TheSamba.com :: View topic - GL 4 or GL 5

Fri Jul 01, 2016 12:33 am

Wildthings wrote: It is rather pointless to say you "switch to GL-5" unless you specify which oil you switched to as many GL-5 oils give considerably worse shifting. You should also say what oil you switched from.

Just as pointless as you saying "many GL-5 oils give considerably worse shifting." without stating exactly which brands of oil you think are inferior.

I recently started driving a car I've owned for many years but was stored the whole time. The gearbox has very low mileage on it, and even less on the GL-4 the PO put in it. The shifting was so bad I contemplated having to do a rebuild on the trans. The force to get it into each gear was quite high, and 1st gear synchro was completely ineffective.
I decided to change out the low mileage GL-4. I gathered up all the mixed brand oil I had and put it in. 1 qt of Pennzoil 80W-90, half a qt of Castrol 80W-90, and 1 qt of Royal Purple 75W-90. All GL-5 of course.
On the very first shift into 2nd I could immediately tell it was much better. Overall, I would say it now takes about 1/3 of the effort to shift. The synchros work so much better, including the suspected bad 1st gear synchro.
So much for your claim of GL-5 shifting bad and GL-4 being good.

Fri Jul 01, 2016 3:50 am

Sandbar Norm wrote: This looks like it would work well for me.
https://www.amsoil.com/shop/by-product/transmissio...be-75w-90/
or this
http://www.redlineoil.com/product.aspx?pid=46
Norm

Did you bother to read the note half way down the page on your second link?

"MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears"

Fri Jul 01, 2016 6:06 am

Wildthings wrote: Sandbar Norm wrote: This looks like it would work well for me.
https://www.amsoil.com/shop/by-product/transmissio...be-75w-90/
or this
http://www.redlineoil.com/product.aspx?pid=46
Norm

Did you bother to read the note half way down the page on your second link?

"MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears"

Well that makes it easy to choose.

Mon Sep 12, 2016 9:34 am

Have only run this since rebuilding the trans years ago. No problems.

http://www.amsoil.com/shop/by-product/gear-lube/synthetic-80w-90-gear-lube/?code=AGLQT-EA

Thu Oct 06, 2016 8:45 am

Been using this for 4 years on a new transmission with no issues:

Thu Oct 06, 2016 6:18 pm

yeah, it works, but it works better with the right oil.
It says right on the front, it's intended for if you have a limited slip syncros. :P

Thu Oct 06, 2016 8:20 pm

Valvoline™ High Performance Gear Oil is a high quality lubricant to keep your vehicle running in great condition and avoid loss of corrosion protection.

Additional product benefits include:

-Outstanding thermal stability for cleanliness and longer service life
-Reduced chattering in limited-slip differentials
-Gear teeth wear protection from pitting and scouring
-All hypoid differentials (conventional and limited slip) and manual transmissions in passenger cars, light trucks, sport utility vehicles, vans and heavy-duty trucks where an API-GL5 or MT-1 fluid is specified.

Sat Oct 08, 2016 8:12 pm

neil68 wrote: Valvoline™ High Performance Gear Oil is a high quality lubricant to keep your vehicle running in great condition and avoid loss of corrosion protection.

Additional product benefits include:

-Outstanding thermal stability for cleanliness and longer service life
-Reduced chattering in limited-slip differentials
-Gear teeth wear protection from pitting and scouring
-All hypoid differentials (conventional and limited slip) and manual transmissions in passenger cars, light trucks, sport utility vehicles, vans and heavy-duty trucks where an API-GL5 or MT-1 fluid is specified.

Neil....what do you use in your transaxle? About to fill my new Rancho box and shove it in the 68 tomorrow. What do you recommend? My 68 will be street/strip.....built 2276. Built Rancho transaxle.

Sat Oct 08, 2016 10:10 pm

I use 75W90 GL5 synthetic, but you might be able to use 80W90 in your location (I've been through there many times :wink: ).

I use whatever my FLAPS has on the shelf: Motomaster currently, but Valvoline before that, and Castrol. I like the improved shifting with synthetic and GL5 protection at the race track, but also because of our fluctuating weather up here:

Sun Oct 09, 2016 7:29 am

neil68 wrote: I use 75W90 GL5 synthetic, but you might be able to use 80W90 in your location (I've been through there many times :wink: ).

I use whatever my FLAPS has on the shelf: Motomaster currently, but Valvoline before that, and Castrol. I like the improved shifting with synthetic and GL5 protection at the race track, but also because of our fluctuating weather up here:

Thanks

Tue Oct 11, 2016 3:35 pm

modok wrote: yeah, it works, but it works better with the right oil.
It says right on the front, it's intended for if you have a limited slip syncros. :P

As mentioned by neil68, it supports both conventional and limited slip differentials.

Tue Oct 11, 2016 5:12 pm

Right. Valvoline instructions say:
-can be used anywhere gl-5 or mt1 is specified.
-Where GL4 is specified, use valvoline syncromesh mtf
-application is old volkswagen? get bent (no, jk, I made that one up)

says here http://content.valvoline.com/pdf/vps_manual_transmission_fluid.pdf
and here http://www.carquestprofessionals.com/catalogs/chem...6.6.13.pdf
and here http://www.luisa.com.gt/sites/default/files/synpower_gear.pdf

Tue Dec 20, 2016 8:48 am

54 pages of "No GL-4, Yes GL-4, No GL-5, Yes GL-5" and still going strong. :roll:

Wed Dec 21, 2016 11:53 am

Better not go anywhere near the oil thread then :wink:

Mon Jan 02, 2017 5:38 pm

Hello this is Busfixer. I have 40 yrs experience working on bugs and buses, all my own or family owned. When I rebuilt my son's 1978 Camper equipped with factory 091 4 speed, I simply drained and replaced the GL4 fluid with modern Mobil 1 GL5 synthetic gear oil. The original transmission was not rebuilt because it worked perfectly. Sounds logical, doesn't it?

Empirical data many times trumps laboratory data due to unknown factors. For some unknown reason, my son's 1978 091 started whining in 2nd and 3rd gear with the GL5 fluid in it after 5 years. I told him to drain the fluid and he found brass shavings and particles in the fluid. Had him fill it with Royal Purple GL5 but too late.

The 091 is now rebuilt by a well known shop and the main shaft was replaced. However, the empirical evidence of brass/bronze shavings remains and I can't help thinking the GL5 contributed greatly to this.

We will use Amzoil 75W-90 GL4 in the new transmission which I have no doubt will preserve all gears and synchronizers with the stock engine. If you have a stock or warmed over engine, use GL4. If you have a hot rod VW, use GL5 or the best you can get and forget about synchronizer life - save the gears with extreme pressure lubricant. Take it or leave it - Busfixer

Mon Jan 02, 2017 5:57 pm

I had one getting a lot of silver in it. But don't think it had anything to do with the fluid, I think it's probably because the gear adjustments or ring & pinion setups are not set properly.

Tue Jan 10, 2017 5:22 pm

In the Jeep community where the yellow metal synchros were a concern many of us swapped to 15/40 rotella motor oil with completely satisfactory results

And in fact it became recommended by mopar as I recall

Tue Feb 28, 2017 7:38 pm

Holy guacamole, what a thread.

54 pages over almost 9 years, and it took until about page 53 to get close to what many of us who own stock, older VWs might want to know – what to use in our 40 (or 36) hp monsters.

So many of you have written anecdotes that say 'I used GL5 this or GL4 that,' but there is little in the way of brands or any other info mentioned for others to narrow down what's good and what's bad, as we now all know that not all GL4s and 5s are all good and/or bad (did I cover all the bases?).

And when a product is mentioned, sometimes I have read how good something is (i.e. - Redline), and then someone else comes along and tears it a new anal aperture (i.e. - separation of additives from base).

So what I have been able to garnish (thus far) is that I want something as close in formulation as possible to what Volkswagen put in my Type 1 transaxle. I'm not worried about 40 rip-roaring hp and non-hypoid gears tearing up my R&P. I will assume what I want is a GL4 which will, coincidentally, not cause me worry about corroding or peeling yellow metal parts.

I want my smooth shifting to stay smooth. What brand and designation/other info/'model' of gear oil is closest to the VW stuff and/or will fulfill my wants and needs?

Thanks.

Tue Feb 28, 2017 9:31 pm

Napa sells "stay lube" brand gl4, it's the only gl4 on the shelf of any place in town.
I don't expect that it would be great, but it's probably more than adequate to work in place of what VW put in there.

I think if you wanted a particular brand of gl4 oil you could do it, but it might be special order, or from overseas. I like valvoline, so, http://valvolinebulgaria.bg/dev/en/products/transm...75w-90.php

Why is it only sold in europe? Conspiracy?

Wed Mar 01, 2017 4:08 am

The GL-5 myth that it eats yellow metals was a problem from 20 years ago that just has not gone away. Notice how in these 54 pages there are no pictures of parts that are eaten up.

I have run GL5 Valvoline Durablend gear oil for 20 years and have never had the internal parts eaten up by chemicals.