tranny pressure too high, what resistor?

T

That Guy

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Oct 17, 2008
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as everyone knows in the 47re transmissions, once the line pressure goes past a certain point, the tranny light comes on and it runs in limp mode or something. i am not to this point yet but will be soon to hopefully get a little more out of my single disc. does anybody know the ohm rating on the resistor that is supposed to be wired in to prevent this?
 
Put in a regulator, like a VBA from Haisleys, or put in a Diode. The VBA is flawless, works very well.
 
My vote is for a Regulator, that way you can set what ever voltage you want. On a side note you can increase voltage till and gain light throttle shifts till it hang shifts then back it down a bit, at least my truck does.

Jim
 
Jim Fulmer said:
My vote is for a Regulator, that way you can set what ever voltage you want. On a side note you can increase voltage till and gain light throttle shifts till it hang shifts then back it down a bit, at least my truck does.

Jim
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DTT voltage regulator or a different brand?
 
Sounds like Dan has had good luck with his or you could call DTT. Every once in a while.....like once or twice a year I'll get a little corrosion on a connection and the voltage will drop and go into limp mode.

On the voltage deal if I have mine high like 4.7 or greater for high light throttle shifts and I have the converter locked it will sometimes hang on the 2-3 shift so I just turn it down a tad till it doesn't.

Jim
 
Jim Fulmer said:
Sounds like Dan has had good luck with his or you could call DTT. Every once in a while.....like once or twice a year I'll get a little corrosion on a connection and the voltage will drop and go into limp mode.

On the voltage deal if I have mine high like 4.7 or greater for high light throttle shifts and I have the converter locked it will sometimes hang on the 2-3 shift so I just turn it down a tad till it doesn't.

Jim
Click to expand...

i checked mine yesterday and it was 5.13, is this too high?
 
I think 5V is the limit I forget though. I thought the VBA kept it to like 4.85 or something.
 
zstroken said:
Actually 3rd gear starts.
Click to expand...

It can start second or third gear, it depends tranny condition.(this info is from DTT)

I used scanned to find ot what was my problem and I found it start with second gear.

If you start engine and start driving , transmission will chang to 2 then 3 , no overdrive and when you stop it will change to 2 and stays there.
 
AsTroSS said:
It can start second or third gear, it depends tranny condition.(this info is from DTT)

I used scanned to find ot what was my problem and I found it start with second gear.

If you start engine and start driving , transmission will chang to 2 then 3 , no overdrive and when you stop it will change to 2 and stays there.
Click to expand...


That is odd, since going to limp removes the 12V from the govenor solenoid, which means it is the same as what the computer is doing to command drive. DTT might be doing something with pressures int he VB. That is the only way I could see it. I have never seen a scanner that shows the 47RE 48RE what gear they are in. Really it is because the PCM doesn't know. All the PCM knows in govenor pressure actual, govenor pressure commanded, transmission output speed. If the convertor is locked the PCM could figure out what gear your in, assuming no slippage anywhere.

Everytime I had limp the tranny wasin third gear, you could manually pull to 2nd, and it would go to second, it would go immediately to drive if the shifter is in drive. Put the tranny in neutral pull it immediately to 1st gear and it will go to first. Once you move the shifter to second it will go to scond, and will not go back to first until you put it in neutral again. Every time I have done this I got the same results. I never did it with a DTT VB, they were stockers or Goerends.
 
At least with Snap on scanner MT2500 You can see what gear is on.


In my case, it tranny is limp home, I must shut down the engine (ignition off)and restart again, then i have again 1to3 as long I drive. If I stop then 2 stays on, no first gear. (there is no effect is ithe lever in 1,2 or D)
 
i used 630ohms worth of resistors to get my voltage to 4.5. no more 3rd gear starts:rockwoot:

cost about $2 worth of resistors. 3 -100ohm's and i 330ohm. with just the 3-100's it was at like 4.8, then i added the 330 it dropped to 4.5v.
 
looks like ill get a handful of resistors and play with it when i get my pressure turned up more. now i at least know where a good start is. THANKS!
 
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