How do you feel about LHT's recommendation for Royal Purple SyncroMax in the gearbox?

-- Chuck

Yea, I have the same question. He certainly seems to thing is it the bomb. Others here use it?

I'll admit part of the question was "loaded" since LHT's recommendation for the differential was "good enough for me" but apparently their gearbox recommendation isn't quite up to that standard. :) (Can take Billman's recommendations to the bank, of course.)

I'm running the Royal Purple SyncroMax in my gearbox since last week. Seems fine. Be aware the stylish shape of their bottle did not let my little hand pump inlet reach the bottom. Combined the residuals from both bottles into one and it was deep enough to fill the gearbox. I never know what to do with the few ounces left over from two quarts of gearbox oil.

My Royal Purple engine oil analysis has been flawless the last 4 years (and 3 samples) other than a high, but not alarming silicon level this last time. Cleaned the air filter and will see what the next sample looks like -- I may pull one in a month or two. Sample was drawn thru the dipstick not the sump.

-- Chuck

Castrol Syntrax Longlife 75w-90. Fully synthetic, recomended for BMW cars and MAN trucks, cant be bad....

https://www.castrol.com/de_de/german...fe-75w-90.html

He (LHT) was joking/commented in one of his vids, that he doesn't use Amsoil because he doesn't want to deal with some guy in a straw-hat, on the side of a highway, in an old minivan/truck, slanging Amsoil... in other words, it is harder to get than just running to the local auto-parts store and buying Royal Purple.

I think LHT just uses whatever is easiest to obtain at the local auto-parts store.


As for my diff... I use Mobil1 75w-140. Dunno if it's any better or worse than the 90 weight version though. I just read it's more heavy-duty. Idk, Hmmm..
For tranny.. I have Honda MTF in it now. It's soon due for a change... I will try Amsoil.

When I first bought my car, I replaced all the fluids... and, the gearbox became noticeably notchy'er after the fresh Honda MTF change.. So, I'm assuming the previous owner might've had something else better in it before I changed fluids. Maybe GM/ACDelco (since that's popular with ricers and Honda peeps) or maybe even Amsoil. Irdk.

I run M1 75/140 in the rear end and I tried different lubes in the tranny and found the Honda stuff was just to thinn in the summer. Another S owner told me to try Red Line so I tried R/L MTL, still to thin on our long summer drives. Emailed R/L and they said I could use the MTL, MT-85 or MT-90 or mix any of them to get what I wanted. I change my tranny fluid twice a year(fall, spring) and found the MT-85 works good in the fall, winter and a 50/50 mix of MT85 and MT90 for the spring, summer.

I guess I'm getting lazy in my old age because I have 4 sprayers(1 two gal. 3 two qt.) that I modified to use to fill the rear ends on my S, truck, motorhome and the transmission's in my truck and S. Each sprayer gets it own oil, I never mix the motor oil with the gear lube thats why I have 4 sprayers. Makes changing fluids so easy and fast. The motorhome(class A) is the worst to have to put oil into, that two gal. sprayer works great just put 7 qt. of oil in the sprayer and pump till its MT.

ROD

Here you go, don't know what year but you get the idea
https://www.quadratec.com/categories...=diff%20covers

ROD