Synthetic Gear Lube (for diffs and tranny)

[JeepinMaxx]

I was thinking of using Royal Purple synth in my AX15 and D30/35 diffs. Anyone have experience with this? (where can I get it local?) Also what fluid works best with the NVP231 transfer case? I know it uses ATF - but what works best? Thanks for the input...

 

[toyworx]

Redline. Only way to go.

 

[xjmark]

I think Driving Image in Farmington has Royal Purple in stock.
Ask for Bill. 1-860-675-4211

 

[NomadJeep]

Best stuff I ever used was REDLINE.... changed my YJ tranny fluid up in NH when I lived there to try and get rid of a hard shift when cold, as well as a second gear grind when nipply outside... Used Mobil I think,,, did nothing... then I tried Redline and the 2nd gear grind was completely GONE.... Made me a believer...

I have been buying it ever since (Diff, tranny, and T-case) No leaks or anything, unlike the Mobil 1 that keep driving me nuts leaking out the RMS... (Rubi and YJ)

Advance now carries some of Redline ($$$$), but you can also get most of it at Cofields in Glastonbury...

However the cheapest place was some place on line in MD, and they were like 5 bucks cheaper per bottle including shipping... have to try and find it...


Synthetic Hells yeah.....

 

[Zaedock]

It's just about time to go through the fluids in the YJ and I was thinking about synthetic for the SM420 tranny and the diffs. I actually read that running synthetic will give you better mileage due to less friction. On the Farm trip we did a few weeks ago, I averaged a little over 18mpg in my YJ (a 2.5L) and think I can shoot for 20mpg. I think I would drive her more to the trail head instead of trailer (besides, it's more fun to drive).

I was looking at 75W90 synthetic for my SM420. It's out of a 1965 Chevy dump truck. What do you guys think about the 75W140 for better hot weather protection? Do you think it's too thick? I currently run standard 80W90 gear oil in the tranny and diffs (rebuilt Dana35 and Dana30).

A little story...
A couple of years ago, I snapped both rear axleshafts and used 85W140 'cause that's all I had at the time. I pulled the diff cover when it was 15deg f outside and the gear oil didn't move. It was like jello.
It was pretty cool.

 

[cwlongshot]

I just tried this stuff! I can't say I've seen any difference though.
I dont expect to notice it untill the cold weather sets in. My tranny was hard to shift on those really cold mornings last year.

So far I have only installed it in the tranny and Xcase. I just reinstalled my rear locker a couple months back and filled it with reg syn Mobil 1. So thats OK for a while, or my next deep water xing! But I have to swap out my front locker next week and I'll refill it with the royal Purple.

I hear you on the Jello oil in the winter!!!! I am a firm believer in what synthetics can do for your lubrication needs!!!! I've run Mobil1 in my motors for years, great stuff!!!
CW

 

[JeepinMaxx]

What grade did you put in? I just realized that they sold me Red-Line 70W80 API Grade GL-4. The Chilton's manual shows 75W90 GL-5. I already filled my D35. Will this lower grade hurt anything? I plan on using it in my tranny as well. I paid $10/qt so I hope I can use it. I appreciate your feedback.

 

[cjshloman]

Im gonna have to go to cofields and check oout prices on this red line...hmmmm. I just swapped my motor oil to amsoil and now wanna go syn in my diffs. Ill let you guys know some prices since I live in glastonbury. Bull.

 

[jon]

GL-5 stuff can eat the synchors in the ax-15s. not sure about mobil 1 and redline stuff. But I put synchromesh in my tranny and it made a huge difference. and you can get it at "zona de auto" or autozone every where except by me.

 

[cwlongshot]

I just went out to the garage and grabbed a quart. I've never herd of an oil "eating" syncros before. Maybe so but its the first I've herd such a thing.

This bottle of 75W90 Max-Gear says:

"Meets the performance requirements of API GL-4 and GL-5"

"Contains limited slip additive"

"Perfect for lowerunits of marine outboard/outdrive units, noncorrosive and excellent water and seperation characteristics"

"Great for manual transmitions requiring GL-4 orGL-5 fluids"

"Meets performance requirements of MIL-L-2105E"

CW

 

[JeepinMaxx]

So is the GL-4 70W80 OK for my AX15 tranny? It's spec'ed for GL-5 75W95. I plan on changing the fluid this week - I'd hate to to waste a bunch of $$ on Red-line if it kills my tranny...

 

[jon]

some of the additvies eat away at the brass synchros. take an ax-15 run on normal gl-5 apart and check out the pitting on the synchros.

I'm too lazy to search around but its definately been mentioned, on place like JU and pirate. I know there are a few threads over on neow.

 

[Zaedock]

Well,
I took the plunge yesterday and bought Mobile 1 Full Synthetic 75W90 gear oil for my SM420 tranny. I wish they sold the stuff in gallons. My tranny takes A LOT of oil. I picked it up from Advance Auto. They also had Valvoline synthetic blend which was my second choice, but I figured I'd try the full synthetic and see how it works.
I've never heard of gear oil "eating" away brass synchro's before. This is something I will do some research on. It may be true on the AX5 or AX15 Japanese tranny's. I know that certain Japanese components take special fluids. It could also be possible that those particular trannies had a bad run and were built using "sub-par" synchros. Remember, most vehicles are assembled with parts supplied by the lowest bidder.
All the more reason to swap in American iron with a granny-low.

 

[Zaedock]

HOLD ON!!!!!

DON'T BUY MOBILE 1 FOR YOUR TRANNY.

In my investigation, I checked out the Mobile1 web site and I called their 800 number. The rep said that the full synthetic 75w90 gear oil WILL eat synchros. It is intended for differentials and T-cases. I also probed the website and cannot find ANY info that states the oil can be used in a manual tranny.

Looks like I'm heading back to the store...

 

[jon]

synchromesh.... its formulated for synchroed trannies.

 

[Zaedock]

Who makes "synchromesh" or IS that the name?

Is it synthetic? I wonder if it even makes a difference in my 1965 transmission, when all they used to have was 80 weight...

 

[markdupont]

the reality is... almost every time you go wheeling, you encounter water... and enevitably, water enters your diff... and regardless of how well you take care to seal your diff, water enters the diff... and then there's condensation, especially in the winter when the housing is cold and the gears get hot... that said, synth is too expensive for the frequency of my gear oil changes, I go with the best el-cheapo from wallyworld. I save the expensive juice for the motor and x-fer case.

Mark

 

[jon]

penzoil makes it.

its called synchromesh.

it comes in a yellow gear oil bottle.

probably won't make a difference. its an sm420 though so anything to help in shifting that beast would be great.

 

[jon]

maybe sold under quaker state as well or instead of penzoil

 

[cjshloman]

So that syncromesh stuff will work in my 98 tj? Im gonna have to get some. Help with hard shifting during cold by any chance? Bull.