Engine/Transmission (1994 - 1998) oil leak

[BHigby]

i got a 94 ctd 4x4, 5spd, and it looks like my rear main is leaking. Is this a common problem on these trucks and how difficult of a job is this going to be. The truck has 177k on it.

 

[Andy Redmond]

Transfer case and trans require removal, its some work. You should have or rent a good quality trans. jack, should you attempt this on your back at home.



Try National seal # 39805 $45 +/-. Cummins offers an oversize id seal and a brass wear sleeve is pressed/red locktited on the end of the crank. R&R Priceless!



Maybe have someone add dye to the oil and assure that's where its coming from? Valve cover gaskets, tappet cover etc. can drip down and mimic this prob. It would sure stink to R&R the trans case and trans only to find out it was a less involved process.



Tappet cover R&R isn't much fun as the injection pump is removed. Joe Donnelly has a post about some black RTV to seal a leak w/out injection pump removal. It worked once for a customer (holding 40,000), however, I've pulled several pumps too. . so are you lucky?



Good luck

Andy

 

[BHigby]

i'll clean it up and check it again, but im fairly sure its the rear main. It will give me an excuse to upgrade the clutch anyway. thanks for the help.

 

[bmoeller]

i've had to replace my valve cover gaskets a couple of times.

 

[CATCRACKER]

make sure you vaccum pump gasket on your power steering is not leaking and like b said vavle cover gaskets my bet it that it is not you rear main.

 

[BHigby]

i hope it isnt the rear main. I can see oil coming down between the bell housing and the block. wouldnt the rear main leak into the bell housing? The guy that i just got the truck from recently adjusted the valves, so maybe something didnt seal up right there. I leave a fairly good size oil spot in the driveway every day.

 

[BV]

Just replaced my Step Bros original valve cover gaskets becuase of the oil slick he was leaving. If you do replace them, go for the grey (marine) gaskets and don't forget to replace the little orings on the bolts. Also - Might as well adjust the valves if it's been awhile.



Good luck - Marty

 

[CATCRACKER]

little orings are a problem they wear over time and disapeer. of course i had two go out and it was on #6 and #4. no biggie takes 5 min to change .

 

[RSergeant]

oil leaking also

I was just about to post the same question. after rebuilding my engine and building my twins I havent even been able to drive my truck because of my rear main leaking I did not know of the brass sleave (stemco setup for the rear main) Thanks guys

 

[w-cummins]

I was just about to post the same question. after rebuilding my engine and building my twins I havent even been able to drive my truck because of my rear main leaking I did not know of the brass sleave (stemco setup for the rear main) Thanks guys

I don't know about the brass sleave, but I do know that they make a spedie sleave to repair the crank. I purchased one many years ago and it was $$$$ about $140 if I remember correctally from Cummins NW.



William Cummins... .

 

[BHigby]

for that price it should be made of gold. is it necessary to use a speedy sleeve when replacing the rear main. If the rear main is leaking, would the oil drip down out of the bell housing, or down the back of the block?

 

[crabman]

New SBC Saga

BHigby,

Have you checked the level of oil in the transmission lately? If it is low or have you had to add to it lately, I would first check the front seal on input shaft of transmission.

If it is leaking, it will leak toward front and be picked up by clutch and related gear and thrown outward. Oil will drip down back of pan and out bell housing dust cover. It will look just like the rear main is leaking.



It does entail pulling the transmission but it still is way better than doing the rear main. Besides, if it is leaking it is time for a new clutch!! Seal costs about $3. 00.

And thats how I got a new SBC.

crabman

 

[Tomahawk]

Something else to think about, when I purchased my 97 brand new it had what appeared to be a rear main oil leak. Turned out to be a cam plug oil leak.

 

[KYOUNG]

MY 94 had a "rear main leak" this summer, my transmission shop was getting ready to put 5th gear nut backon for the umpteenth time. We decided to pull transmission to fix rear main and discovered that the input shaft seal was leaking because the pilot bearing had dissintegrated and was whipping the front bearing and seal out.



Lucky the 5th gear came off when it did

 

[w-cummins]

for that price it should be made of gold. is it necessary to use a speedy sleeve when replacing the rear main. If the rear main is leaking, would the oil drip down out of the bell housing, or down the back of the block?

No they are only needed when the seal wears a groove in the crankshaft...



William... .

 

[bmoeller]

The guy that i just got the truck from recently adjusted the valves, so maybe something didnt seal up right there. I leave a fairly good size oil spot in the driveway every day.

That is why the VC gaskets got replaced the second time. Snugged up the bolts. It only slowed it down. Had 3 leaking, but put in the whole set.



It was fine for a couple of days, 'til I went to a truck/tractor pull severall hrs. away. Lost a gallon of oil on the way back. Saw the oil on the ground when I stopped at the CB shop my way home.