I just finished rebuilding a 4R100 to put in my 2001 F250 4wd. I didn't want to rebuild the old transmission because it still works and I don't want the truck down. I found a 2wd transmission five years ago and picked up the parts to convert it to 4wd. It then sat until the middle of March. I get accused of procrastinating, and I guess that is right!

First I built an adapter to bolt the tranny to my engine stand. I used some 2x2x1/4" angle iron I had lying around. I used the transmission case to jig up the bolt holes and position everything for welding. I chose to use four 3/8-NC and two 1/2-NC threaded holes on the driver's side of the case. I discovered that by off-setting the transmission vertically I could avoid interference with the engine stand components. I was able to remove the shift arm with the case on the stand. In practice, the arm can be removed and replaced after the case is removed from the stand for cleaning and inspection, so it really doesn't matter.

Attached are photos of the adapter I built. It balanced pretty well during all phases of the rebuild, and I never had much problem with it trying to get away even with the short bar I was using.

 

Pulling the pump was pretty straightforward. I bought a 3-foot section of 10mm all-thread and cut a piece about 12" long. The two threaded rods screw into holes in the pump that are threaded for that size. I drilled a piece of scrap wood 9-7/16" apart with 1/2" holes and used nuts and washers to apply the pressure. I like this better than banging on the pump with slide hammers like the books recommend.

 

When I assembled the transmission, I used the ATSG manual, but also had the Ford Service Manual on computer. When I got the point of assembling the center support, I remembered Mueckster's post about checking stack-up on post #29 of this thread: https://www.ford-trucks.com/forums/1...l#post13762611

Sure enough, I hadn't got the shell assembly just right and had to reassemble it properly to get the clearance right! Thanks, Roland!

When I checked the reverse end play, it was within limits but greater than I wanted. I found that there are reverse clutch steels available in 0.081 thickness, which is about 0.010 oversize. By substituting three of these, I got my clearance down to about 0.040. I bought these from Oregon Performance Transmission, and I received Raybestos brand steels in two days.

Installing the coast clutch assembly requires a special tool according to the manual. I found that by putting a #6-32 screw near the end of a piece of 3/4" EMT electrical conduit and grinding the head to where it would fit in a 1" hole, I could insert it through the bushing in the coast clutch assembly, line it up with one of the two large grooves in the splines below, and with a 1/2 turn, be able to pick up the assembly. I was able to use this to drop the assembly into the transmission, but had to be careful to keep the drum from being pulled upward when the overdrive clutch discs hung up on the drum. It went together well on the third try.

Here is how I did it:

 

The coast clutch on a 4R100 has to be deep enough into the transmission to allow the pump to set in full depth. You can see through the drain hole in the case just to the rear of the pump intake and tell if it is seated deep enough. It needs to be a little below (behind) the front of the opening in order to be sitting properly.





As you can see from the photos, it depends on where your eye is in relation to the opening, but it needs to be at least flush with the top (front) of the opening in order to get the pump installed properly.

 

Good visual!
IIRC, the top (thrust) surface of the Coast Clutch-OD assembly should approximately .200-.230" below the pump mounting surface (where the gasket sits). This will tell you whether the upper portion (center support up) is assembled correctly.

 

I found that one of the most difficult jobs was removing the little snap ring that holds the output shaft to the reverse drum. You are working down deep into the transmission case and then the ring has almost nothing to grab. I think if the ring has been re-used, it may be rounded-off a little, which makes it harder to get a grip on the ends. For sure use a new snap ring in this position.

I was using a pair of New Britain snap ring pliers designed for this type of ring. I freshened up the edges of the jaws and also the checkering in the tips, and it still wanted to slip off! I found that placing the open ends of the ring about the 2 o'clock position was the best ergonomic place. I also found that pushing the output shaft up into the transmission as far as it would go helped get the ring off the back of the drum and gave the plier jaws a little better chance to grip.

I want to thank everyone who has posted about their 4R100 experiences. They made my project go much easier that it would otherwise. They also gave me the courage to attempt the rebuild.

Since I don't expect to increase the power of my truck (perhaps a tuner with 60T and 80E settings, at most) I didn't use hot-rod clutches or hard parts. Since my input shaft showed wear on the splines, I did buy a 4140 billet shaft off ebay. The tranny I used was a 2wd version built in Dec. of 1999. It had 4-pinion planets in the rear two spots, with aluminum housings. I upgraded to 6-pinion planets, a 45-element direct sprag, Sonnax snap ring repair of the center housing and a one-piece rear case bushing. I used the Sonnax center support shim, converter aluminum drain-back valve kit, cooler bypass rebuild kit, and the rubber seals for the intermediate and direct clutch circuits. I installed the entire Transgo Tugger kit, including the improved spiral snap ring for the overdrive return spring and the locking snap ring in the coast clutch. I kept the holes in the metering plate on the small size until I see how firm the shifts are.

I used oversize (wider) snap rings in the direct and overdrive clutch packs to get the proper clearance. All my clutch packs are in the middle of the clearance range or less, so I should have little delay in shifts.

I replaced every bushing and thrust washer in the transmission. They all were in pretty good shape, but I intend to keep the truck and drive it for at least ten years. Because of that, I was very picky about assembly tolerances. I did reuse the Torrington thrust bearings because every one felt very smooth and showed no wear.

I found that if I penciled in reminders in the ATSG manual to install the Sonnax and Transgo parts at the right time, it kept me from having to go back and redo something.

I am using a Roadrunner low stall, triple disc torque converter. I run around at 8,200 GVW normally, and tow a 10,000 lb. trailer about 60 miles a month, so it shouldn't get too big a workout. Although I haven't seen transmission temperatures above 170 degrees yet, I'll be adding a larger cooler and an in-line filter when I do the swap.

I hope to get a chance to do the swap in the next couple of months. I have another engine to swap in at the same time and hope to get rid of the injector knock on #7 cylinder that I haven't been able to fix with injectors, UVCH, IDM, HP oil system fixes, and fuel crossover/regulated return. It should drive like a new truck when I'm done!

 

I have a large pair of Snap On snap ring pliers for that pesky output shaft ring. I always replace it, too.
Sounds like you did her up right.