Rebuilt 4-Speed, what are you guys using for gear oil?

I was going to use 90W synthetic gear oil but wanted to hear from the experts. What are you guys using?

Do not use synthetic lube the old style syncros's work better with plain old dino oil. Penzoil syncromesh works good and Jamie Passon has a special blend that works too.
Gus

This is what I'm using.
Sta-Lube GL4

http://www.brewersperformance.com/proddetail.php?prod=GL4SL

Me too.

I also use the sta-lube but make sure you use gl4 most parts store gear oil is gl5 which can harm your syncro's

That is what I'm using now in my NP 833O.D. trans

The Sta Lube says it`s 80w90. What is the weight of the Pennzoil syncromesh ?

I did a quick check on the internet and a few people are saying NOT to use Penzoil Syncromesh in cars made before 1992 while others love it. Same with Sta-Lube although I see more positive feedback. In 1992, I was using ATF in my A833s.

Penzoil Syncromesh No complaints in 3 A833"s for me

Found this on a site. The guy making this claim seems very knowledgeable based on other posts:


That is very true, greg.


We have had this discussion many times in this formum about Synchromesh vs synchromesh and I am surprised so many people have NOT done any searches before or researching before entering into these discussions.

Then there is Pennzoil Synchromesh, a brand of synchromesh fluid by Pennzoil, a 9.5 cSt (about 0W30 weight) MTL with a GL-4 addpack.

Then there are the GM Synchromesh fluids brand which are 10.5 cSt (about 5W30 weight) MTLs with a GL-4 addpack.

I developed this list to assist in the selection of synchromesh-type fluids so please help me understand what is so confusing about it?

Penzoil syncromesh In Mine

Why use such a light weight GEAR oil in these 4-speeds?
Ease of shifting?
Less gear friction?
Or it contains "syncro" in name?
Why not just heavy gear oil?
Not like many, if any, will be driving them in the winter.

It shifts better and its not all that light when you consider the factory suggests ATF for cold climates.

Any 75W/80W-90 as long as it carries a GL-4 rating...NOT GL-5. We use Amsoil MTG in our shop and have exclusively for many years with ZERO issues.

They said ATF in later years as a "Band Aid" remedy to user complaints in cold weather of hard shifts. Of course: gear oil thickens in the cold, until driven only a few miles, then works fine. These weren't designed by Chrysler to "user friendly", but rather to transfer, and withstand, heavy loads They (Chrysler) weren't concerned about long-term (high mileage) effects (wear & tear). Sure: racing OK. Less frictional losses. But any geared power transfer unit (a833, rear axle) needs heavy gear oil for best lubrication properties.

I'm going by what the Service manual suggests and they were under warranty. Is there a bulletin "They" put out saying ATF was not to be used?

I don't know if any of you guys have driven a manual trans Honda before but they use straight 30 wt, engine oil in their transmissions. They shift perfect at any temp and last 300K without any work on them I haven't tried it in my stuff yet but I have added a quart of engine oil to Toyota truck transmissions before to aid in cold weather shifting issues.
Gus