Gear oil- GL4/GL5

From what I am beginning to think I'm understanding, it is exactly the limited slip modifier that causes part of the problem with using GL-5 in transmissions. I am about to dump and refill my T14/D18/Warn OD combination with some GL-4, that is as soon as I can find some. I have had problems with shifting without that 'crunch' sound ever since I put in the fresh Herm rebuilt combination (yes I had Herm go through all 3 gear boxes).

The OD especially is difficult to get a clean shift without the momentary grinding noise that I called the 'crunch' sound. I have learned to shift by slipping the stick into neutral before stepping on the clutch, then adjusting engine RPM to what I think is about right for the next ratio I want to select, then completing the shift. Essentially this is the same thing as 'double clutching', I just get into neutral by slacking power enough to let the gears disengage.

This is kind of a long-winded way of saying I think I am experiencing the same thing others have described, the GL-5 lube I am using is too slick to allow the synchronizer blocking rings to do their job.

Don

 

What did Herm tell you to put in them?

 

If someone has a source, specific brand name and part # of a GL-4 gear oil I'd order some.

I checked with all the local parts stores, Napa, Carquest, O'Rielly's etc., and GL-5 is all they carry.

I'm using Chevron RPM Universal Gear Lubricant..SAE 80-90W, API GL-5/MT-1..seems to work just fine....got it at a Chevron station....

 

I don't recall him giving a recommendation, but then I didn't ask. I had just bought a 5 gal bucket of Valvoline GL-5 85-140 and planned to use that.

From now on, that stuff gets used only in an axle for me.


Don

 

I saw this in one of the stores. It does not offer a GL number but it claims that it is formulated for syncro's and yellow metals....I have not tried it...

http://www.pennzoil.com/other-car-p...luids-and-gear-oil/manual-transmission-fluid/

 

Found this note on the Novak web site concerning the T-90 and it's variants...

"When filling your T90 with gear oil, we recommend that you select a conventional mineral oil or a para-synthetic in lieu of a full synthetic oil. Properly assembled manual gearboxes do not have the thermal strains seen by combustion engines or hypoid gears. Synthetic fluid in these gearboxes, while not harmful, is probably an economic waste.

Hypoid gear oil is sulphurized higher than transmission oil and can be mildly corrosive to the non-ferrous alloys used for synchros, bushings and thrust washers in these transmissions.

An 80W-90, API-GL5 or MT-1 rated fluid is very good. Some claim faster shifts from using a 50W engine oil in their transmission and we do not consider this to be contraindicated unless you operate your vehicle in a very warm environment."

 

Not in anyones lifetime that's reading this thread.

 

I thought that too....My old jeep did not have the best of routine care, as far as fluid changes etc. over it's life so far...In fact I would guess we never drained and refilled the transmission..we have owned it since 1962.....and it really shifts just fine. I've drained and refilled it twice since June, and drove it some in between just to loosen and get rid of some of the crud...I filtered the draining oil with a fine mesh paint filter, and caught next to nothing....and it still shifts just as well as it always has.....

 

Might want to check closer. Says for certain GM and Chrysler transmissions. Ours are neither.

 

Yes I know, but it is not a blood transfusion....

 

Spicer axle manual (D-30 and D-44, but I bet it will cover the 25/27 also)
http://www.scribd.com/doc/47507492/Spicer-Axle-Maintenance-Manual

In the section before tools are the lubrication specs.

Also, find a good API GL1 oil for the Tranny/TC. The higher the GL number the more Extreme Pressure modifiers are put in. Trannys and TC don't need them because they are not under high pressure loads.
80w-90. Unless you are running around the Yukon or northern Canada, where you want to run 50w in the winter time.

 

DO NOT USE FULL SYNTHETIC LUBE IN THESE TRANSMISSIONS.
Yes, I shouted on purpose. Have not seen parts degradations caused by using it but have seen lots of shifting issues caused by it. I've seen many instances if customers using synthetic then complaining of shifting/grinding issues (after they were told to NOT use it. Disassemble transmission, nothing wrong. Switch to the correct oil, no problem. Several times I've seen the same issue and the customer flushed out the synthetic and switch to proper lube and gee, problem went away..

Most GL-5 gear lubes say limited slip compatible. Few actually have limited slip friction modifiers added. What that means is the lube won't attack and degrade the clutch friction material, not that you don't need to add the friction modifier.


Sent from my iPhone

 

Is this what we want for GL4 in the trasnmission?

http://www.toolking.com/1/sta_lube_...id_gl_4_multi_purpose_gear_oil_1051783271.php

 

That looks like the stuff!! I just ordered some CRC 140w GL-4 for the steering box and knuckles, didn't see this though....

I see Carquest carries it..if found it through their website using the SL 24239 number...I suppose any auto parts store that carries CRC products would be able to get it...

http://www.carquest.com/webapp/wcs/...es+-+1+gal__10151_-1_10651_1423172_?acesApp=0

Thanks for the post!

 

Every source that I've tried shows this GL-4 to be out of stock, including toolking......though Carquest shows it on the web site the stores do not show it in the computer so they are unable to order it....anyone able to find it

 

That's the same stuff I bought at the local NAPA

 

The last I bought was from NAPA, Sta-Lube, API/GL-4, Part No. SL24239, One gallon container.

 

Try a farm store, implement dealer,ect.