Myself and another mechanic friend just rebuilt a 4R100 that sits behind my 2000 7.3l. we are having some issues and if anyone has any thoughts, advice, or things to consider to help us solve them we would very much appreciate it.
To start off, the forward clutch drum had the spline teeth sheared off which is what put the transmission under the operating table. A rebuild kit was ordered from Sun Coast Diesel tranmissions, a new OEM torque converter was purchased and we had a donor E4OD from a 5.4l F-150 to rob parts from. I also purchased the ATSG rebuild manual.
Everything went real well and we used the forward clutch drum as well as the pump from the donor transmission to complete the build with the new parts. The first 2-3 miles of the test drive went well, but upon excellerating for the third time it no longer wanted to shift into third. We than found out reverse didn't work either. Back at the shop, we found the wheel speed sensor (located on top of the bell housing) had wiggled it's way loose due to a missing bolt. That was tightened down and the fluid was triple checked. The transmission still doesn't seem to go into third gear (past 30-35 mph) and reverese is sluggish at best. We can get a couple feet of backup if we drive a foot forward and than put it into reverse.
Our only current thought is the oil pump not working quite right. Does anyone else have any thoughts? Thanks a lot!

 

I think it is a problem with the direct clutch. Direct is used for both 3rd gear and reverse. How would the pump work in 1st and 2nd and then not work in 3rd or reverse?

 

I would check the direct clutch accumulator valve in the accumulator valve body, if it hangs up it can keep the direct clutch from working properly.

This is about the only thing I can think of short of removing the transmission and checking the direct clutch itself.

Good luck.

 

Thanks for the advice and we will check the accumulator valve.
Here is my current hypothesis as to the pump being bad. My buddy bought his f-150 (donor transmission) knowing the clutches weren't good. His transmission just recently went out, giving me parts. We all assumed it was just the clutches, his truck worked in the morning and pretty much hardly moved in the afternoon (and with him knowing upon purchase that they were going bad). I remember him saying that he heard a squeal at times from the torque converter or that area when he tried to drive it. Yesterday, during a test drive, I heard a squeal at times coming from that area, but I tossed that away not giving it much thought until now (I read on a website that the pumps will squeal when they aren't working too well). I think the reason that my truck moves a little and his didn't is because I have brand new clutches and some of his were toast. So if the pump is hardly working AND the clutches suck, you have a very sluggish transmission at all times. However if you put that crappy pump in front of new clutches, those might provide enough grab to move a little. Say maybe 1st and 2nd? Which also are the gears meant to limp you home when the transmission starts to fail. I could be wrong on this and maybe someone is laughing, but thats why I'm bouncing it off of y'all. Thanks again!

 

There is no truth to that statement.