Auto Tranny Planetary Gear??

If you can find a small RWD transmission out of either a GMC vehicle or a Ford, you'll probably have a lot easier time of it. A C4 would certainly be the easiest trans to tear into, right next to a TH350/TH400.

(To get the planetaries out of a C4, you'll have to pull 7 bolts out of the bellhousing (which hold it to the front pump,) remove it, and set it aside. There's 2 ways to get the front pump out. You can either slidehammer it out, or you can drop the pan and valve body, and stick a screwdriver between the input and output shells (you'll know it when you see it, it's pretty obvious.) If you want to make it really easy, you can pull the band adjustment bolts out of the trans to let the bands go slack. (There's one on each side, the front band on a C4 is adjusted on the left front (remove the nut, then remove the bolt, ) and the rear band is on the back right,)

Once the front pump is out of the way, and you have the bands loosened (you don't REALLY have to do it, but trust me, it makes removing the clutch packs and planetary gearsets MUCH easier, ) you can remove the reverse/high clutch pack from inside the case, and assuming you removed the adjuster bolt, the front (2nd gear) band.

You can then pull the forward clutch drum out, and behind that should be the foward clutch hub / ring gear (the outermost member for a planetary, ) The actual planetary carrier is next, and past that is the sun gear/input shell.

If this set of planetaries won't do it for you, the reverse set might be a little easier to work with. You'll have the rear band to remove, of course, but the rest is just pretty much 'reach in and grab it, and pull it out.'

Hope this helps.

-LMB

Thanks Louis,

Your info will be very helpful.

I guess when I consider the size of the AT I'm remembering wrestling a C4 under and into place, by myself, without a tranny jack, on a cold wet gravel drive way, under my PU. Truck is still running on that tranny 8 years later.

I'll go back over to the salvage yard and see what is already on the ground. Maybe a core return.

Would you happen to know what the gear ratios are in different clutch packs?? or reverse.. Just a rough idea??

Thanks

Steve

Um, depending on the apply devices used, the gearsets could make different ratios:

D & 1 2.46:1 D & 2 1.46:1 D 1.00:1 R 2.20:1

First is 2,46.1, so on.

To make first gear in the C4, the one-way clutch (all the way in the back of the case) held, and the foward clutch is engaged,

Second was made with the front (intermediate) band and the foward clutch,

Third is the Reverse/high clutch and forward clutch engaged,

Reverse is Reverse/High clutch and rear band,

(it's easier if you pull the guts out of the trans and lay it out in order, then you can visualize how it makes the different ratios,

Hope this helps.

Merry Xmas

-LMB

Thanks again Louis,

However, I was hoping for a bit lower gear reduction. Something around 3:1 or lower. I don't think I have room inside my step pulley hub for a pair of these planetarys. I'll have to think this one over some more.

Steve