Gear Oil for "New Process" 5 Speed

[SuperHawk]

Hi Everyone,

I want to change the transmission oil in my 64 champ 3/4 ton with "New Process" 5 speed O.D. The shop manual says to use 90wt hypoid oil if temp is below 32 degrees, and SAE 140 wt hypoid gear oil if temp is over 32 degrees.

The shop manual does not specify whether I should obtain GL-1, GL-2, GL-3, GL-4, or GL-5.

Hopefully there is someone with knowledge and experience out there in fourm land who could make an accurate recommendation to me.

Thanks,

-Larry

[FarmMotorSports]

GL ratings are NOT like API standards "higher is better". GL ratings are for application to be used in.

GL-5 was made for the automatic final drive found in some modern cars....

Gl-4 is for HYPOID gear transmissions.

Most all the other GL ratings are for low impact, non syncro applications.... GL-4 would be my choice.

But, lets see if anyone else has different feeling about this.

[StudeRich]

GL-5 for Automatic final drive? [:0] New cars have Automatic Differentials? [:0] [:0]
I am pretty sure the Transmission in a Transaxle would use ATF!

I have no idea what that is, certainly NOT an Automatic Transmission! GL-5 is used for Standard and limited slip Differentials!

Most of these early Manual Transmissions with brass syncromesh rings are usually best without the EP (extreme pressure) additives which Gl-4 has some of, so Gl-1 is usually preferred.

StudeRich

[leyrret]

Believe it or not most manual transmissions once called for 50 wt motor oil. Even larger truck transmissions. If you don mind the expense use 50w synthetic transmission lube, it will probably work best.. I use it in my ZF 5sp(it calls for syn ATF) and shifts fine at all temperatures.. I also use it in the transfer case and auxillary transmision. I never use gear oil in manual transmissions though it doesn't seem hurt them. They usually shift better with lighter oil especially when it cold. Gear oil in a ZF will effect synchronizer operation.

[hotrodstude]

most manuals today use atf.this is because the clearances are so much tighter than the older trans.older trans have greater clearances and need heavyer oil.i still would use a syn 90w-140w in an older trans.

2006,f-150,2x4,v-6,5-speed manual,8ft bed, will post stude info when i get it on the road.

[leyrret]

Newer smaller manual transmissions call for syn ATF, larger truck trans Eaton etc. all use syn 50 trans oil with syn gear oil in rears.
I know NP435 and BW T-18 in my old Ford called for 50w motor oil( I have the owners manual), though everyone puts gear oil in them. ATF will give you better mileage as will the syn. as it thinner. Older road ranger and large spicer called for 50 motor oil, but again everyone put gear oil in them. In older trans I don't think it makes much difference what you put in them, I think the syn is better oil and the lighter will shift better when it's cold.

[StudeRich]

It's great that you all told Larry what to use if he owned a non-Studebaker or something with something nick named ZF???????? [?] [V]

But all he wants to know is the GL grade and weight of Manual Trans. gear lube for a New process heavy Duty Truck 5 speed Transmission! [:0]

StudeRich

[leyrret]

NP 435 is a New Process Transmission. Very close to your "Studebaker" NP540. New Process called for 50w engine oil. The point of all the rest is you can put about anything in them. Many on this forum seem to profess a infinite knowledge of just about anything mechanical so I just assumed most would know that ZF is a brand. My apologizes for assuming too much.

[laughinlark]

I put Sta-Lube synthetic in my 59 one ton 5sp od about 8 years ago. I believe it was 85/140. It made for better shifting. The thing with syn's is leakage. If your seal and gaskets aren't quiet up to par, there will be a little seepage.

Gordon

[leyrret]

Your right about that. If there is a way out syn. will find it.