48re forward clutches wiped out for the 3RD time

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davem3261

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So I rebuilt my trans about 2000 miles ago. I pulled the trans out because I am ditching the suncoast valve body for a goerend. Dave wanted me to change my lever to a 3.8. I wanted to check it out and see if everything was ok and it is not. I used alto clutches and all the thin backing backing plates that PATC sells to fit the extra clutch in forward, direct and OD brake. There was no wear on any of the clutches except for the forward clutches. I have been getting 10k out of a trans before I kill the forward clucthes. The 2 outer clutches seem to be ok but the 3 in the center are getting burned. I did realize that I have to shim the drum out to get better contact on the forward gear ring. The 5th clutch is on the very edge. I couldn't tell that the past 2 times because all of them were completely warped last time. I had .032 clearance when I put it together.
 
The only thing I can think of is that there is not enough line pressure to hold in forward. I hope the goerend VB is a fix for this problem. Even if 4 of the 5 clutches were grabbing it should hold at my power level. I haven't towed or raced it since the last time i rebuilt it
 

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What he said above. You just need to use a rubber tipped air nozzle,also it has Zero to do with the Suncoast valve body design!!!!!
 
So I have to find which hole in the case goes to the forward clutch put air to it to see if it has a leak? No i didn't put a pressure gauge on it after I had it in. I bought a used trans pressure gauge so I will be checking it after it is together. Is there a port on the trans where i can check the forward clutch pressure? I wanted a new VB anyways. The suncoast has always shifted funny after sending it back a couple of times for them to make changes.
 
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I built the trans. The forward clutches lasted 40k the first time and 10k each time after that. I am going to try to get ahold of dave on Monday to see what he thinks about it.
 
davem3261 said:
I built the trans. The forward clutches lasted 40k the first time and 10k each time after that. I am going to try to get ahold of dave on Monday to see what he thinks about it.
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Make sure your input shaft hub is not cracked! I have seen them with hairline cracks and when the piston applies it will bleed out pressure. FWD is a pretty stout gear to consistently burn them out.

Also, as it was mentioned above, pressure test the fwd gear, to make sure you did not cut the seal.
 
I always had problems burning them before I started using Goerends valve bodies. I tore into my tranny a few weeks ago to check them out after 200+ passes. They look brand new still. I saved them just to show people. I have a fwd clutch pack out of another big name tranny with 14k miles on it in a 500hp daily driver and it is toast. Along with a lot of other parts.
 
Blacksdieselhp said:
I always had problems burning them before I started using Goerends valve bodies. I tore into my tranny a few weeks ago to check them out after 200+ passes. They look brand new still. I saved them just to show people. I have a fwd clutch pack out of another big name tranny with 14k miles on it in a 500hp daily driver and it is toast. Along with a lot of other parts.
Click to expand...

Daves VB's are the best hands down!!

All we EVER use, unless someone specifically asks for different.

Thanks
Les
 
It could be a few things.... Have you pulled your vb apart and cleaned it? Have you changed the foward aply piston lip seals? I'm not a fan of red alto clutches. You can ask anyone that knows me how many trans I have been through. The Raybesto High energys seem to be the best imo.
 
Are you running a double belleville spring, or just a single stock one?

Are the burned up frictions in the middle next to warped steels? What do the steels look like as far as wear and color?

Are you sure the forward clutches are all splined on the forward ring gear? The ring gear is pretty narrow, just barely wide enough to engage (5) fricitons if the pack is shimmed perfectly. It's possible that the two outer clutches are not splined into the forward ring gear and therefore only the center 3 clutches are wearing.
 
The steels are not warped. The last clutch was on the very edge of the forward ring gear. I have different size spacers so I can fix that. So 4 were engaging. The alto clutches are not the problem. Every time I tear it down I mic all of the frictions and they have no wear or .001 of wear after 70k at 500 hp. What is a belleville spring?
 
No I am running the stock single belleville spring. Dave at goerend says my truck came with a gas 48re. The accumulator piston had 2 springs where there should be one and it had a 4 pinion OD planatary. I bought the truck new, I guess the factory goofed when they built my truck
 
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