Couple of forward drum questions

[Mike T]

Tearing down to inspect after pump failure. First question is will the slight notches on the forward where the direct friction's ride be a problem. And second I found the inner piston seal to have a chunk missing where it seals on the shaft. Will replace it but I'm very curious what symptoms this would have show in the tranny operation.

 

[SCOOBY DOO]

Mike...the weak link in these cars is the transmission. Buy every billet part you can afford. I'm fairly certain I have more money in my transmission that what my house is worth.

 

[Mike T]

Photo doesn't show but at least it's a billet shafted drum. See now why billet pistons would be desirable .....stock apply surface is very thin

 

[INEEDAGN]

I would consider the wear to be acceptable especially since it's a billet drum. Not like you're going to throw it away. Pretty sure I've bought new billet drums with almost that much wear in them.

The seal would cause a circuit leak in forward but as long as forward isn't burnt, it obviously didn't hurt anything. Probably helped soften the apply lol.

 

[INEEDAGN]

Billet piston or apply ring is a good idea in direct, unneeded in forward unless you like spending money for the sake of having every billet part you can. I've used a billet piston in fwd one time when I had a billet drum without the bleeder ball capsule in it and didn't trust the stock aluminum piston that came in those drums. People have posted that the steel piston still works fine in that situation but I used the billet one anyway. The feed/bleed aluminum piston setup could be tailored for a smoother "garage shift" than the steel piston, at least in theory.

 

[Mike T]

The seal would cause a circuit leak in forward but as long as forward isn't burnt, it obviously didn't hurt anything.

Well once again you obviously know your stuff The clutches are burnt, couldn't believe it because it shift and drove so well.
The only complaints were a slightly slow 2-3 (only at very low throttle angles) and in neutral it seemed to pull a little when revved (would guess tight clutch pack).

The seal must have caught the snap ring groove during installation because the missing chunk was still in the clutch pack.

 

[INEEDAGN]

That particular seal can be a bitch to install if you don't have the tool. It would be easy to screw it up but should have been caught with an air check before the drum went in the case. Forward may have been burnt for a long time especially if it crept in neutral. Since it doesn't shift under load it can actually be pretty f'ed up and still work under normal conditions.

Well once again you obviously know your stuff

I'm just a hobbyist builder and don't claim to know everything about them, last few years it's almost become an obsession though. Learned a lot from Dave, Lonnie, Chris, and Bruce etc. and their willingness to share knowledge is huge in this community. These transmissions have went from being the weak orphan to a great choice for many applications thanks to these people and others like them.

 

[Mike T]

Learned a lot from Dave, Lonnie, Chris, and Bruce etc. and their willingness to share knowledge is huge in this community.

Yes I've read a lot of old post haven't seen much posted by any of them lately though.

 

[Steve V]

INEEDAGN covered just about all of it. With a billet drum one thing to lookout for is the billet shaft being welded in crooked. Easiest way to check it put it in a lathe and verify. The best source for billet drums is Scott Mclay. I have seen issues with others billet drums, I've spent a lot of time with RC and built trannys with him he's shared a lot of knowledge along the way.

The only billet part that is really mandatory is the drum IMO. That's for a real fast car that gets good traction and/or lockup the converter at WOT and any dula fed application. Believe it or not I recently had dual fed unit come through my shop that was done on a stock drum. It was a name brand builder too. One of the reasons I learned to build my own years ago.

 

[Mike T]

Was told of the billet drum wobble a little while ago, put mine in the lathe this morning and it's out about .050.

 

[Steve V]

Was told of the billet drum wobble a little while ago, put mine in the lathe this morning and it's out about .050.

So that means your direct drum is wobbling .050 the band is grabbing it for 2nd gear. Not ideal situation.

 

[bpman1234]

would love to try and rebuid one my self I have a 200r4 that came out of my 85 442 olds has a BR3 valve body.where woul be the best place to get all you need ?

 

[Steve V]

would love to try and rebuid one my self I have a 200r4 that came out of my 85 442 olds has a BR3 valve body.where woul be the best place to get all you need ?

I don't use any commerically available kit. I piece my own together. Send me a pm and I can help you out with parts and a build recipe if you want.

 

[bpman1234]

OK thanks.

 

[INEEDAGN]

Interesting on the drum runout. I've never checked it. I did get one once that was oval shaped apparently from being dropped. My pet peeve is the burr in the sealing ring grooves where they cut it down and don't deburr the edge. Also seen large chips wedged in the lube holes. Trust the new parts less than the used ones lol.

 

[Steve V]

Interesting on the drum runout. I've never checked it. I did get one once that was oval shaped apparently from being dropped. My pet peeve is the burr in the sealing ring grooves where they cut it down and don't deburr the edge. Also seen large chips wedged in the lube holes. Trust the new parts less than the used ones lol.


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BTW I just update the thread with spring pressures you wanted.

 

[INEEDAGN]

....

 

[Steve V]

I'll send you a pm later if I don't forget.

It's all good.

 

[Mike T]

Spun a stock drum in the lathe and it wasn't perfect but much better than the billet shafted drum.

On the back side of the billet shaft 1 of the 2 holes is brazed shut, what's the reason for that?

 

[INEEDAGN]

Spun a stock drum in the lathe and it wasn't perfect but much better than the billet shafted drum.

On the back side of the billet shaft 1 of the 2 holes is brazed shut, what's the reason for that?

They have to drill the passage from the Teflon rings down to the angled passage behind the piston. Then they have to shut the massive circuit leak they created by drilling it through. It's just the easiest/most cost effective way and ensures there's no plug to fall out. Factory is done this way just plugged with a cup plug.