Howdy!

I’m in the middle of my first 727 rebuild. I got a kit with kolene steels and raybestos stage 1 fibers. They are the same ones for front & back. Sorry if it’s a dumb newb question but I just did a quick test fit to see how many will go under the ring lands and there seem to be some extras left over. I don’t have experience with this job to know if this combo of parts is standard stuff or if it’s common to have to machine the pressure plate or something to get an optimal gap or fit an extra pair. I have seen pics of the heavy duty drum with more space before the snap ring I have a normal one from behind a late 70s 400 B motor. Maybe a standard kit has enough fibers & steels for the extra tall style clutch pack?

If I understand right I just stack them starting with a steel and ending with a fiber then the pressure plate and then check the gap between the plate and the snap ring. I figure the object would be to fit as many as possible and still get enough clearance for the fibers to spin (without dragging and making heat) when not clamped right?

So would I be going for a stock clearance or a spec that multiplies a value times how many fibers I can fit? Should I measure it dry before pre soaking and lubeing?

I haven’t done any measuring yet just some late night 727 disassembly. There was fine gray paste sludge in the pan so I decided to buy some books and teach myself how to freshen one of these up. Man the rear clutches and steels were smoked! The steels are even a little warped and there is almost no friction material left on them but everything else I’ve examined in this thing is in great shape. I am glad I decided to open this thing up.

Thanks Moparts!

As far as I can remember there where two different 727 front drum sizes, stock and the 1966 and later street Hemi.
Do you have a factory service manual for your car year? if not find, buy or borrow one and use it for the correct specs, you may see "self proclaimed expert people" advising to add additional clutches to a "race" 727 transmission, that is not always the best way to go
As far as how much clearances you want between the clutch and ring retainer I would have to dig out one of the old Mopar race bibles to see what they recommended for each application, BB, SB and Hemi back in the day, which may not apply with todays parts
Are you going to use the stock valve body stock? If so make sure and get the pressures set correctly on start up
If your going to use a kit in the valve body or replace it use the manufactures recommendations on the complete set up

You can get different thickness snap rings, and even a thicker thickness steels to adjust clearances. I think turbo 400 snap rings will also work? I don't know the best place to get them. But this seems like a good price at MACKO:
http://www.makcotransmissionparts.com/A727SnapRings.html

I haven't used the Raybestos clutches, but I'd think the clearances would be about the same as stock?
The rear clutch is not a shifting clutch, when in drive it is always engaged so the clearances can be on the tight side. Factory spec for 4 clutches in rear pack is 0.025" to 0.045" (I just think of it as 0.030" +/- 0.005").
The front clutch engages third gear (a shifting clutch) and the clearances are larger. Factory spec for 3 clutch pack is 0.035" to 0.088", 4 clutch pack is 0.047" to 0.110", 5 clutch pack is 0.033" to 0.075".
Not sure if the tighter spec for the 5-clutch is because it uses all 12 of the return springs, has a higher second band lever ratio, and there is also more material to compress?
Using 0.020" per clutch works well for the 3 and 4 clutch setups (0.060" and 0.080".)
On the 5 clutch, I would still stay on the larger side, maybe 0.060"?
Hopefully someone who does more of the 5 clutch setups will chime in.

The factory uses a thinner fiber in the rear, if the fibers are the same thickness, and are the thicker fibers for the front clutch, you'll have a problem with clearance on the rears.

If they're the thinner rears, then you'll wind up with too much clearance in the fronts depending on how many you try to install.




Front clutch pack starts with a steel but the rear has a dedicated pressure plate on both sides. A good rule of thumb for front clutch clearance is .012"-.015" per fiber disc. Rear can be tighter .032-.035" total. Measure after pre-soaking the discs.

A '70's 400 could have either a 3-disc (on left below) or 4-disc front clutch drum depending on whether it's a 2-barrel or 4-barrel. If it's a 3-disc it would be wise to replace it with a 4-disc or have a new snap ring groove machined into it.

Yup the rear has the steel plate with the lip on it in first- sorry for the confusion. Thanks for the info!

Got a chance to measure these- they both came in five thou over minimum with four fibers in each pack. Time to clean and rebuild everything then I get to have fun with a tf2!

Ok it’s all buttoned up! I installed the tf2 kit and that went pretty smoothly. Hopefully it will run well in my hotrod whenever I get it all built but this was a major item on the checklist.

Thanks again for the detailed and thoughtful responses

Rdr