Transmission Guru's Help needed

BowtiedCTD

BowtiedCTD

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Sep 10, 2006
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We have a 47RH with a 3k stall V10 converter in the Corvette(4000lbs) and it refuses to stall. Has refused to stall for the last 3 years, 5 converters(2 different manufacturers), 3 transmission tear downs and endless phone calls to manufacturer and no explanations can be reached. We had the pressure lever "wired" full forward like the manufacturer recommends. After last tear down transmission builder found a crossbleed between 2nd and 3rd in the valve body, an incorrect valve in the valve body. The last two times this trans has been assembled it has been by the trans builder. As soon as you pull the shifter into Reverse or Drive the trans goes DIRECTLY into gear and pushes against the brakes, at idle(750-800RPM). I took the "wire" off the pressure lever and it still does this. We have no clue what the phuck is causing this and it has a couple other builders completely stumped. The VB is supposed to be a constant pressure VB but yet the line pressure fluctuates at idle, at cruising rpm, and WOT. Any ideas or input would be greatly appreciated.
 
Switch valve leaking or releasing early? Have you tried to disconnect the wire harness from the valve body? Is there a pressure spike in the cooler line during a lock unlock condition? These maybe things to check.
 
These issues are at idle, no toggle switches thrown for lock up or OD. Valve body is supposed to be setup to lock converter in 2nd gear. No clue if that would cause this issue.
I can lock and unlock the converter when driving though and OD works as well.

Ill unhook the wire when I move it tomorrow and see if that helps.
 
I know this isn't the solution you want to hear, but I have had the same issue for years, down to the TV full pressure valvebody and "loose" converter, and I have found that a .032 jet of nitrous works completely, and nothing else. ;)
 
Also, the converter won't stall off idle, but c.2000rpm it is fine....sound familiar?
 
JQmile said:
I know this isn't the solution you want to hear, but I have had the same issue for years, down to the TV full pressure valvebody and "loose" converter, and I have found that a .032 jet of nitrous works completely, and nothing else. ;)
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Here is another issue, it pushes through the Corvette breaks and produces 00000000000000000000000000000 PSI of boost at launch. It wouldn't even spool a S257 with this transmission setup. Did you have the same issue? Car won't spool a 66/73/.83 until the 330 mark.
 
JQmile said:
Also, the converter won't stall off idle, but c.2000rpm it is fine....sound familiar?
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Fine as what? the trans shifts and operates properly? Yes, won't slip the trans, just no stall when trying to build boost and is very dangerous if anyone tries to move the car and people are in front of or behind the car.
 
Jason, we do have 2 10lbs bottles for nitrous but that won't solve the street issue...
 
Upgrade the breaks? Or try a pinion break. Have you tried a different transmission yet? Perhaps the valve body is warped and cross leaking?
 
Lostnwalmart said:
Upgrade the breaks? Or try a pinion break. Have you tried a different transmission yet? Perhaps the valve body is warped and cross leaking?
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They found it to be cross leaking last year when they finally checked it, it could still be honestly. Before we had this builder rebuild the trans the first time, the car stalled, but since then it hasn't stalled and the brakes shouldn't be an issue, dual piston calipers at all four corners and hydraboost. I honestly don't think Willwood's would be the fix. It will literally push the front tires without them spinning.
 
Pull a valve body out of another (known good) truck and swap it to see how she acts.
 
I have a question...

What type of cooler are you running and what size are the lines?

On an RH, a restricted (not blocked, but partially restricted) will cause a partial lock up apply.

The easiest way to test this would be to go from Park, directly to Drive, without stopping in Reverse or Neutral. If it kills or almost kills the motor, there's your answer.

Another test would be to simply loop the tranny lines at the case - bypass the cooling system completely.
 
Hayden 3 or 4 qt cooler with 1/2" lines. I'll have to try that test tonight after work.
 
TheWanderer said:
I have a question...

What type of cooler are you running and what size are the lines?

On an RH, a restricted (not blocked, but partially restricted) will cause a partial lock up apply.

The easiest way to test this would be to go from Park, directly to Drive, without stopping in Reverse or Neutral. If it kills or almost kills the motor, there's your answer.
Another test would be to simply loop the tranny lines at the case - bypass the cooling system completely.
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I did this just today and there's no change, it doesn't kill the engine, just lugs it down and goes like a mofo. It would have to be one heck of a restriction. The trans cooler is just ahead of the radiator, and has 1/2" passages through out. We just flushed the lines and cooler before reassembling the car this past week. We might by pass it just to see. You never know.

IMG_1090.jpg

IMG_1089.jpg
 
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Lostnwalmart said:
Upgrade the breaks? Or try a pinion brake. Have you tried a different transmission yet? Perhaps the valve body is warped and cross leaking?
Click to expand...

It has hydraboost brakes with 4 piston calipers on all 4 corners. It has brakes, LOL My thing is, the trans shouldn't be lugging the engine that hard with a 3k stall converter at idle. The car shouldn't want to even try to start moving until above 2k. This thing was like that 3 years ago before the TP cable came off and we hurt the trans. Trans was sent off and ever since, no stall at all. We just ordered a VB from Darren so we'll have to see if it fixes it.
 
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Sucks you are still having problems with this, doesn't the trans builder test the valvebody on his stand before sending it out?
 
GOT-Torque said:
Sucks you are still having problems with this, doesn't the trans builder test the valvebody on his stand before sending it out?
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They said they did. But IDK if it was done. This trans and converter were supposed to be dyno'd together too, and they weren't. That's a touchy deal. :bang
 
GOT-Torque said:
Sucks you are still having problems with this, doesn't the trans builder test the valvebody on his stand before sending it out?
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I was uner the impression this builder test everything before sending it out.
 
SHughes said:
I'm stumped. Though I'm not a guru either.
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Me too. I wonder if NHRA will allow a hand operated clutch? A NV4500 and a triple disc sound pretty tempting. LOL I see 47rh and re's stalling at every diesel event we used to go to. But I can't get this sob to stall more than 1400rpms. Real sweet. *bdh*
 
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