Murphy and the Rear Main Seal

[cattlerepairman]

Murphy and the Rear Main Seal - Murphy messed up

Had replaced the rear main and modified the carrier while I had everything apart. Did "fingernail check" on crank for groove and new seal dis not sit in same spot as old one anyway. Ran fine for over 50 hours now.
Today....highway run for an hour. Pulled into parking lot and used the cool-down period at idle to do a walk around. Piss**ng liquid from bell housing area.
I thought impure thoughts, shut her down and walked away to TSC for some purchases. When I came back the leak had stopped. There was a sizeable puddle (about 8 inches diameter). Started her up and moved forward to inspect liquid....black....thin...not stinky....engine oil.
Checked idling truck...no leak.

Drove home. Noticed clutch will slip in 5th when flooring throttle. Took it easy while swearing some more. Inspect at home...no leak.

Plan is to shoot brake cleaner up into the bell housing and get the clutch clean - ish. Then think about what to do.

Darn.

 

[Jericho]

Been there done that, Use the brake cleaner, if you have the ceramic clutch your in like Flynn, it will dry clean if your douche it enough. Ive found there are two culprits 1. over service of the engine oil, oil will ,"crank case pressure "by the seal on to the disk . Check oil level for correct service BY THE BOOK. If its over ,correct service . 2. leaking rear main seal. When my truck is in winter sleep mode (7 months) I find the seal leaks initially in the spring until ive thoroughly warmed it and driven a 100 miles or so, then is good for summer (8 weeks) if service is correct and you still get oil on the clutch, look at the crank output shaft seal as the culprit. , it would appear you disturbed it already . sooooo !

 

[cattlerepairman]

Opened inspection cover and washed the bell housing out with 5 cans of brake cleaner. 2x4 to keep clutch depressed, engine idling to get the clutch and flywheel as best as I could. Oily mess cleaned up to clear runoff. I also cleaned my hands through the gloves and soaked half of my face, so I will probably die of liver failure with that brake clean stuff....

All the while, no more oil leaking. Not a drop while stopped and not a drop when idling, warm or cold. This leads me to believe that this was the 30 weight engine oil from the transmission. I put 4 quarts in...maybe she did not like that and puked the excess after it got really warm during the 100 km/h (60 mph) sustained highway run (I have the 5th gear OD mod). Looking back, this was the longest and fastest highway run, yet.

My theory is that if it was the rear main, it would keep on making an awful mess as long as there is oil in the crankcase.

So... I am feeling better now! Up yours, Murphy!!!!

 

[dmetalmiki]

I do like those positive vibes...Looks like you solved the problem, but keep a wary eye open.

 

[gimpyrobb]

I bet its gear oil from the trans.

The way the flywheel is made, its hard for motor oil to get to your clutch.

 

[M35A2-AZ]

I bet its gear oil from the trans.

The way the flywheel is made, its hard for motor oil to get to your clutch.

That would be my guess also. I had the same problem and it was the transmission.
When they rebuilt the transmission they plugged the drain back hole with RTV.

 

[cattlerepairman]

Thanks guys! Took her out for a test drive....clutch slippped a little in 5th in the beginning (that LDS has a lot of power!) when accelerating hard, but after a while it seemed to hold just fine.
Maybe I give her another brake clean spray.
No new leaks. I am happy.

 

[gimpyrobb]

If it does happen again, open the trans fill port. See if any fluid comes out.

 

[Jericho]

Failed to mention before, If your doing 60 whats your rpm, If it is near mine your pushing or over redline, Mine leaks if I do that as well, did a run from Bolling AFB DL to Pease AFB NH. had to stop in Jersey to clean clutch disk off. reduced Rpm, problem went away

 

[cattlerepairman]

Failed to mention before, If your doing 60 whats your rpm, If it is near mine your pushing or over redline, Mine leaks if I do that as well, did a run from Bolling AFB DL to Pease AFB NH. had to stop in Jersey to clean clutch disk off. reduced Rpm, problem went away

My rpm at 60 mph are 2400. Engine is governed to 2500, but that is already scary speed in an M35A2.

 

[rustystud]

Opened inspection cover and washed the bell housing out with 5 cans of brake cleaner. 2x4 to keep clutch depressed, engine idling to get the clutch and flywheel as best as I could. Oily mess cleaned up to clear runoff. I also cleaned my hands through the gloves and soaked half of my face, so I will probably die of liver failure with that brake clean stuff....

All the while, no more oil leaking. Not a drop while stopped and not a drop when idling, warm or cold. This leads me to believe that this was the 30 weight engine oil from the transmission. I put 4 quarts in...maybe she did not like that and puked the excess after it got really warm during the 100 km/h (60 mph) sustained highway run (I have the 5th gear OD mod). Looking back, this was the longest and fastest highway run, yet.

My theory is that if it was the rear main, it would keep on making an awful mess as long as there is oil in the crankcase.

So... I am feeling better now! Up yours, Murphy!!!!

You really shouldn't be using 30w oil, especially "modern" engine oil. It has to many other additives that are not good for the transmission. Also, it is too "light" of an oil for the transmission. The gear specialist from "Tremec" said to use 50W gear oil. You can see how "watery" it gets when hot, and since there is no oil seal on the input shaft it just "flows" out. Even if you keep the oil level low the oil that is in there will get "whipped" up from the gears spinning. Believe me that oil is flying around in there ! If you don't believe me then just take your transmission cover off and start-up your truck and with the transmission in neutral let out your clutch. My boss at a rebuild shop once had this great idea on how to check for a sloppy synchro. It didn't work ! All it did was make a mess and get me totally drenched in gear oil !

 

[cattlerepairman]

Rusty, it is about half 40W and half 30W non detergent oil. Waterloo called for 40W but there was only 2 qts available. I used to run 80/90 gear oil in it. 30W sure is thin.

 

[peashooter]

sounds like we need to get that transmission input seal project rolling again from Jeep sinker. I dont know if the vent cap on the transmission can cause issues like the same vent cap will do (if plugged) to the axles and xfer case but you might as well check that also when its accessible. I think its up near the shifter if I remember right.
I'm not sure what the consensus is on the Lucas oil stabilizer, but I've been adding that to my trans, xfer case, & axles. I finally have no leaks after running vent lines instead of those breather caps that often didnt breath.

 

[rustystud]

Rusty, it is about half 40W and half 30W non detergent oil. Waterloo called for 40W but there was only 2 qts available. I used to run 80/90 gear oil in it. 30W sure is thin.

I would go with the recommendation of the engineer from "Tremec" myself which he called for a 50W oil gear oil. This will provide all the lubricity for the roller needle bearings you would ever need.

 

[texas30cal]

Just curious, what is wrong with 80w90?