200, 200-4R, and aftermarket servo sizes

jakeshoe

Member
Joined
Nov 19, 2002
OK,
I'm trying to put together a chart of the different servo sizes available.

The desirable servo's are currently the GN, 200 3 speed 134/112 cover piston combo, and the aftermarket billet ones.

I have a GN servo I will measure the 2nd apply area,
I also have a couple of other different sized 200-4R servo's I will also get.
Then I will be gathering 200 servo's to measure as I come across them.

I would appreciate any input from you guys with:
Servo cover and piston number,
2nd apply area diameter,
1 piece or 2 piece,
any other pertinant info.

We'll get a chart going and see what all is available.
 
The Superior/Fairbanks servo is 11% larger than stock.

The Sonnax servo is 17% larger than stock.
 
I'm looking for actual measurements, not marketing numbers.

GN Servo:
694 Cover/562 Piston combo. Apply area 2.675 diameter.

692 cover/ 563 piston 2.525"

569 cover/ 564 piston 2.350"


Anybody have the area for ANY of the older 200 servos, other 200-4r units, and the aftermarket billet pieces?
 
OK,
I aggravated Chris at CKPerformance and got some more info.

200 Servos
133 cover/111 piston is the same as a GN in apply area.

The 134 cover/112 piston is 2.850".
 
Jake, I finally got up to my shop today, and this is what I found:

694 Cover/562 Piston combo. Apply area 2.675 diameter. ---- This one (same measurement too) came on my 84 'OZ' tranny. Is this the early or late GN size?

692 cover/ 563 piston 2.525" ---- The one I have measured 2.538 with my cheap caliper .

134 cover/112 piston is 2.850". ---- This one measured 2.892.

The pistons all seem to be about 30-35 thousandths smaller than the inside of the cover where the seal rides.
Perhaps I'll try measuring again--- I have no idea why they don't match your numbers. Maybe operator error on this end?



Do you know which lip seals (not flat cut piston ring/disc brake style) will work with the 134/112 setup? I'm going to need application and or part numbers and sources when I finally get around to building a trans. for my project.
 
A.G. that's what I thought I measured was pretty close to 2.9 in. ID of the cover. I wasn't sure so I didn't want to spout off.;)

When Chris sent me that big servo it had 1 teflon scarf cut & 1 steel ring & it seem to work just fine.

Jim
 
A.G.
Thanks for chiming in.

I got the old 200 measurements from Chris, so did not actually measure myself.

There does seem to be about .030 between the piston and cover sizes typically. I measured one the other day to see what the difference was.

694 is the 86-87 GN (the best factory 200-4R servo).

The 692 is the 84-85 GN and Monte SS up to 87 as I understand. Better than the smaller ones but not as good as the 694 or larger stuff.


The 134 cover/112 piston I called Chris for a measurement. But I bet your measurement is right on. got any extras of those :)
I need one. I'm working on getting a couple from some core guys but no luck so far.
I may try to have some made eventually.

One thing I noticed measuring is that the pistons are tapered. smaller on the end that goes deepest into the cover and get larger.
So if you measure at the "tip" of the piston you will get a smaller reading than at the base.
That is probably where our discrepancies are at.

No biggie, I am not after the .001" measurement, jsut at least some good rough measurements for comaprison purposes.


As for your sealing ring question.
You might be able to get by with using the replacement sealing rings for a Super Servo... They are lip seals not square type and I think a kit is $9. I'll check if I remember. But we need to know the diameter of each of those....
 
Jim-- i probably shouldn't spout off either, but holding back just isn't in my nature. On occassion I have heard "Thank you for sharing" from management, which is Yuppese for either 'what the **** is he talking about', or 'more information than I needed'.

I checked my measurements with a different caliper, and would guess that they are within a thousanth or two.

After looking once more at the 200 piston and cover, I'm not sure that a lip style seal could be used... the cover has a depression for the pin, which might make the piston itself bottom out in the cover, squishing the lip. I'm not gonna measure closely enough to be sure, but will use a square cut seal (esp. since I noticed that my big cover has a groove worn in it from crud).

Jake, I got my 200 piston and cover from a local independent tranny rebuilder who has beeen around since day one. I just asked if he had any 200 servos stashed away, and he sold it to me for $5. It is scored a little (see above) but it should still work... So no extras, but you have a new line of attack:D .
 
what is the billet servos measurements?you really cant make them any bigger than the 112 because it wont fit into its bore then.btw ,i measured the piston and i was in the middle of ..........anyhow the difference between the piston and cover is made up for by us by installing 4 or revolutions of twined up teflon tape in the groove before installing the seal rings so it fits tighter and seals better.
 
My own and another both went bad in a fewdays of using it, It seems as though the pin was getting stuck in the bore when it got hot. and would creat a 2-3 bind and would not go back into first gear, even manually.Re-placing the servo was the only fix to the problem
 
Interesting...

I acquired another 200 servo with a 2.510" diameter but cannot remember the number... That would be about the same as the 84-5 GN's...
 
Hi all. I know this is an ancient thread, but I can't find this info anywhere so I figured I would post it for future reference for anyone looking.

I stumbled across a 200 servo today. It has a 155 piston and 144 cover. It is pretty big. I measured it with my digital caliper.

144 cover - 2.795" / 155 piston - 2.763"
 
This happened to be in a pile of other stuff I had picked up. Pure random chance. But when I see 200 or 2004r parts/cores I check em out and snap em up if good, you know, for "just in case" scenarios. This one is a keeper.
 
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