Royal Purple - Trans lube ?

My '73 has a whine in 1st gear and also makes a bit of noise in 2nd. I will be working on the thermostat tomorrow and figured that I would also drain, flush and refill the trans with some new lube. Has anyone ever used the "Royal Purple" 85-140 synthetic lubricant? I thought that perhaps a "slicker" type of oil might quiet things down a bit. Anyone have opinions on this?
Thanks again -

The only problem I have heard is that they do not shift as well since the sychros need friction to spin up.

Try Redline MT-## series especially for manual transmissions (and those pesky syncros). I think I have MT-40 in my VW van but that was specifically to meet the VW spec.
Royal Purple may have additives for syncros...

Remember guys.....NO GEAR LUBE IN THE GEARBOX if it's a Spridget box..............engine oil only. 20/50 is recommended for your region of the country Ramon, and any good quality lube will do a good job.
You could use a straight weight too if you choose, say 40W or 50W. I used to use Esso Aviation 100 in my truck transmissions which is a straight 50W mineral oil. Not even sure if it's still available, but if it will cool an 18 speed truck tranny, it should be able to handle a lil' ole ribcase.
In my ribcase I was using Castrol 20/50. Always been a great oil. The Datsun box calls for gear lube, so I'm using Castrol. I don't remember the weight, I think it's 75/90, same as in the diff .

I use Red Line gear lube in the differential. Seems quieter. I was told it's a Jag owner's trick.
Royal Purple in the Scion motor since after a 2500 mile break in. I just rolled over 100,000 miles, but it IS a Toyota.

I tried some Lucas transmission fix as an additive to my 20/50 oil. I couldn't tell a difference but the stuff is so thick it was a pain to get into the fill so I'm not sure I got as much in as I could. This stuff has received some pretty good review and my box is a bit grumpy but I can't tell much difference. It does seem better cold, maybe I should put something heavier in there.....

I added the 85-90 Royal Purple trans lube yesterday (& installled the missing thermostat). I have not had it in the road yet, but did try it a bit here at home. It seemed to be OK. I will get an idea tomorrow on the way to work & post back results. The old lube that I drained was a bit "milky" (due to water?) so I figure that it needed changed anyway. If it works OK I may go ahead flush the differential & replace with new.

I was told from a MG guru to use non-detergent 30W in the gearbox. :S

Ramon, good luck with the heavy lube. As Andrew said, the box should only have 20-50 engine oil in it. The whine in first is normal, that's a straight cut gear which will make noise, the others are helical cut gears and should be much quieter. A note about synthetics, a fellow Spridget owner with a 1500 tried a synthetic lube in his transmission as well as trying ATF and both worked great as far as noise and shifting went, but the seals leaked like they weren't there. Not nearly as bad when he went back to straight engine oil, seals much better.

What about reverse? Midge is whinny in both 1st and reverse. She's great in 2-3-4.

First and reverse both use straight cut gears and have a normal whine.

OK, what i ended up using was something call "Royal Purple 75/90 Max Lube High Performance Gear Lube". I drove about 20 miles to & from work this morning and I LIKE IT!
Basically, it shifts much smoother, and has less "whine" in 1st gear. Overall, I would say that it worked good for me, and I am happy with the change. FWIW, I bought a quart and used it all plus about 4 or 5 ounces more to refill after flushing.

Ramon, keep us posted how this lube works after the temp changes somewhat. Like on a 60+ temp day if we get one soon which would be nice. Sounds good though so farsince it worked early today in cold temps.

slowride

I sell and use Amsoil products.
Your gearbox should have 30W non-detergent or a 20W-50.

But the milky substance was the water and most likely has destroyed the bearings............

No matter how good a lubricant, it cannot replace metal.

I use Amsoil 5W-30 synchromesh in my '77 'B'

http://www.amsoil.com/storefront/mtf.aspx

The shifting is butter smooth, and quiet.

Ramon,
I want to re-state that the recommended lubricant for these gearboxes is ENGINE OIL in either mono or multigrade. Gear oils may result in damage to the gearbox. Typically synchro rings. The short term improvements you see may be overshadowed by an expensive teardown later on. Some gear oils actively attack brass and bronze components in gearboxes, which is why they are not recommended. Spridget gearboxes have brass synchro rings I believe. FWIW

Read, what Bill said here, it explains it all, very well too I might add as most of his advice normally does, sometime you guys crack me up :)


Race car transmissions use stright cut gears, because they are stronger, the drawback to them is they whine, on some race cars like a Formula Ford, the decible limit (the noise amount) coming from the straight cut gears in the transmission out weight that of the engine. The MG Spridget gearboxes as Bill already stated have straight cut first and reverse gear (if you ever took off the side cover and simply looked, you'd already know this), so you can put maple syrup in there if you want it's still a straight cut gear and will whine. If you talk to transmission experts like John Espitido who do this for a living and actually do conduct bench test, you'll see they they under testing using several type of oil, have proved that SAE30, and 20/50 out performs all others in these gearboxes in both lubrication and heat, I fiquire John had forgotten more about theses gearboxes than the rest of us will ever know, so why not listen to him, over the guy at the parts store counter.

Thanks for the info on this Hap. I'm running Castrol 20/50 in my box and am glad now that I know the reason for the spec recommendation.

BTW.. You have a very nice GT in your profile. Vera nice indeed.

I don't want to veer off course, but it may be worth mentioning that from 1975-on the spec is for gear oil in the tranny. Just thought it may be worth mentioning for those who are uncertain. ....would like to be corrected if I'm wrong.

Worth noting Brian.............RB cars have the Triumph box, different animal all together