Moving Transmission Clutch-Pacs Around.

[BC847]

Hey folks. :)

Over a year or so ago I rebuilt my A518 [46RH (NON lock-up 3-speed w/OD)] and increased the Clutch-Disk/Steel count in the forward and direct assemblies along with a bunch of other crap. OK, fine.

Trying to make the heap faster, I recently popped the intermediate shaft and with tearing down the trans:
- I found that one of the forward clutch-disk's (that closest to the reaction-plate) was apparently riding at the very edge of the associated front planetary ring-gear hub. With that, the clutch-disk's teeth were damaged (resulting in that disk not being engaged with the hub).
- I found a similar situation in the intermediate clutch-pac where that clutch closest to the front of the trans wasn't engaging the input-shaft's hub.

> Is there any reason I can't perhaps for example, machine a little off the pressure plate and slip another steel in with the reaction-plate making up for that material machined, thus moving the clutch-pac over? Better positioning the clutch/steel stack on the associated hub?

Make sense? :1tooth:

[zstroken]

You can get different size snap rings to move the reaction plate around.

Also you might be able to move the planetary backwards with a different snap wring on the end, or you might have had too much input shaft end play.

[BC847]

You can get different size snap rings to move the reaction plate around.

Also you might be able to move the planetary backwards with a different snap wring on the end, or you might have had too much input shaft end play.
Thanks for the reply. :)

- It's my understanding that the different sized snap-rings are initially intended to adjust/set the clutch-pac's clearance. A thicker snap-ring could result in too tight of a clutch pac, where as too loose could result in the clutch piston over traveling in it's bore.
- Again, it's my understanding that the different snap-rings at the planetary are initially intended to set-up/adjust the total gear-set's end-play. With too tight a snap-ring, too tight an end-play setting. Too loose without a means of taking up the slack could result is gear teeth riding where they shouldn't.

- My total end-play for the input shaft was dead in the middle of that expected by the FSM. Those thrust washers and such removed just now present with no appreciable wear.

. . . . Hmm . . . :(

[Big Blue24]

If I were you, I'd play around with machining the reaction or pressure plates like you hinted at. If you poke around on the internet and look at high performance transmission parts for these 727 based transmissions, you'll see all kinds of good ideas.

Another idea, if you don't have access or skill to do the machining, there are a lot of stock 48re parts such as reaction plates that are thinner, have machined recesses, or both. Best source I've found for used A518/A618 46rh/re, 47rh/re, 48re parts is Wittrans.com.

[mondtster]

Is there any reason I can't perhaps for example, machine a little off the pressure plate and slip another steel in with the reaction-plate making up for that material machined, thus moving the clutch-pac over? Better positioning the clutch/steel stack on the associated hub?

Sounds like a reasonable idea to try to me. Like Big Blue mentioned, you may look into the 48re stuff too, depending on what you're after.

I have to ask, do you really think you need extra clutches in the forward clutch pack at this point? It is engaged in all forward gears and people seem to break the input shaft more often than burning up the forward clutches. It might be easier to drop that pack back down to stock clutch count until the time comes when you need the extra holding capacity.

[BC847]

If I were you, I'd play around with machining the reaction or pressure plates like you hinted at. If you poke around on the internet and look at high performance transmission parts for these 727 based transmissions, you'll see all kinds of good ideas.

Another idea, if you don't have access or skill to do the machining, there are a lot of stock 48re parts such as reaction plates that are thinner, have machined recesses, or both. Best source I've found for used A518/A618 46rh/re, 47rh/re, 48re parts is Wittrans.com.
Yup, I've dug around in my parts pile and have found a thicker reaction plate and coupled with a thinner snap-ring am able to move the forward clutch-pac over a little. As such, it's a bit snug clearance wise. I'm thinking I can mill a bit off the pressure plate to give the room needed.

I have to ask, do you really think you need extra clutches in the forward clutch pack at this point? It is engaged in all forward gears and people seem to break the input shaft more often than burning up the forward clutches. It might be easier to drop that pack back down to stock clutch count until the time comes when you need the extra holding capacity.
And that's a VERY valid question (I've since learned) and I'm on the fence about taking out a disc.

I must confess I am no professional trans guy. The bulk of my work is under a tarp in the back yard. That aside, I'm not skert to build something that's impossible. When I purchased the initial parts to increase the clutch/steel count(s), I didn't know it would, in my case, be over-kill. Oh well, the parts are there, it ain't nothing but moving stuff around a little.

When I upgraded the intermediate clutch-pac, all was well till I went to twins. It would slip a little when engaging 3rd and OD during a pass. I did that a couple of times till I better dialed-in the valve-body and pressures. With that, it worked just fine. Only when I recently broke the intermediate shaft, did I find upon tear-down, that I had burned the crap out of the intermediate clutches. Who knew? Looking at things a little more has me thinking that clutch-pac is positioned OK, it just burned weird with one clutch not showing damage near the degree of the others. I've still got to cypher that one a little more.


For the sake of "Show-N-Tell", this is what the originally up-graded clutches looked like.

The forward . . .

http://i169.photobucket.com/albums/u237/BuiesCreek847/Trans%20Rebuild/RearClutchReady.jpg


The intermediate . . .

http://i169.photobucket.com/albums/u237/BuiesCreek847/Trans%20Rebuild/FrontClutchReady.jpg


I've just completed upgrading the planetarys from the OEM aluminum four pinion types (46RH), to the steel six pinion types (48RE) with a new 47RH type intermediate shaft. I even managed to go with the newer (6 tab) associated thrust washers. Got to get the end-play right with a selective snap-ring (off maybe three or four thousandths). The original front four pinion unit presented with pits in the roots of the teeth along with sloppy pinion shafts. It was due. My OEM sun-gear was presenting with some weird wear patterns in the teeth and the bushings were shot. So a new one there has cleaned up a lot of slop in the assembly.


It won't be long. :evil

Folks, I do appreciate the input and suggestions. ;)