I am in the process of rebuilding my 1977 C4 transmission and I am now putting the tranny back together. I am at the point where I am installing the pump assembly and have the pump seated and I install the pump bolts and as soon as I start to tighten the pump bolts I noticed that the input and output begin to bind up and no longer turn by hand. I have taken it all apart a couple of times, but I have not determined why the pump is causing the tranny to bind up when I begin to tighten it down. Anyone had this problem before and have any words of wisdom? Thanks.

Jim

 

Am I correct that you should be able to turn the input and output shafts by hand after the tranny has been reassembled? Thanks.

Jim

 

Both shafts should turn.

You either have a washer out of place or a clutch plate not engaged properly.
Take it apart and start again.

 

Stuart, I think the thrust washers are fine, but I think you may be right on one of the clutch plates not being engaged properly. I was reading my Haynes Tranny manual last night and they say when you assemble these clutch packs to make sure the clutch plates are all aligned and when the sub assemblies are put together you need to turn the outer drums to make sure you engage all the clutch plates. I thought I had engaged them properly, but I can not find anything else that might cause the binding issue I am having. I started out only partially rebuilding this C4 tranny to take care of some leaking issues and I keep getting farther and farter into this rebuild. I just about totally disassembled the tranny and cleaned it inside and out. The only part I have not disassembled are the two clutch packs, since I do not have special tool to take them apart. I ended up replacing the one-way clutch rollers and Springs, the Intermediate and reverse bands, and the thrust washers. The tranny has approximately 113,000 on it and I am wondering if I should breakdown and replace the clutch plates while I am at it. Do these clutch plates usually wear out and need to be replaced at this type of milage? Also is there a way to disassemble these clutch packs w/o buying the special tool? Thanks.

Jim

 

Well I found the problem and I blame myself and my Haynes Ford Transmission manual! The problem turned out to be the metal sealing rings on the transmission pump. The manual tells you install the 4 sealing rings and in the proper grooves, but failed to point out that the sealing rings are of two different depths. All four rings have the same thickness and OD, but slightly different IDs. When the manual said make sure they are in the proper grooves I saw that the pump sealing shaft had 4 smaller grooves that matched the sealing ring thickness and two larger grooves that were not meant for the rings. So I thought they meant put the rings in the 4 smaller grooves and not the two larger grooves. Upon closer inspection I found that the two lower ring grooves were slightly deeper than the upper two ring grooves. I had one of the larger depth (smaller ID, but same OD) in one of the upper ring grooves and it was preventing the pump from sliding all the way into gear train and when I started to tighten the pump bolts it caused the tranny to bind up. Now that I have all the sealing rings in the correct grooves it went together perfectly with out any binding issues. Now that calls for cold one!

Jim

 

Good that you could figure that one out by yourself, that would be a tough call.