall this had an affect on sliding or noise or something like that but likely an error on my part.

Yes, in theory an involute gear tooth has a perfect rolling action but in transmissions my observation is that a modest degree of sliding may occur at the very beginning and ending of tooth mesh upon initial contact. Do you have any specific transmission examples of perfect rolling involute teeth thru the entire mesh cycle? Or are you saying that in general all manual transmission have a pure rolling action thru the entire mesh including the beginning and end?

While my post was oriented towards transmission gears I am under the impression hypoid gears in differnetials do indeed have notably more sliding action than a transmission and thus the reason for the APIs GL-5 designation. Is there another reason for GL-5 being being oriented for axles? What can happen if a GL-4 is used instead?

I'd like to hear more about this if you care to expand,
Thanks!