So I'm rebuilding my 4R70W from my '03 Expedition and the clutches for the direct and intermediate CP are a different design(apparently improved). The clutch packs for the forward and reverse CPs are the same design as I removed. The forward and reverse CPs are w/in tolerance in the drums. The intermediate CP looks close, measuring the new steels/friction stacked against the old ones is only about .010"-.015" thicker on the new set.

The problem is the direct CP. I only get about .030" clearance and it calls for .062"-.085" which seems too far out to ignore. It's all from the frictions. I called the person I bought it from and they didn't think it should be an issue. I called Raybestos and they said pretty much the same thing. When I asked if this would cause excess heat from it, they said w/ the new design it should counteract that and I'm thinking then this will negate any benefit of the new design and cause extra heat in the transmission leading to premature wear. Anyone have any experience w/ reliability and using a close tolerance like that?

Otherwise, I also asked about thinner steels and while they gave me a part number for one that would be .010" thinner, but I'm having a hard time sourcing it (511125). I want to get 3 to put me at the low end. Anyone ever tried to have steels planed by a machine shop to make them thinner? I was thinking that could be an alternative, but I think I would have to ask the company again to see if there's any type of heat treatment on these.

 

You don't want to try to have steels machined. The resultant internal stresses will leave you with what resembles a potato chip sooner rather than later.

Get the right thickness steels

D

 

Thanks for the input!

I opted to get the thinner snap ring which should give me +.028" clearance which will put me at the low end. Ended up having to go through the dealer.

 

So now I'm at .050" on the direct CP and I'm happy with that. I air checked the direct drum and it checks good (after adding some ATF). The forward and reverse are leaking however. I can't tell if it may be the seals or check ***** or something else(maybe just needs trans fluid around the seals). I think I'm going to take the forward piston out again and clean the check ball for starters. It did look like it may have some residual junk in it, but it didn't seem to come off with my fingernail. I read after that I can use WD40 to clean it out. I was also wondering, can just put assembly lube on it to help air check it? Is that typical?

 

The forward and reverse don't seal up as tightly as the direct does. Whether what you have is too much leakage, I can't tell you.

D

 

Thanks, there is some residual material in the checkball in the forward drum. I don't think I'm going to be able to clean it all out or at least verify it is and I would imagine that would ruin the forward CP if it didn't seal good enough. So I'm thinking about upgrading to a Sonnax drum. Looks like I can get one w/ shaft installed for $200 and $125 w/o. I'm debating if I want to hassle w/ the shaft. Didn't mess with the reverse drum yet.

 

On second thought I took it apart again and tried cleaning it out with a toothbrush and compressed air. I can see more than I thought and tried cleaning it the best I could. I can still see a small amount of sediment, but it doesn't want to come out. I reassembled it and tested it out. The checkball seems to be holding well. It actually seems like the seals on the input shaft and stator are what's leaking not the piston seals. Maybe I should just reuse it.

 

After more deliberation I decided to get it. It was $150. The math makes sense $150<$2000. Now hopefully I can get the shaft pressed out and in without a problem.

 

So I was able to get the shaft pressed out and in. You definitely need access to a hydraulic press. It took about 4 tons of force to get it where it needed to be and that's w/ the general lube it calls for. Built up the unit and put the pump on. I noticed when bolting it down (even without plastic thrust washer) it felt like it was compressing something it shouldn't. I took it apart a few times until I realized it was the return spring cage for the intermediate piston which makes since. Nothing I saw or read let me know this. Glad I finally figured it out and didn't damage anything. It also takes a good amount of force to move the input shaft especially with solid rings to find out what the endplay is. I ended up using a ball joint splitter going through the bottom hole in the bell housing to move it. I found that I had .080"-.085" endplay w/ no washer and the red one that was originally in it was .104" so I ordered a new set. The local dealer failed to find the thrust washers so I had to get them online. I don't know if I found the right spec, but it looks like it's supposed to be .010"-.040" after the washer is installed. They call it the torque converter end play. There was nothing else aside from that I could find for the endplay spec. I also ended up ordering a new direct drum and changing it and I'm glad I did. I didn't see cracking where the snap ring goes, but it looked like some of those indentions for it were fairly deep and had me worried. The new one looks a lot better and I feel more relived. The design is a little different though, but everything fits as it should. In addition I just bought solid rings for the output shaft where the direct drum rides. This should be a fairly strong transmission when I get done with it hopefully.

 

So I'm kicking myself for only ordering 2 solid rings for the output shaft (requires 2). They were only $2 a piece and shipping was $8. I had a hard time getting them to size right once I got them in and it tore the top edges off trying to get the direct drum installed. I'm just going to stick with the split rings. they seem to seal fine. hopefully I can get it rebuilt this weekend.

 

yeah, you need the specialty tool to install and re-size the solid rings.

 

Thanks for the info. I saw a plastic resizer used on one of the videos and I could probably make it with my 3d printer, but the main video I went by they didn't use it so I didn't. I did try using something that was 3d printed and a hose clamp to resize it and it didn't seem to work because the hose clamp seems to deform it before it gets totally tightened.

 

So it's finally rebuilt as of yesterday! I put on the torque converter just to make sure it went all the way on. After I was able to fully seat it it didn't want to come back off lol. Finally got it though. I will post if it works when I actually get it installed and tested. The torque converter is empty so I'm just going to adding 2 quarts of fluid.

 

I finished the install and serviced the transmission fluid. 14 qts and some change added since I flushed the lines too. I still have to do a final check on the level.

First time I took it out it wasn't shifting into second until RPMs were around 2500-3000. The odometer also showed just dashes and O/D was flashing. Started fine and all gauges worked except odometer. Only had P0720 fault (I have a code scanner). I was already suspecting The OSS was bad because I pulled most of the components out of the transmission w/o pulling the sensor so I thought it may have been damaged. Bought a replacement OSS sensor and when I went to change it I noticed the connecter wasn't clicked in and pulled off. I reconnected it and tested it out. Everything worked after that! All gears work! I thought the shifting would be a little firmer.

So I had some issues trying to find the OSS at a local parts store. Even the dealer didn't have one in stock. Then my wife chimes in...
Wife: What's wrong?
Me: I can't find a store that carries one of these sensors in stock.
Wife: You know you only need to find one store that has one.
Me: Thank you for your wisdom. I thought I would have to find at least two.