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Tran and Differential Oil?

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mountainman

mountainman

Jedi Trainee
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What should I use a far as tran & differential oil in my TR3? I have read different grades and wights. I am geting ready to refit them both.
Thanks
Greg
 
GL4 gear lube. I bought mine by the gallon at a NAPA auto parts store. It has no additives that would eat up the brass/bronze in the tranny. Do an advance search on TR3 fluids here in the forum and you will get all the info you could ask for, as to the whys and wherefors on using ceertain oils and lubes for our older cars.

Good Luck, Tinkerman
 
Redline has a lube supposedly designed for older manual transmissions. I ordered their MTL 90wt. Brad Penn Racing has motor oil with the ZDDP additive needed. There was a distributor close by so easily attainable for me.

Just for your consideration.
 
I've used Valvoline 20W50 Racing (engine) oil in my TR3A gearbox for over 100,000 miles with good results. Ditto Valvoline full synthetic gear oil in the diff.

BTW, conventional GL4 gear oil usually still contains the additive that damages copper alloys; it just contains less of it than some conventional GL5 oils do. It's that additive that gives used gear oil that distinctive smell.

IMO, it's not whether it's GL4 or GL5 that is important, but whether it meets MT1. MT1 should be safe for the yellow metal found in TR gearboxes and diffs.
 
It's my understanding that the additive that eats the "yellow" metal, is sulfur. The additional sulfur is what makes it possible to meet the GL5 specs. I think this is right, as my memory is not what it used to be. Anyhow, I think you can still purchase Pennzoil GL 4, but, you may have to go to the distributor, and you will have to buy the whole case, 12 quarts. I also question how many years it would take to do any damage, no one has answered this question to the best of my knowledge.
 
NAPA still has GL-4 Sta-Lube Gear Oil in gallon containers.
 
TheSearcherMan said:
It's my understanding that the additive that eats the "yellow" metal, is sulfur.
Click to expand...
Well, more accurately, it's a compound that contains sulfur.<div class="ubbcode-block"><div class="ubbcode-header">Quote:] The additional sulfur is what makes it possible to meet the GL5 specs.[/QUOTE]True, but there are other additives that perform the same function without containing sulfur. Plus synthetic oil, with it's higher base film strength, needs less additive help anyway (to meet GL4/5).<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I also question how many years it would take to do any damage, no one has answered this question to the best of my knowledge. [/QUOTE]I believe that's because the time required is highly variable. The additive does not do the damage directly; instead when the additive is called into play (by extreme pressure and heat) it breaks down into other compounds, including an acid. It's the acid byproduct that does the damage. So, how quickly the damage occurs depends on how hard (and how often, etc.) you drive your Triumph.

I was dubious myself, but I recently rebuilt a Triumph diff that appeared to have had conventional GL5 run in it. The "old gear oil" smell was very strong, the brass washers were badly worn, and the blackened material (not sure offhand what compound it is) was very much in evidence.

And since loosey-goosey differentials (indicative of worn brass washers) seem to be quite common in Triumphs, perhaps the problem is more prevalent than we realize.

But just to reiterate, as I see it, the big problem is that "GL-4" does not guarantee the oil is safe for yellow metal, any more than "GL-5" guarantees it is not safe. Both specs have tests for "yellow metal" corrosion, but the GL-5 test is actually MORE stringent than the GL-4 test! In fact, most GL-5 oils will pass all the GL-4 tests (and there used to be "combination" oils marketed).

So, MT-1 is the spec to look for, to be sure the gear oil you are buying is compatible with "yellow metal"; plus a GL-4 or GL-5 rating to be sure it protects the gears in the diff.
 
Like Randall, I've used Valvoline 20W50 motor oil in the gearbox and overdrive of my 1958 TR3a for 18 yers (100,000 miles) and I've used GL4 EP oil in my differential.
 
GL4 is as rare as hen's teeth around here. I remember someone telling me that a VW dealer was the place to go. I tried my local VW dealers, and they all said that they quit using GL4 about 10 years ago. Now all they use is synthetic. My local NAPA carries Valvoline synthetic, or I can go into town and purchase Redline MTL. What would be your guy's choice?
 
For a diff, I'd go with the Valvoline (actually, I do
grin.gif
). Probably fine in a gearbox too, but I've heard that it can be too slick for good synchro operation. Which may not be true (especially since Valvoline specifically says otherwise), but that's why I haven't tried it.

Now that I've undone my poorly thought-out modification, the J-type in the Stag is working quite well with the MT-90. Smooth and sure, every time.
 
The link that recordsj gave is a good one; the first one that I have seen that actually gives a good comparison of GL4 and GL5.

One point though, the API service designation of GL5 includes protection against copper corrosion. I would recommend using GL5 oil, but if you want to use GL4 make sure that it states on the bottle that it is compatible with yellow metals.

One other point, when the components in the oil break down, the only way that they will form an acid is if there is also water present in the tranny or the diff. If you are worried about acid corrosion, then just change the oil every couple of years.
 
Ya know, if I can find GL-4 at a NAPA dealer here in the boonies, You certainly should be able to find it in the Atlanta area. You have to buy it by the gallon, anyhow I would let my fingers do the walking, call around and see what you can find.

Good Luck, Tinkerman
 
TR4 said:
Redline has a lube supposedly designed for older manual transmissions. I ordered their MTL 90wt.
Click to expand...

When I replaced the tranny lube in my TR6 I went with Red Line MT-90 and am very happy with it. I thought my tranny was smooth before but I can not believe how smooth it is now. The MT-90 is not cheap, seems like it was around $17/qt but now I would not use anything else.
 
tomshobby said:
The MT-90 is not cheap, seems like it was around $17/qt
Click to expand...
Poke around on eBay a little; I've found it for less than half that price ($15 for two quarts, with local pickup).
 
A friend who has and races a BRG Spitfire buys GL4 in 5 gallon pails (or is it 20 gallon pails ?) from Shell. He then re-bottles it in 4 quart poly jugs and I buy it from him at $20.00 for 4 quarts.
 
Great! Now all we need is a marking on the bottle that indicates whether it is a "modern" oil or old dinosaur juice. The old formulas are cheaper ...
 
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