Dual Feeding direct drum, casuing forward to snap..

[jakeshoe]

Hey guys,
Why exactly does dual feeding usually cause forward drum failure?

Directs apply too fast?

Is it something that can be calibrated to lessen the chances of occuring or?

I know the real solution is to buy a billet drum..
I had one and it is sitting in some insurance companies impound lot waiting on a settlement for the last 6 months... In a fresh 200-4R with GN VB, billet servo, etc..
$1400 in parts sitting where I cannot get it because the case is busted and the insurance doesn;t want to pay my labor to fix it, or for the truck..
Anyway off the rant.

Any tech tips?

 

[chris718]

there really is no way around it,but you can try it with a stock seperate plate undrilled.the directs apply before the band releases and the material gm used was insufficient.

 

[jakeshoe]

Thanks Again Chris,
It is nice to have someone give REAL tech help.

I tried to call you Friday, I'll call you later this week.
I need to get one of the 200 servos. I looked around the local wrecking yard and did not find either the 112 or 111 servos even though they had prolly 8 old 200 trans.

I do have the good GN servo I may use for a bit.

I built up the internals on the 200 today, using stock stuff mostly.
I added a clutch to the OD pack, installed the wide Alto band, a metal sun shell to low support thrust washer (discovered a very easy interchange )

Don't even ask how I machined the OD piston LOL

I did not dual feed the directs.

What is the deal with the 13 vane pump kits. I've heard they are failure prone, they crack..
That is what happened to this core. Everything inside was new. Probably could have re-used all the clutches.

The pump body was not hurt though fortunately, so I just need to replace all the internals and install the pump, VB, Servo.

Any tips on spacer plate hole sizes?
I have a new GN spacer plate. The one on this core had some holes drilled.

I'm gonna build this one cheap, and see how well it holds up for giggles.

I'll call you about the servo and maybe even a VB kit, some other misc stuff I need.

Thanks.

 

[Morkai]

Originally posted by jakeshoe
Thanks Again Chris,
It is nice to have someone give REAL tech help.

I tried to call you Friday, I'll call you later this week.
I need to get one of the 200 servos. I looked around the local wrecking yard and did not find either the 112 or 111 servos even though they had prolly 8 old 200 trans.

I do have the good GN servo I may use for a bit.

I'm having good luck with the large GN servo and alto wide band.

I built up the internals on the 200 today, using stock stuff mostly.
I added a clutch to the OD pack, installed the wide Alto band, a metal sun shell to low support thrust washer (discovered a very easy interchange )

Don't even ask how I machined the OD piston LOL

Can any good machine shop do it? I hate to pay $50+ when I can get it machined and buy one extra friction.

I did not dual feed the directs.

How many clutches are you running in the direct, any extra over stock? I'm in a simular situation I don't have the billet drum and didn't dual feed because of it. Now I think I'm starting to loose my directs again. I'm thinking of just trying the 2 extra clutches since I can't yet afford the drum yet.

What is the deal with the 13 vane pump kits. I've heard they are failure prone, they crack..
That is what happened to this core. Everything inside was new. Probably could have re-used all the clutches.

The pump body was not hurt though fortunately, so I just need to replace all the internals and install the pump, VB, Servo.

Any tips on spacer plate hole sizes?
I have a new GN spacer plate. The one on this core had some holes drilled.

I'm gonna build this one cheap, and see how well it holds up for giggles.

I'll call you about the servo and maybe even a VB kit, some other misc stuff I need.

Thanks.

 

[jakeshoe]

Morkai,
I'm using stock direct pack, stock tan type clutches even.

IMO dual feeding is almost a necessity on most GM trans. ALL the shift kits for a Th350 do this mod, TransGo kits do it on a Th400, and when building either unit as a race unit, it is a must do deal, they can both be done internally as well.

You can HELP the directs by upping line pressure, good calibration, but dual feeding is the REAL answer. But as stated the drum is likely to snap.
I don't want to deal with a snapped drum at the moment and can deal with burnt up frictions later on (when i get my real unit back with the billet stuff..)

I'm actually just after the OD and want to test a couple of things on the 200-4r's.

Plus I have "other" plans for my TH400

I will do some testing with the GN servo and the 200 piece..
I need to find the 200 servo. I know where a dozen of those trans are at so maybe have to go scouring again...

Since you HAD to ASK..
Last time I built one of these I used a lathe to cut the OD piston.
It was actually a bitch. It kept wanting to chatter, even with a sliencer band, and would work loose on the lathe.
SO....
this time I took a grinder after the damn thing.
I cut .070" off, measuring as I went to try and stay cocentric all the way around...
I was able to stay within .007".
I thne took the piston, and "flat sanded" it on the driveway
This knocked off the high spots, made it all even.
Then I flat sanded using some 100 grit paper and a piece of smooth tile.
It came out perfect..

I'm a certified machinist, but don't have a machine shop at my disposal currently and I cringed at the thought, but it came out so good that I won't hesitate to do it again...

 

[Morkai]

I'm running reds throughout, with .040" on the directs. I think next time I might try the 2 extra clutches and koleans, plus an extra in the OD. I'm gonna verify I have enough line pressure though.

I think I'm starting to get 2-3 flair at WOT again. Anything lower than WOT it shifts good. However, I may have hurt it early on, not long after I built it I left the TV unhooked one day. Drove it and not easy I might add, trying to figure out wtf was wrong. It only hit me after it was too late and I know I did some damage. That was a while back...

Humm, I might just have to try that on the OD piston, I think I have one laying around in the shop.

When you're poor like me, you gotta save where ya can....heh

 

[87GN_70GS]

I just used one of those big belt sanders (like 2 feet wide) that a head machine shop uses to resurface a head.

 

[chris718]

jake ,i forgot to call.give me your number and we will take care of you on the drum.

 

[Morkai]

DIRECT CLUTCH DRUM POWER PACK

Chris, I have a question, I was going to do the 8 directs, and at first I was wondering if you sold it with less clutches/steels since I would already have most of them.

Now I'm really puzzled on how it's even done! Correct me if I'm wrong, but based on my measurements, I have right at 1.240" of space in my direct leaving .040" clearance (including BP). Now even if you use .010" under steels, 8 frictions at ~.080" and 8 steels at the same addes up to 1.280" and that's not even adding in a backing plate.

How does your power pack do that with only a special backing plate?? Enlighten me.

 

[jakeshoe]

Morkai,
I think the Alto frictions are thinner than .080"... I could measure one tomorrow..

 

[Morkai]

Friction

The Alto red I have isn't, well maybe .079"

Do they make a thinner friction? That might work... Even if you had .070" frictions it would only leave about .040 for the backing plate. The only way I could see it working is with .070" frictions and steels, then about .120" BP.

Maybe my #'s are wrong, but I don't think so. It's just killing me know know how it's done.

I think I figured if I went with .080 steels and .120" BP I could slip one extra in the pack. I'm just wondering if the extra friction is worth thinning it all out.

Can you get koleen steels undersized? I have 6 std size ones I have never used yet. I was thinking of trying them this go around.