I have a question for you transmission gurus out there. I just recently bought a mint 1994 F-150 with a bad motor and 4R70W. The engine has been pulled and sitting in front of the truck along with the transmission outside in the elements for about 5 years but the owner said it shifted and drove perfect. Supposedly has a shift kit in it cause it had a firm shift, not harsh but firmer than stock but no miss gears, high revs etc. The transmission dipstick has been in the filler tube the whole time but here is my dilema.

I have a 351W that will be replacing the 5.0 but worried about the power the 351 will make. It is bone stock and I'm not looking to building it right now so stock power level maybe less. I was told that the clutch steels can rust where they are not submerged in transmission fluid and that when you begin to drive, this rust is rubbed off, wears friction material, jams valve bodies and just plain destroy the transmission. Is there any truth to this or complete BS?

I planned to drain the pan to inspected the fluid and fill up, drive it about 20 miles then drain and replace the filter and fluid. I'll flush the cooler at the same time. I actually wound up with (4) 5 gallon buckets of MERCON/DEXRON fluid so figured I could burn some up flushing the transmission.

I've heard the E40D transmissions are pretty stout but I don't know anything about the 4R70W transmissions, are they pretty good transmissions or are they problematic? I don't drag race or romp anymore, got that out of my system years ago but would probably tow an 8N ford every now and then and lawn equipment regularly on a single axle 6 x 12 utility trailer.

Thanks in advanced for your help.

 

4R70W transmissions are good units. No one can tell if yours is damaged from exposure.

It should handle the bone stock 351w just fine if it's in OEM condition.

 

That could happen.

 

Safe: assume it did

Gamble: run it

 

Is there anything I can do to prevent total failure if this did happen, maybe service as I laid out in my earlier post, or is a teardown the only way to tell?

I'm trying to build as cheap as possible but quality comes before saving a couple dollars, I've been around long enough to know better as well as being on the wrong end of the equation.

Hey Mark, I see in your sig that you are/were a Ford transmission engineer, did you have anything to do with the design of this transmission. What would you do if this was your transmission?

 

No, I didn't work on the 4R70W. If it were mine I'd open it up and find out if it were rusted inside.

 

Might take this opportunity to learn how to build an automatic transmission. I have some mechanical skill and deal with seals o-rings in hydraulic pumps and motor from time to time. Will definitely find a good manual that can guide me through the tear down process but will scope youtube to see what I have in store. If it looks like more than I'm up for, I'll have to find a good transmission shop to do it for me, but I'm always up for a challenge and to learn me something.

 

You can get a good manual at https://www.atsg.us/atsg/.

 

Well I just got done looking at a youtube video showing tear down, testing solenoid resistance, etc.. Going to buy a manual and give it a shot. I saw the ATSG manuals, that's the one I was going to get. Could be wrong but looked like a bunch of snap rings and gaskets, saw some o-rings and where some seals were, but looks like it would be doable with a good manual and a clean work area. Thanks for the support Mark (hence you can get a good manual vs. you should take it to a professional).

Did you have a brand or manufacturer that you preferred other than Ford for an overhaul kit?

Thanks for all your help!

 

I read through some other posts and think I'm going to contact Oregon Performance Transmission and order one of their kits along with a manual. I'm pretty confident I can pull this off, probably be around 500.00 total so about the same price as a used transmission but I'll know whats inside. If not I have to have a pro do it but I'll at least give it a shot.

 

I've used several kits from www.transtar1.com.

 

Like everyone has stated, it's best to look it over. Not only contamination, gummed up from sitting, dry seals and so on. I recently did a chevy 4L60E for a friend; he got the parts from Oregon. I was shocked at the price, cheapest I have seen. Same parts I get from VTP or Transtar. They included parts in their overhaul kit (mostly bushings) that I had to buy separately from other suppliers

 

Well got the truck home today and got around to checking the transmission out. Tipped it on it's side and about a gallon of water came from the dipstick. Just sat it back down and walked away. In the process of cleaning up the shop from the last project (8N tractor engine overhaul), soon as I get the bench cleaned off, the transmission will go on and the pan will come off. First impression is just junk it and go find a used one or buy a reman, but I'll make my decision I guess once I get in it.

 

If it helps, I had a visceral reaction to your post.....

 

Yeah, so did the transmission when I turned it on it's side ha ha. But who knows might only be in the pan and never reached the valve body.