Powerglide cooler bypass valve

[Scuzme]

Hi Guys, I'm a newbi here so first off I had better introduce myself. I am Crew chief for my Brother who runs a new Fed built to Junior Fuel regs. We basically built it because we liked the nostalgia side of things. So far we have only made around 8 passes with the last resulting in a busted transmission.
       You guys have a wealth of information here that I would love to tap into so here goes my first question.
Has anyone tried to block off the cooler bypass valve in the pump to make the cooler a full flow unit instead of just running on bypass oil. I have looked at the schematics for the Glide and I can't see why it can't be done but maybe I am missing something. 
   Looking forward to your replys.

[dusterdave173]

Dan Dishon on here will set you right when he chimes in--Great Guy
But..we all just do a loop with no cooler and get by just fine--If the trans "blew" there is something you are doing wrong in basic operation--
first--what actually happened in the trans?
Welcome--This is a great site and will get you the help you need

[Scuzme]

The transmission was bought as a new unit from a reputable builder. It is running a pro transbrake.
From the outset it seemed to be running fine and doing everything it was meant to do. Backing up, select reverse and and hold brake button in, no problems until recently when we found we could back up without holding button in. The last pass we made without using the brake and all was well until going through the 1/4 and she stepped sideways a little. the cause of this was that the band had pushed so hard on the band adjusting bolt that it pushed it through the side of the glide case. I cant tell why or what had caused it but it maybe excessive heat build up or a fault with the valve body. The result is that I am rebuilding the box with new clutch plates and fitting a new transbreak valve body, but I would like to sort out the temp problem as well.

[bikeguy307]

Was this a stock case? With some of the higher pressure valve bodies that are being made today, it's not unheard of the case failing at the adjuster. As far as blocking the bypass goes, blocking it off sending all the fluid through the cooler could over pressure the cooler, causing it to rupture. A large cooler with a fan should be more than enough, if you feel extra cooling is needed, I recommend one of the systems to cool it between rounds.

[Scuzme]

Hi Bikeguy, thanks for your reply. Yes it was a standard case. We can't run a cooler with fan as we don't have the battery capacity for that. I do think your right about an external means of cooling the oil between rounds but I also think it needs to be circulated through the torque converter from the pan, but that's a bit further down the track. I need to get some pressures and temps first.
     As far as the cooler pressures go, I have been told that is not too high for a good cooler to handle. I don't know, maybe someone can tell us. I have attached a pic of the mistress ha ha that's the cars name.

   Thanks to you all for looking and answering my questions.

[masracingtd1167]

My personal opinion is that you don't even need a cooler ! If you are hot lapping and making 10 runs a day then you might need one !

[dusterdave173]

I AGREE
If you are not lapping in a bracket race then just loop it and carry on
When we tested with trans temp converter on a bracket car the temp would climb almost 100 degrees for every second on the transbrake then drop like a rock as soon as button was released--you need that temp gauge for one race then you know from then on what is happening--Hot lapping with a brake is tough but what we usually do in these cars you have so much time between rounds that a cooler is just not needed IMO

[THE FRENCHTOWN FLYER]

I agree - in a bracket car if you go many rounds the trans will get hot enough for smoke to come out the breather. I solved it with a Hayden cooler and a small bilge fan (the type used by roundy-round racers to cool brake rotors). The fan was controlled through a relay and an inline temp sensor set to come on above 155 degrees. About as compact as a school lunchbox. It handled my 5500 stall 8 inch converter fine.

[Scuzme]

Hey thanks Guys for all your info. I will rebuild the Trans and run it and get some baseline temps and pressures and see how we go.

   Cheers and thanks for your help.