Does anyone know where to get GM #8667668? Forward clutch backing plate .250 - .255 thick.
I have .077 clutch pack clearance and would like to tighten it up a bit.
Currently have .090 steels, .170 apply plate, and .225 backing plate.
Also have the .070 wavey plate installed.
I suppose I could replace the wavey with a flat .090 steel.
Thanks for any helpful knowledge!

 

Try Teal Automotive in Dunkirk Indiana for the pressure plate. Ask for Sheryl. Otherwise you could use the early forward clutches (.080" thick instead of .070"). DO NOT eliminate the waved steel. You will not like the engagement when you put it in a forward gear.

 

Thanks for the reply and information. While I have assembled the forward clutch over a week ago, and have moved on to the next part, I believe I ended up using .090 steels, with the wavey plate, and I found a thicker flat plate in my pile of crap that gave me .045 stack clearance. Not sure where the thick flat plate came from as they are not listed in the assembly manual. Possibly from a later 4L60E? Also, I don't remember what thickness frictions I used.
Thanks again.

 

Are you talking about the flat plate that sits on top of the overrun clutches? There are two different plate sizes. Approximately .140" and .170" respectively.

 

Using the blue ATSG assembly guide, early and late version as a reference, here is what I had/have.
Late manual list the forward clutch as having one apply plate @ .169. I called it a flat plate. That is what was installed in my original tear down stack.
They also list the frictions @ .070.
The backing plate is selective per the late manual. The one I could not locate easily.
My stack up had excessive clearance, so I found a thick apply plate @.251, in a pile of left over parts I had, which fixed my problem.
I later found the.251 apply plate called out in the early manual.
The frictions are also listed @ .070
I forget what my frictions thickness are.
So, the manuals list a .169 and a .251 apply plate.
Frictions the same @ .070
I do not doubt your word as I am sure there are many variations of stack ups available.
But so far that worked for me.
On to the reverse drum.

 

Yes, there was a thicker one in the very early 700R4's. I rarely used them except in the very beginning, as I changed the early way of the forward stack up to the later way of doing this. The early way had a waved steel making contact with a clutch, which wore that clutch out sooner than the rest in this clutch pack. Starting in 1987 they changed to the late way of doing this by installing a waved steel sitting against another steel instead of a clutch. Which was a better idea, and the waved steel almost never needing to be replaced. The .170" became standard, with the rare occasion of the .140" plate which was used against a much more (taller) waved steel. I have interchanged these as necessary to get the desired clearance needed/wanted.
As for addressing the reverse input drum problems. Here is a little history. The feed/bleed system was introduced in 1987 in the reverse input drum. The steel apply piston was replaced with a larger diameter aluminum piston with the feed hole in it. The aluminum piston being lighter prevented "run on" on the 1-2 shift, and more noticeable on a high rpm quick 1-2 shift. The heavier steel piston would wear into the drum, and again excess metal being produced and the clutch clearance changing. The waved steel was replaced with the Belville (dished) steel, which covered the feed hole in this aluminum piston on apply. This dished steel created a lot of wear in this drum from oscillation when the clutches were not applied, and a sometimes no reverse condition. GM in the mid 2000's introduced a dished steel that has a few teeth missing from one side creating an imbalance that was supposed to eliminate the oscillation. It did some, but still excessive wear in the drum. In the early 1990's, I got rid of the Belville (dished) steel and replaced it with the original waved steel (the waved steel does not oscillate) that was used in the early 1982 - 1986 drums. I have to use the early .080" thick reverse input clutches to keep the clutch clearance within range. The later clutches are .070" in thickness. There are several different thickness pressure plates for the reverse input drum. Ranging from apx. .235" - .285". I change the steels to the late Turbulator steels (introduced in 1996) as these offer less friction (parasitic loss) when not applied. As for the hole in the aluminum piston. Leave it alone in most cases. By restricting it you get the unwanted partial apply at higher rpm (due to centrifuge) which gradually burns the clutches up. You will see this when a transmission comes in that has a restrictor in this hole. The steels will have hundreds of Leopard spots on them and the clutches are burnt up. Minimum hole size in this piston should be .076" and a maximum of .096". IF this restrictor is installed in the piston. Drill it to the suggested numbers. If you are going to go over 5,500 rpm on the WOT shifts, the larger number feed hole should be used.

 

Thanks for the tips.
As far as the forward clutch goes, yes, I looked at the wavey against a friction and just said to myself no way am I doing that, so I didn't.
Wavey against a flat steel, then friction.
Reverse drum: I have some experience with this one, but more info is always appreciated.
I had to replace a drum once and could not find the same one. Forget if it was old to new or new to old? Something about the size and shape of the oil feed hole in the drum itself. Round to square, square to round?
I took notes when I went through this so I can refer to them if need be.
Ended up putting a set screw in an oil feed hole where the pump mates up to case, then drilling out a small hole .096(?), have to check the notes.
Tip from guy at Sonnax. Put many miles on that trans and no issues so far.
Anyway, it's always a learning experience when I do one, which makes it fun.
Thanks for the help!

 

Yes, the Feed Orifice for the Reverse Input Drum Circuit has changed through out the 1982 - 2013 life of the THM700-R4/ 4L60E/ 65E/ 70E.

In the Early (1982 - 1986) Units the 0.095" Feed Orifice was in the Stator Support Shaft, and the Reverse Input Drum just had an open Passage in it.
In the Late (1987 - 1993) Units the 0.095" Feed Orifice was moved into the Reverse Input Drum, and the Stator Support Shaft now has an open 0.215" Passage.
In the Electronic (1993 - 2013) Units the 0.095" was moved again, now to the Valve-Body Separator Plate, the Reverse Input Drum has an open "Square" Passage, and the Stator Support Shaft also has an open 0.215" Passage.

Now the Reverse Input Clutch Stack-up that Dana/ @Pro Built Automatics posted works very well.

My Father and I have used that configuration with good success.
However, years ago, during Trans-Brake Testing we found room for improvement.

We are trying to fight centrifugal forces... they cause the ATF to be pushed out to the very edges of the Clutch Drum.
But the Bleed Hole in the Apply Piston is NOT near the edge of the Clutch Drum where the ATF is being forced to.

So we Plug that Bleed Hole in the Apply Piston.
Then drill a 0.060" Bleed Hole in the very outer most corner of the Clutch Drum sealing area at a 45-Degree angle into the 90-Degree walls.
This Bleed Hole goes through the Clutch Basket, but not entirely through the Drum.

Next we drill the outside of the Clutch Drum for a new THM400 Check-Ball Capsule from Sonnax...
The same way that the Early (1982 - 1986) Reverse Input Drums were produced.

Lastly stiffer Return Springs are used for the Reverse Input Clutch.

For actual Trans-Brake use there are some additional steps taken.