Transmission 4R100 & rebuild


Well it happened I lost 4th gear in my Excursion. I wanted to see if anyone had an ATSG book for a rebuild. If not I’ll break down and buy one.


I do not, but perhaps Hiram Gutierrez has done a video? Yep.


I found a book. When I have things down, I’m going to replace my up pipes, rebuild my turbo, put a wicked wheel on it, replace my boots & replace the gaskets on my oil cooler.


Have you started tearing into it already?


No, not yet. I’m going to look at the solenoid since they are PWM style. Maybe I will be lucky, not counting on it though.


I’m out of town til NY eve…if I bring in a table top (10ish gauge steel) would you be up to helping putting together a transmission / engine tear down bench?
I have the table top
I have the USA made h.d. legs
Just need /prefer a side drain and a 1 (front) to 2 inch (side and rear) liquid lip around it to contain any excess fluid from spilling.
Have ball valve for drain as well


I am holding off a little before I begin my overhaul. I did some thinking yesterday of all the symptoms. The idiot light hasn’t illuminated yet. I took it for a spin again last night, it shifted 1-4 without issues. I thought well maybe it’s because the fluid is cold. Drove it to operational temps, floored it back & forth from 3-4-3-4 many times. I did notice that my fuel gauge was floating around quite a bit. This isn’t normal at all for my Excursion. This is making me wonder if my alternator is giving out clean enough power. If by chance there is ripple, perhaps a diode breaking down. I do still get fluctuations in my lights at idle. Perhaps that fluctuation is getting to the PCM & making things act strange. I am seriously thinking of replacing my alternator with a new Napa 130 amp.

Just kinda thinking out loud. Sometimes it helps.


Might also check your grounds from engine-to-frame and engine-to-battery, and have the battery checked under load. Auto alternator output regulation is pretty nasty w/o a nice wet cell to ballast it.

However, it does sound like you might have a rectifier diode going out (or already failed) with the variation at idle.


I checked all the grounds before. I recently added additional grounds. The grounds to the block have star washers, I did clean those with scotch bright. I probably should check the chassis grounds.


So more development. I drove it more extensively Friday evening. Seems once the full transmission case gets fully warm is when OD starts acting up. I can drive it about 15 miles ok. When I hit about 20 miles is when it goes down hill. Good thing is now I have a code. Just fail to shift P0783. I believe that it is in the valve body. Once the overdrive starts acting up, the downshift seems to have issues. Possibly the Coast Clutch Shift valve sticking.


Just picked up my rebuild kit today. I plan on starting taking the transmission out when I get home tonight.


Photos, or it didn’t happen. :slight_smile:


Billet converter. Almost everything. The items they didn’t have was a snap ring kit with different thickness snap rings. I hope that the dimensions are well within the middle of spec so I won’t have to get them.

Basically I got everything to rebuild, even the bushing and trans cooler flush.

I pondered getting a rebuilt transmission, however it would be OEM stock equivalent not a 5k$ updated transmission.


Guessing based on the photos that you are also hoping that the bands are OK?


I got the band as well, It is in another bag. There is only one band, Intermediate band.


So the 15th I started working on pulling my transmission. When I drained my fluid it was darker than I remembered. Well the rain got in the way over the past week, I worked Saturday, decided yesterday I should take a lazy day. Tonight I removed the transmission after removing the exhaust downpipe from the turbo, My arms were too big to fit. Got the transmission and transfer case off. I have to say I hate the design that they did with the crossmember. What a fantastic idea to have the cross member hold the transfer case and nothing on the transmission. That would have made things about an hour quicker had it been the other way around. The next non-rainy/non-cold day I’ll pull it from underneath the Excursion.


I know you are full into this rebuild now, but I had similar symptoms on a Ford Sportrac. With slipping and OD blinking. After doing some research on this particular tranny, I learned that this particular one has a problem with a gasket blowing out between a valve body shim and the case due to the valve body screws loosening. I decided to check it out. So I purchased new valve body gaskets and a new filter and pan gasket. Turned out the gasket had blown through causing pressure drops and some of the valve body screws were loose enough I could back them off with my fingers. So I replaced them and tightened each valve body screw to recommended sequence and ft/lbs and sure enough problem has been solved.


And she is on the kitchen table


The boys obviously take after their dad. Aren’t you glad you bought that comfortable couch?


I thought I recognised that table…