Ok so I know this is somewhat unorthodox but I have a 904 in my dirt track car with a Direct drive so no converter. It hits so hard when i drop it in gear that I think I'm going to break something. I will be racing in second gear so I only need first and reverse to get moving or to back out of a on track situation. So I was wondering if I loosened up the rear band apply if it would soften the gear engagement. My only other option that I know of is to put a valve on the pump output to bleed off pressure until i get moveing. I have done that before but I kind of want to keep this incogneto because it isnt exactly legal in this class. the GM guys get away with it with a powerglide and a custom valvebody that bleeds off pressure.
Low reverse band adjustment?
- Thread starter mod5v
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More slack in the band might make your problem worse. It sounds like you need to reduce pressure somehow. Is your accumulator functioning? Some shift kits eliminate it with a spacer, if you have done that you might want to put the spring back in. Have you put a guage on it? You might simply need to back off the pressure some
TrailBeast
AKA Mopars4us on Youtube
That is possible, because most people think a loose band makes a softer shift and it's actually the other way around.
He could also put a restrictor plug in the rear servo apply port, as that would slow the fluid but still allow the pressure to stay the same.
Very first thing I would try would be to tighten up on the rear band.
If you Google it there is a procedure to get it as tight as safely possible by turning the driveline.
Humm so Either tighten the band untill it can just spin when not applied and or resrtict the fluid port to slow it down. the restriction sounds like the best first option. do you think I could do that with the trans in the car. I have a lift so getting under there is no problem. I have a spare trany so I will pull the pan valve body and the servo piston and look at it. Thanks for each and every suggestion.
famous bob
mopar misfit
looser convertor ??
TrailBeast
AKA Mopars4us on Youtube
Exactly, but you will have to get the valve body off for the restrictor insert in the rear servo port.
I'd go 1/8 inch on the orifice. (basically, you are just installing a jet like carbs use to control fuel flow but for the rear servo speed)
Total holding pressure will not change.
So I'm looking at the spare tranny and there is a plug in that rear servo. Could I run a line from that thru a ball valve and return it back to the pan. Close the valve to go and open it to act as a pressure dump.
The other thing I need to know is will that work for both forward and reverse. I'm just not sure how that band works exactly.
The other thing I need to know is will that work for both forward and reverse. I'm just not sure how that band works exactly.
The pressure dump would work, but it will be obvious your trans if modified. I have seen powerglides set up like that for roundy round racing. Reducing the pressure and/or a restrictor in the feed line will help, but you are going to have a pretty harsh engagement no matter what. The little band is applied in manual low and reverse, the larger band is for second. You should get online or look at a book and study how the torqueflite works, it is pretty interesting stuff.
FYI the little mod I tried to bleed the pressure of the rear band servo did'nt work so I put a torque converter back in the car for now. I will modify the pump housing on my spare and get that ready to go. I know at one time there was a valvebody modification done by one of the mopar tranny gurus that would bleed pressure in low and reverse but I have lost that information. In esence what he did was bleed off pump pressure so that the clutches wouldnt engage at idle but when u gave it some gas the extra volume would be enough to engage the clutch drum and away u would go.
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