I am in the middle of installing a new transmission on my 89 E-150 and thought i would take the opportunity to fix a very small oil leak at the rear main seal. The 351W is a 1984 motor built in April of 84 so it has the two piece rear main seal. I would replace the rear main seal except I can't remove the oil pan right now since the engine is being supported by a jack under the oil pan while the transmission is out.

I purchased a "Speedi Sleeve" type product (mine is a Timken crankshaft resurfacing sleeve, but it is the same idea as the "Speedi Sleeve") hoping to be able to remove the flywheel and press the sleeve over the end of the crankshaft and into the existing seal surface. My plan was to avoid pulling the oil pan and old seal altogether and just slide the sleeve in place and restore the sealing surface. I researched the installation a bit more after ordering the part and it appears that I have to remove the old seal to install the sleeve.

Here is my problem: I have to remove the flywheel to install the sleeve, but I can't support the engine in the van while the transmission is out without something under the oil pan to hold the motor up. But with the oil pan in place I can't pull the rear main seal since it is the older two piece seal.

Am I hosed? Can I install the sleeve backwards and gently slide it into the existing seal and trim the extra installation flange off the back of the sleeve?

Help. Thanks.

 

I'd say hosed.

Backwards? It will probably leak like a firehose.

Live with the small leak. Anything you do here short of a complete proper replacement has a very high chance of making your vehicle a real road oiler.

 

Ugh. I guess I will see if I can plug and obvious holes in the seal with RTV sealant while the flywheel is off and then plan for a rear main seal replacement in the future once the trans is back in place. Ugh. Thanks.

 

I have no experience with vans... That being said, all the motors I have worked on are balanced above the motor mounts. Unless your mounts are bad, there should only be a bit of settling back. If this is an issue, tie the engine off to something to stabilize it.

I could be missing something here so disregard if this is not pertinent. Otherwise, slowly lower the jack and see where it wants to go.

 

Thanks. I just went out and looked at the van and discovered that removing the weight of the transmission from the suspension made the engine lift up several inches off the jack head. Apparently the engine has been unsupported by the jack for about a week now with now bad effects. At least now I know that I could pull the pan with the transmission off if I wanted to, but I don't really want to. Getting to all the pan bolts would be a ROYAL PITA.

The Timken crank sleeve arrived in the mail today and I don't see why I couldn't install it backwards and gently push it through the current rear main seal. The sleeve is a stamped part so it is a uniform thickness across the entire body of the sleeve. I can't see how it would make a difference installing it the opposite end first. I think I am going to try leaving the pan in place and sliding the sleeve on backwards. Worst case scenario I end up having to pull the pan and replace the seal once the transmission is installed.

 

Its more of a pain in the @ss to drop the tranny again if it still leaks; it could leak more after screwing with it. I would drop the pan, loosen the rear main bearing cap, and put a one piece in. Its more time than anything else.

 

How do I install a single piece seal on my motor? It is designed for a two piece.

 

You know what... I may have just spoken out of my àss... I dont know if you can. You might look it up to see if there is a one piece available to replace the two piece. Maybe post a fresh thread inquiring. One pieces are so much easier to deal with.

That point aside I would still take the time to do the job right dropping the pan/bearing cap and such. Heck it might be a good time to check the condition of your bearings since your in there.

 

The motor was rebuilt a few years back, and runs very well with very good oil pressure.

I pulled the flywheel and made some interesting discoveries. (1) What I thought was an oil leak from the rear main seal as actually a transmission fluid leak. Yay. (2) The engine has been switched to a single piece rear main seal by the engine builder. Staring me in the face when I pulled the flywheel was a big single piece rear main seal stamped National 2377, the part number for the single piece rear main seal. Go figure.

So, looks like no sleeve is necessary since it isn't leaking and the motor has already been converted to a single piece rear seal. Double yay. Now I have to debate about whether to replace the rear seal while I am in there or just button it all back up with no more down time.

 

The question is how old is the seal. Although they can look good, they do get brittle with age. Guess I wasnt talking so much out my àss... Or I got lucky.

I thought I read about folks replacing 2 pieces with a single... Two pieces can be a headache to butt up against each other.

 

The crank and engine around the seal are totally dry and clean, except for a small amount of grime from the trans fluid leak. The seal looks like it is still doing its job very well. It is no more than five or six years old because it was replaced when I had the motor rebuilt a few years back.

Anyway, I think I will leave it be for now and just install the transmission. If it ain't broke, I'm not gonna fix it.

 

You cannot replace a 2-piece seal with a 1-piece without machining the block and bearing cap. If you can drop the oil pan, you can replace the 2-piece seal with the transmission attached. To replace the 1-piece, you have to remove the transmission. I've done this on my 69 Mustang, which has a removable cross member under the engine. I'm not sure about other cars.