Hey guys,

I'm slowly starting the process of restoring my 1990 f250 XLT Lariat. From what I can tell so far I've got the 351w mated to an e40d. I've owned the truck about eight years but to be honest have been real bad with maintenance due to some past financial troubles and lack of a decent place to work on her. With all of that out of the way now, and having a garage, I really want to clean her up right. She only gets driven around 6k a year for hauling, as i have another car for daily driving.

Now, first and foremost is under the hood-the engine leaks like a sieve. It has about 93k, and I'm just wondering at this point if I need to replace her or just get her properly gasket-ed back up right now. Does not seem to have a lot of trouble running, other than a surging idle every so often that a tap on the accelerator stops. Sadly, I had to park it on grass a few years at my apartment and it has taken it's toll on some of my brake lines, etc. What else engine-wise can cause trouble due to this?

Other major problem is my transmission does not seem to fully engage into reverse at times, or it's slipping. It's weak backing up, and on a slight hill it will just sit there at full throttle and not move. Even on the flats it will labor and not want to move. Sometimes pulling it out of R and back in will yield better results. Other times it will force the engine to stall out.

My local U-pull yard has good deals on both engine and tranny, but I'm wondering and worrying about inheriting similar or worse problems. I can get an engine for $65 on Sale Week and a tranny at $25. Do I go this route and have them both rebuilt before dropping them in, or take my chances? I have just enough room that I could most likely store a spare block and tranny, thereby always having one ready. Down the line if i need to replace again I'd probably drop the original back in place with a rebuild on it.

I plan on being buried in the truck as it is a family heirloom. Cost is not as much an issue as a few years back but I'm also driving it cause I don't like car payments. As far as skill, I have taught myself a lot by doing, reading and most importantly watching and listening to pros. I have access to knowledge up to and including Mechanics at my local dealer, and a more skilled set of hands and squash from my neighbor . We have the ability to pull the block and tranny once we are up on everything we need to know.

Where do I start with this thing, and what other info do you need to help me out. Thanks in advance.

ehmbee

 

Well if the engine still pulls well then there isnt a need to rebuild just because of leaks. You can get to most if not all the gaskets with the engine in the truck except for the rear main seal on the back of the block on the crankshaft, and the oil pan gasket which can be worked out with a little convincing. The tranny sounds like it would benifit from a rebuild, but I would try to adjust the linkage by the placing the lever on the column and the lever on the tranny both in reverse and seeing if that corrects the issue. Your throttle body and linkage sound like you need to check for binding but a vacuum leak can also cause a high idle. I would recommend replacing vacuum lines during a re-gasketing of the block.

 

With regards to ur E4OD tranny, I had the same problem with it slipping and basically wigging out in reverse. I changed the tranny oil, filter, and gasket (the filter/gasket come in a kit) and it now runs fine. Im sure its not a perminant fix, but it runs without flaw (absolutly zero slipping/popping, etc...) so I would reccomend at least trying that before you fully replace the whole thing, as that tranny is heavy...

 

Thanks for the advice thus far, guys-I am pretty sure the rear main seal may be one of my problems-every so often (maybe once a year) when I am on a hill with a load and try to accelerate hard, she will spit oil smoke like I'm fogging for mosquitoes. I had thought it was my valve cover gaskets at first, which are also leaking, but a mechanic friend had suggested the rear main seal. How hard is it to replace? I thought I read here that involves dropping the tranny.

As for the tranny itself, I am sure it is overdue for a filter/fluids/gasket change. The original owner, who sold it do my dad, did pull a fifth wheel camper with it, albeit only for one summer (before buying a new RV). It's never been plowed with, and quite honestly the worst damage it has ever sustained has been by my own hands-Dad kept it garaged and had a three-mile commute to work.

I am thinking I can service the tranny fluids, etc. by myself, and having done motor mounts in my car, jacking the tranny or motor would not scare me depending on what i need done for the rear main seal, but I guess it depends on what else is involved. Thanks again for the advice.

ehmbee

 

My rear main seal leaks as well, you have to jack the engine to fix it, I personally just top up my oil about once a week cuz i dont have a jack and dont wanna spend $500 at a shop to get the work done.

 

Well when the truck sat on the grass it was one thing. Now with a paved driveway the oilstains are quickly becoming like an inkblot test....what's really scary is I'm starting to SEE stuff in them....

ehmbee

 

Your year model of 351W should be the one piece seal. That requires removal of the heavy tranny, ~250 lbs, and the flex plate to get that removed and replaced or removal of the engine from the truck. Pick your poison on this one.

 

OK so if i understand you...I need to remove the tranny to get to the rear main seal...I would also need to remove it to get to the flex plate, or removal of the flex plate is required for seal replacment? I'm not getting your meaning, I think, regarding the flex plate. What is the function of the flex plate? On my mercedes one takes the place of a U-joint on my drive shaft. Is it likely to need replacement also (in the truck, not the mercedes)?

Also, does my rear main seal being bad allow contamination of the transmission with engine oil, and could that be attributed to some of my transmission woes?

I outweigh the transmission so I'm not TOO worried about that part, and I'm a Utility Lineman-plus I have help, tools, etc. to do that safely. I would like to get a lot of this done in one shot, say, like a long weekend. I figure I should be able to get the rear main seal, swap the trans filter/fluid and clean the screen, and maybe get to the oil pan gasket and valve cover gaskets with a week's worth of work. Am I thinking too positive? Thanks for the help yet again....

ehmbee

 

The flex plate is what you could call the flywheel without all the mass for a clutch to attach to, because the torque converter now takes place of the flywheel mass. The engine oil leaking out the rear main seal will not contaminate the tranny as it would on a manual transmission due to the torque converter is sealed to the transmission by a seal on the front of the tranny that the torque converter slips into the tranny. The torque converter should be attached with four nuts on studs sticking out the front of the torque converter. When you reassemble, take care that the bolts go through the correct holes on the flex plate as this flex plate is the same used with a C-6 so one of the holes is a drain hole for the torque converter of a C-6, an E4OD drain is on the side of the torque converter which drains out and access hole on the bottom of the bell housing.

 

OK-now it all makes sense, thanks.

ehmbee

 

If you do have a main bearing/seal leak, the oil will be inside the bellhousing, (easily checked if you have a torq-converter drain plug access.

If the oil is all over the back of the pan and the front of the bellhousing, then it is only an oil pan leak.