D300 shaft seal

[Dan86CJ7]

id check the valve cover for a leak

 

[EVERYUSERNAMEISTAKEN]

id check the valve cover for a leak

I'll check again. I've looked and couldn't find any fresh oil. I'm going to try and clean around the engine today and see if I can find something.

 

[slomo]

If you run a T-4 /T-5 tranny, you had best run syn 75W-90 gear oil.
LG

You might check that advice sir. 75w-90 or 80w-90 in a GL5 flavor is a no-no. Reason is GL5 has phosphorus and sulfur (exteme pressure agents) that eat brass synchros inside the Transmission . YES the T-4 has brass synchros.

For a T-4 for sure, you need synchromesh fluid. T-5 runs ATF last I heard.

Any Transmission that has brass synchros, never run 80w-90 rear diff type lube. Don't care how synthetic it is or claims to be. That relates to the base oil, not the additive pack.

slomo

 

[EVERYUSERNAMEISTAKEN]

You might check that advice sir. 75w-90 or 80w-90 in a GL5 flavor is a no-no. Reason is GL5 has phosphorus and sulfur (exteme pressure agents) that eat brass synchros inside the Transmission . YES the T-4 has brass synchros.



For a T-4 for sure, you need synchromesh fluid. T-5 runs ATF last I heard.



Any Transmission that has brass synchros, never run 80w-90 rear diff type lube. Don't care how synthetic it is or claims to be. That relates to the base oil, not the additive pack.



slomo

I had read that GL5 is a no-no. However, it’s difficult to find gear oil without it these days. Unless you order it..

 

[Lumpy Grits]

You might check that advice sir. 75w-90 or 80w-90 in a GL5 flavor is a no-no. Reason is GL5 has phosphorus and sulfur (exteme pressure agents) that eat brass synchros inside the Transmission . YES the T-4 has brass synchros.

For a T-4 for sure, you need synchromesh fluid. T-5 runs ATF last I heard.

Any Transmission that has brass synchros, never run 80w-90 rear diff type lube. Don't care how synthetic it is or claims to be. That relates to the base oil, not the additive pack.

slomo

Sir-I stand behind what I said......
The T-4 /T-5 is the same box, with the T-5 having a Overdrive added to the tail section. Most folks know this.
AMC learned about ATF, when the tranny's started burn'n up and Borg-Warner told AMC they are on their own for claims, because ATF was not approved by BW. That is why AMC came out with the 'stink-oil'.
I have run syn 75W-90 since it came out-No issues.
BTW-That syncro deal has to do with the alloy of the brass.
Modern manuals use a different alloy these dayz.
LG

 

[Belizean]

So LG what brand you pouring in ? The more I read the harder it is to get a straight answer

 

[Lumpy Grits]

Valvoline syn 75W-90 has been in for the last 3-4 yrs now. Only have about 4-5K miles on it.

LG

 

[Belizean]

What have you been running for all those other years?

 

[Lumpy Grits]

I have run the syn for at least 10+ years now.
Until I switched to the syn. I use the last of my AMC 'stink-oil'.
LG

 

[slomo]

Pennzoil manual Transmission fluid "synchromesh" is safe for brass synchros. Guys running 75 or 80w-90 beware. Bet your synchros are gone or ate up.

My T-4 shifts with one finger. Sucker leaks like a sieve but shifts great. My CJ has the original box with over 180,000 miles, never been rebuilt. Needs new seals bad though. My T-4 leaks into the Dana 300 and other areas.

The stink oil was AMC 8983-00000 something or other. Several fluids over the years came and gone. Now the recommended fluid is synchromesh.

Agreed, the T-4 and 5 is the same box. AMC used to recommend ATF. Would use synchromesh now.

slomo

 

[Lumpy Grits]

ALL synthetic gear oils are safe for the syncros. That was one of the criteria in the formulation.
The T-4 can not fill the 300 by the design of the adapter between the tranny and t'case and it has a drain built into the adapter to prevent this.
Have you ck'd the tranny vent to be sure it isn't blocked?
My '85 came new with the 'stink-oil' in it.
DON'T LAUGH--Try a bottle of Lucas power steering stop leak in your T-4 .
Bet the leak stops in about 300-350 miles.
LG

 

[Belizean]

Mine works like the day I drove away from the dealership with over 236,500 miles, along with the original clutch also. Hate to go to synchromesh, probably a month later I would be saying it had gone to hell

 

[Lumpy Grits]

Mine works like the day I drove away from the dealership with over 236,500 miles, along with the original clutch also. Hate to go to synchromesh, probably a month later I would be saying it had gone to hell

336K miles on a clutch
Was it ever shifted?
LG

 

[Belizean]

336K miles on a clutch
Was it ever shifted?
LG

236K. Don't want to take that much credit. What can I say. 84 was a good year!

 

[Lumpy Grits]

236K. Don't want to take that much credit. What can I say. 84 was a good year!

Must have been towed a lot.

I'm on my 3rd. in 32+yrs.
First went TU under warranty(diaphragm spring broke)then about 15 yrs back the replacement did the same(Borg & Beck). Went with Centerforce2 and (knock on wood)no issues since.
LG

 

[Belizean]

Towed 3 times with a tow strap behind another jeep for a total of maybe 20 miles. Once electrical once out of gas and once towed another jeep. Told you 84 was a good year. I guess maybe things started going downhill in 85. ️

 

[Lumpy Grits]

That little 4 popper of yours can't hurt anydangthing to begin with.

LG

 

[Belizean]

They worked around the world pretty well for the greatest generation !

 

[Lumpy Grits]

Slo-is safer for us old-farts.


LG

 

[Belizean]

Mine does 65-70 down the road. Don't think with a V8 I would want to go any faster than that in a shot wheel base.