? about welded forward drum

[JDSfastGN]

In the process of trying to get my friends directs to last i really want to dual feed the clutches but he is kinda on a small budget. The drum is not exactly stock but it is not a billet unit. It appears to be back cut and welded behind the splines. I know this is not a ? that can be answered accuratly but should i try and see if it will last with them dual fed? Does anybody have results using a similar unit? Since the tranny was done by a local houston guy many years ago im assuming its an older PMAC (Mike Kurts) design before the billet parts were available but really have no idea. Thanks guys.

 

[bison]

I dont reccomend dual feeding with anything other than a billet shaft drum. If your friend wants to save some aggravation he should really consider the billet drum. Ive heard of factory heat treated ones living but i dont want to test this for myself. GM's QC on materials for these was horrible. I just finished inspecting the trans and upgrading the input, ring gear, and forward drum in Jim Rome's (JRSGN) old transmission that i bought from him. The OD planet was already upgraded :biggrin: . It was run with the directs dual fed in a 135mph car and the forward drum lasted. Otto did well with this one but im afraid of breaking the parts i mentioned above. If you want to buy the drum that was in that transmission shoot me a reasonable offer and its yours. On another note ive never seen the directs last in a sub 11 second car without the dual feed. They may last awhile but not anywhere near as long as when dual fed. Be sure to get a new GM seperator plate. You will not be able to use yours if the 3rd accumulator hole has been plugged. Good luck

 

[blackplague]

I dont reccomend dual feeding with anything other than a billet shaft drum. If your friend wants to save some aggravation he should really consider the billet drum. Ive heard of factory heat treated ones living but i dont want to test this for myself. GM's QC on materials for these was horrible. I just finished inspecting the trans and upgrading the input, ring gear, and forward drum in Jim Rome's (JRSGN) old transmission that i bought from him. The OD planet was already upgraded :biggrin: . It was run with the directs dual fed in a 135mph car and the forward drum lasted. Otto did well with this one but im afraid of breaking the parts i mentioned above. If you want to buy the drum that was in that transmission shoot me a reasonable offer and its yours. On another note ive never seen the directs last in a sub 11 second car without the dual feed. They may last awhile but not anywhere near as long as when dual fed. Be sure to get a new GM seperator plate. You will not be able to use yours if the 3rd accumulator hole has been plugged. Good luck

You can dual feed and still have the 3rd accum hole plugged { the ck ball hole}. You just have to drill the orifice next to the ck ball hole.

 

[bison]

You can dual feed and still have the 3rd accum hole plugged { the ck ball hole}. You just have to drill the orifice next to the ck ball hole.

Yeah you could do that if you want. Just make sure you prick punch and drill in the right spot :biggrin:

 

[jakeshoe]

Yeah you could do that if you want. Just make sure you prick punch and drill in the right spot :biggrin:

The holes is already there, you just have to drill it larger.

 

[Lee Thompson]

interesting post

Just back from the track and this is the second time this season that I am getting 25-28 bottom 10 second runs with out dual feeding. Looks like I will have to have the billet drum and dual feed. Last time just a couple direct frictions were starting to burn. Sure I will find the same thing this time. Just starting to develope a 2-3 flair. I did weld the forward shaft--I was wondering if I should try dual feeding with it.

 

[brian]

JDSfastGN,
To help with your question...
IMO... I think it depends more on the converter you are using, rather than the type of drum. At least with my experience. lf it is a 12in converter, it may not make it around the block. If a 10in or similar, it will probably be OK for a while until it gets pushed hard.


I constantly see all these recommendations flying around for dual feeding and I scratch my head...why? Does anyone think to change the way you approach this area in the build? It seems as if we are looking for a band aid for the issue. Dual feeding may help, but there is no magic pill. They still may not hold. Only thing is to re-evaluate the process "we" are using. I have not personally seen the need to dual feed.
Guess I`m lucky.

Lee,
It is very refrehing to see someone that is NOT dual feeding. You made my night.
As a side note to you, I may be doing some more of those servos soon if you still want one.

Thanks, Brian

 

[JDSfastGN]

JDSfastGN,
To help with your question...
IMO... I think it depends more on the converter you are using, rather than the type of drum. At least with my experience. lf it is a 12in converter, it may not make it around the block. If a 10in or similar, it will probably be OK for a while until it gets pushed hard.


I constantly see all these recommendations flying around for dual feeding and I scratch my head...why? Does anyone think to change the way you approach this area in the build? It seems as if we are looking for a band aid for the issue. Dual feeding may help, but there is no magic pill. They still may not hold. Only thing is to re-evaluate the process "we" are using. I have not personally seen the need to dual feed.
Guess I`m lucky.

Lee,
It is very refrehing to see someone that is NOT dual feeding. You made my night.
As a side note to you, I may be doing some more of those servos soon if you still want one.

Thanks, Brian

Brian, i respect your opinion and have heard nothing but good things about your trannys. What exactly would you do different to not have to dual feed? My directs used to do ok....but would be worn a bit and began to slightly flare after a few months of 11 sec passes. After dual feeding i have not had any problems what so ever with probably 60 track passes over the past year or so as well as many many hard street miles. Without dual feeding in the past i have used an art carr shift kit and a CK, and neither were firm enough at the 2-3 for my liking until i dual fed. I've used both reds and blues in the directs usually around .040-.045. I don't want to steal your secrets but im just curious what special mods you do to achieve a solid 2-3 shift in a 450+hp car. special plate mods? extra clutches? kolenes? servo mods? etc.... just curious as i would love to get my friends tranny to live. The main problem is i didn't initially build it and it has extensive old school valvebody/servo/accumulator mods that i am probably gonna try to reverse. Thanks for all the replies guys

 

[jakeshoe]

I don't see why you would NOT dual feed for a hi-perf application.

First,
If it's a solid 11 secondc or faster, it needs the good drum period, with or without dual feed IMO. Why risk a drum failure to save $400. The tow bill may almsot that much, much less overhaul parts and fluid, time.

Second,
Dual feeding is not a new approach, it is used on TH350's TH400's, and others very commonly. It is basically considered mandatory on these with any real power, otherwise the direct clutches life is shorter. The TH350 and 400 have larger friction area too...
Basic hydraulic theory makes this a simple decision IMO. More apply area= more holding for a given pressure.
Sure we can jack the pressure way up, and try to not dual feed, but this creates other issues.

Dual feeding is a simple and basically free mod. It isn't a band-aid. It is a proven method.

 

[Lee Thompson]

?

I don't have trouble with the directs HOLDING (no slippage once they engage) It is the flair on the 1-2 shift that causes problems. I run 280 line pressure and the clearances are on the tight side. I wonder if it is the clearances opening up after so many shifts that the flair developes.

I wouldn't exactly call it a free mod since you have to buy a $400 drum.

 

[83hurstguy]

If it's a solid 11 secondc or faster, it needs the good drum period, with or without dual feed IMO. Why risk a drum failure to save $400. The tow bill may almsot that much, much less overhaul parts and fluid, time.

Brian DOES use a good drum in his trannies... and when he needs to, a billet drum... :wink:

 

[Lee Thompson]

Brian

Would it be asking to much to tell us how you setup your direct clutches or how much line pressure you like? If not ignore this post and I will understand.
BTW, I have some machined aluminum WIDE apply rings to replace the stock narrow one for forward and direct. Also shorted to allow more room for extra clutches.

 

[JDSfastGN]

I don't see why you would NOT dual feed for a hi-perf application.

First,
If it's a solid 11 secondc or faster, it needs the good drum period, with or without dual feed IMO. Why risk a drum failure to save $400. The tow bill may almsot that much, much less overhaul parts and fluid, time.

Second,
Dual feeding is not a new approach, it is used on TH350's TH400's, and others very commonly. It is basically considered mandatory on these with any real power, otherwise the direct clutches life is shorter. The TH350 and 400 have larger friction area too...
Basic hydraulic theory makes this a simple decision IMO. More apply area= more holding for a given pressure.
Sure we can jack the pressure way up, and try to not dual feed, but this creates other issues.

Dual feeding is a simple and basically free mod. It isn't a band-aid. It is a proven method.

this is what i tend to believe..... every car ive dual fed i have had great results with so far. IMO its no more a band aid than higher line pressure or a wider band.

 

[JDSfastGN]

Would it be asking to much to tell us how you setup your direct clutches or how much line pressure you like? If not ignore this post and I will understand.
BTW, I have some machined aluminum WIDE apply rings to replace the stock narrow one for forward and direct. Also shorted to allow more room for extra clutches.

Do you still offer these Lee? Im using one in my tranny and I really liked it. Was able to fit an extra direct clutch only using one thinner steel in the process thanks again.

 

[Lee Thompson]

Yes

I have a few left and may make some more--let me know.

 

[WE4]

We make the direct piston

Looks something like this? LOL
We have been making these for some time. They are not fun to make but I have for people who ask. They do work by not allowing the flimsy apply rings to deflect the steel. (Apply more in the center only)
Here are some pics and they can be ordered but they are not on our site.
If anybody should want some , contact us.

Bruce
WE4
www.PTSXTREME.com

 

[Lee Thompson]

Bruce, fwiw

Did not copy these off you. Actually copied them off GM as they have an aluminum apply ring in some of the forward units. Did not know you offered them or have never seen them for sale by anyone. The ones I have are not exactly like your but the principle is the same.

 

[WE4]

Lololol

Did not copy these off you. Actually copied them off GM as they have an aluminum apply ring in some of the forward units. Did not know you offered them or have never seen them for sale by anyone. The ones I have are not exactly like your but the principle is the same.

Got a guilty conscience? LOL :biggrin:

I was just saying that I make these and have for awhile. I applaud you thinking about it and appling it to work!!
Yes the forward drum pistons from 2/88 to the end of the run in 1990, they had what they called a "Constant bleed system" so that Grandma would not complain on apply from park to drive cold. It is supposed to squish the wavey to close the bleed holes to cushion apply. However, to make the forward piston work in the direct, you must do precision machining and you ruin the forward piston, so what. It does take time as you well know now.

Like I said, I just wanted people to know they can be made and are being made but remember, everything comes with a price. For you, Lee, it is time, for me it is time and money.
LOL

Keep up the good inventing, it shows we are all thinking......


Bruce
WE4
www.PTSXTREME.com

 

[laz]

Hey i had done 200 that have lasted over 100 low ten second passes without dual feeding .I have pretty good look just using a shift kit on a stock trans into the tens nothing fancy .The thing is all the fast cars where non lock up the lock up ones ate clutches right away jmho .

 

[Ttype6]

I tried dual feeding and got nothing but bad results. There's no doubt that more apply area equals more holding power. No one seems to understand that this is more of a problem than a solution. There is a timing issue with third gear,meaning that two things have to happen in relationship to one another. The direct clutches have to apply at the same time the band is released. If the band releases before the clutches apply,you get a flair up. If the clutches apply before the band releases,you get a bind up. If these two events happen at the same time the clutches last forever. If these two events aren't timed properly the direct clutches and band take a beating. When you dual feed,you screw up the timing of these two events. Because you have more apply area,you have more force holding the clutches at any given pressure. What this means is the direct clutches start to hold faster than they used to. The band,however,releases at the same rate. When the trans shifts into third at light throttle it will feel like someone stepped on the brake for a half of a second. I don't believe other dual feeders haven't experienced this. I know they don't talk about it. Since you have more holding force at any given pressure the direct clutches will hold on longer during a 3-2 coastdown,but the band will apply at the same rate as it used to.This creates an unacceptable bind up during a 3-2 coast down. The third thing that happens when dual feeding is you get a harsh apply at full throttle when shifting into third gear. It feals like someone is hitting you in the ass with a sledge hammer. This is what takes out the stock drum. Why doesn't anyone talk about this? Again,when these two events happen at the same time,in relationship to one another the clutches and band are spared.The question is how do we coordinate these two events. I've seen it written many times that you can drill the third accumilator hole next to the checkball in the sepperator plate to speed up the nocking off of the band during a 2-3 upshift. Wrong. This hole is there to slow down the oil leaving the third gear accumillator during a 3-2 downshift If you drill this hole bigger,oil will leave the third accumillator to fast during a 3-2 downshift. This will allow the band to apply before the direct clutches can release during a 3-2 downshift causing a bind up. You can change the rate at wich the band gets nocked off during a 2-3 up shift by using a stronger or weaker servo return spring.The stronger the spring the faster the band gets nocked off during a 2-3 up shift.The G.N. return spring is the strongest factory spring for the 2004r.This is the spring to use. Never use a weaker spring. The only way to correct a 2-3 up shift timing problem is to set the direct clutch clearances at a very specific distance.You need to find a guy who is very anal about machining. That guy is bruce at P.T.S.Extreme. I recommend That you always buy a direct drum from bruce,because he turns it on a lathe making the band apply surface truly flat. This makes the 1-2 upshift as good as it gets. When you order the drum ,have him load it with clutches. He'll set the clearence right on and this will correct 2-3 upshift timing.This will also correct that 3-2 coast down clunk. I,m sick and tired of reading about simmilar transmission horor stories only to find out at the end of the story that the problem was solved by buing someones transmission. The guy learns nothing obout the cure and neither do we. After 15 years of trying to get a trans to shift into third without making me sick to my stomach, these are the very simple and specific things that worked for me. It's because of Bruce. Buy a direct drum from him. When you open the box and see it for the first time,you might be tempted to put it on the mantel in the living room. It's truely a work of art.