Novak Conversions Jeep Wrangler TJ engine mounts

Which gear oils?

TJtaco4

New Member
Original poster
Joined
May 13, 2021
Messages
3
Location
CO
What gear oils is everyone using to replace them?
I'm guessing it's:
-front diff
-transfer case
-manual trans
-rear diff

Not exactly sure what options exist (LSD vs non, etc.) in terms of "Well if you had an '01.7 TJ with the rare ABCD123 tranny 5spd then it takes Canola Oil"
am guessing synthetic 75w90 would work for everything
but I hear the trans is different from most other vehicles in that it calls for something much thinner than 75w90.

I know with German cars it usually goes like this. There's the retard who does what everyone else does, and the smart guy.
The retard, let's call him Beebo, will be like "Hurr durr Motul Gear 300 75w90" - even though that gear oil is garbage in the sense it shifts like shit even in mildly cold temps, possibly causing damage shoving that gear selector hard to try and engage a gear. But Beebo loves it because the bottle looks cool and he thinks he's a go fast racer in his slow old car due to driving to some sort of performance shop to pick up a few bottles of that rare hard to find overpriced $14/qt Trash Oil

And then you'll have the one smart guy who's like, "I noticed problems with the above oil, so I picked a different brand 75w80 that qualifies for the same part number/spec and is compatible, but has better cold shift properties."
(he picked it because it has better cold shift properties)
And then when you go to drive it after copying this smart guy and installing this oil,
you find out it has better cold shift properties.
Which matters, because on a daily commute, it takes at least 5 miles to warm up your engine oil. Even longer your trans gear oil that is thick and not heated by the burning of fuel in a combustion chamber a quick thousands of times.
So most of your shifting, is cold shifting
not "well we're trying to set a record lap time during LeMans so we've pre-heated the fluids and done 10 warm up laps in this here track car"

I am guessing the same will apply to Jeep

I will continue to search this topic for consensus. However, thought it wouldn't hurt to ask what the latest up to date opinion is.

tranmission-gears-e1508953945504.jpg
 
for diffs: 80w90 or 75w140 if you plan on towing, or really any viscosity close, whatever fits your need.
for transfer case: any ATF
For manual tranny: MT90 if you got a 1999 and older and redline MTL or synchromesh If you gotta 2000 and newer
 

I dunno someone asking what gear oil to put

for diffs: 80w90 or 75w140 if you plan on towing, or really any viscosity close, whatever fits your need.
for transfer case: any ATF
For manual tranny: MT90 if you got a 1999 and older and redline MTL or synchromesh If you gotta 2000 and newer

that is wild
ATF in the transfer case
even though most truck transfer cases take 75w90 gear oil

Redline MT90 is garbage. Syncromesh is cheap.
I guess I'm on my own.
 
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I dunno someone asking what gear oil to put



that is wild
ATF in the transfer case
even though most truck transfer cases take 75w90 gear oil

Redline MT90 is garbage. Syncromesh is cheap.
I guess I'm on my own.
Bruh what
MT90 has helped my cold shifts in my AX15, so I recommend it if you gotta AX15 or AX5 but I don't know what you have because you have yet to tell us.

Yes any type ATF will work in the transfer case, keeps it cheap and what the FSM says

"I guess im on my own" There are 500 posts on "what tranny oil should I use" including the link in post #3. There is plenty of reading material on this site about your issue so do with that as you want
 
I dunno someone asking what gear oil to put



that is wild
ATF in the transfer case
even though most truck transfer cases take 75w90 gear oil

Redline MT90 is garbage. Syncromesh is cheap.
I guess I'm on my own.
You should definitely use 75W90 in the transfer case. Thanks for stopping by.
 
  • Haha
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Redline can help, hurt or do nothing.
This very forum has mixed reviews of it. Royal purple is going to give similar results. Some good, some bad, some meh....
In other words they're not something magical.

If your Manual Tranny fluid is way overdue for changing any fresh Syncromesh fluid will be of help. Keep that in mind.

75w-140 full synthetic for your diffs.

ATF4 for your transfer case

Go wheeling!!
 
Novak Conversions Jeep Wrangler TJ engine mounts