Part Two - Input Drum and Final Assembly

Torque Drive Input Drum

Here you can see the Torque Drive Engineering Mods on the drum. They press a spacer over the shaft (arrowed) to re-inforce the area around the stator shaft. The piston is machined out larger to fit over the sleeve (right piston is the TDE one). Dont bother buying the proper lip seal installers as neither of them fit.

It is at this point the ATSG manual is unhelpful. It says to put the steel piston into the case and then insert the forward piston on top. This in my opinion is impossible as you cant guide the lip seal into the steel piston. So my way is to attach the steel piston to the back of the forward piston and hold it in place with plenty of jelly. Then use the peice of mylar to guide the inner seal over the drum center.

The overrun piston can be simply guided into place, because the TDE modified one uses an O ring instead of a lip seal. (otherwise you could use the mylar sheet trick again)

Here's the stackup the the PATC 8 plate clutch pack. Gives about 65' clearance

The pistons can be air-checked by GENTLY blowing with an air line, be very carefull as you can easily blow the seals out.

Front pump selective washer selection

To make life quicker and easier, remove the o-ring from the front pump and dont install the reverse input housing. With no reverse input housing fitted it's possible to use a screw driver to lift the drum up and down to check the clearance. (where the selector shaft would go) Changing washers is quick because you only need to pop the pump out and change the washer directly without having to keep reassembling and re-alinging everything. I set the clearance to about 18-20'

Valve body rebuild

Cleanliness is key here. The body is stripped down, carefully laying everything out and washing it all down in powerful solvent (Tric)

I fitted pinless acumalator pistons. They use Teflon rings like the input shaft; I found that the housing made a good rezing tool. Poking a screwdriver through the hole in end allows you to get the pistons out before blocking the hole with a ball bearing.

Vavle body goes back on, along with Super 2nd and 4th servos.


Update - fitted transmission this weekend - works perfectly. 6/2/2006

Still holding. Done about 500-600 miles. Fluid is good, no burning. (I dont do many miles in this car, but what miles it does are quite hard miles i.e. blasting round town on a sunday afternoon then putting it away again.) 20/4/2006

Still working. Done 1100 miles now. Pulled the pan off to re-fit the temperature probe, no nasty suprises - oil in good condition. Now officially my longest lasting 700r4!. Fingers crossed it continues to work.

Ive also rebuilt my '85 box to the same spec (except for the 5 pinion plannets and hardened input shaft) - to have as a standby unit - I missed a few shows last year due to downtime on the box - dont want a repeat of that.


Update - transmission 1 year old - completed over 1800 miles no issues.


Update - Transmission Failed. Alto 8 Plate 3/4 pack burnt out - lasted 2300 miles, 18 months - so best performing box so far.

Looks like the lowest pressure plate has cupped, causing all the other steels to cup - causing uneven apply pressure. Difficult to determine what come first, cupping due to heat or cupping through mechanical weakness causing uneven apply pressure - then causing heat through slippage.

There appears to be some confusion on the correct stackup order for these clutches. Dont assume this is the correct order:


Refitted my spare 400BHP spec 700r4. This was built as a standby unit to the same spec as above, but std input shaft and std 4 pinion plannets. Works at treat and ive cured a 3/2 downshift problem it had before the rebuild. It has the same shift feel as my 600bhp box, so the combination of parts is clearly good. (And I've got the knack of assembling them!) 15/04/2007

600BHP Spec box back in. I Replaced the burnt alto 8 plate clutch with a Raybestos Z-Pack. I dont have any photos, but it replaces the entire 3-4 stack, which inlcudes a very thick custom base plate - which definately wont warp and now Refitted the box. Lets see how long this one lasts. 20/1/2008

Done 1000 miles on the Z-pack, no problems so far. 30/8/2008

Done 1700 miles on the Z-pack - still fine. 27/5/2009

2500 miles on the Z-pack - still fine. Even managed some off-roading and high speed run at Milbrook!