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View Full Version : powerglide rolling forward when applying transbrake


schultzeracing
04-13-2008, 08:09 AM
I just went to the track this past weekend, the transmission had no passes on it at all and when i applied the transbrake it rolled forward. The band adjustment is fine and the line pressure is good. Does anyone have any idea what could be causing it. I know i can run the line lock with the transbrake but i would like to stay away from doing that. thanks alot, nate

hammertime
04-13-2008, 08:44 AM
Several things can cause it, you say the band is correct where is it set ?

jmarksdragster
04-13-2008, 08:44 AM
What is your line pressure? Should be around 200 psi. Band servo should be a dual ring for best operation. Pressure leak somewhere will cause it, solenoid valve not aligned properly. What type VB, pro tree, standard or double dump?

schultzeracing
04-13-2008, 09:21 AM
The band adjustment is 3 1/2 turns out. pressure is around 220, i have a tci dual ring servo, with a tci pro tree brake. Thanks for the replies, nate

jmarksdragster
04-13-2008, 09:27 AM
3 1/2 is a tad tight for me but not your issue. Drop the pan and make sure the solenoid pushes the valve in all the way.

hammertime
04-13-2008, 10:12 AM
3 1/2 is a tad tight for me but not your issue. Drop the pan and make sure the solenoid pushes the valve in all the way.

What he said

johnracer
04-13-2008, 11:41 AM
If it rolls forward with the brake set, the reverse clutch isn't applying. If it rolls back, it's a band issue. Could be as simple as a brake solenoid failure or wrong plunger, or could be a cut seal on the reverse piston. Does it go into reverse? If reverse works, most likely a bad or wrong solenoid.....

schultzeracing
04-13-2008, 04:40 PM
I dropped the pan and the solenoid does push the valve in all the way. Also the car does go into reverse. Would the roll stop from tci be an option that could fix it? thanks for all the advice so far. Nate

johnracer
04-13-2008, 05:14 PM
Does the transbrake set after rolling forward a little, or does it not set at all?

sommersracing
04-13-2008, 05:51 PM
Does the transbrake set after rolling forward a little, or does it not set at all?


Just as Johnracer said, What is your reverse clutch pack clearance? What RPM do you stage at? Your band adjustment is fine, Reverse is not applying fast enough.

schultzeracing
04-13-2008, 06:02 PM
yes the transbrake does set the car just rolls slightly forward. I stage around 2000 rpms. And i am not exactly sure what the reverse clearance is i would have to ask the builder. thanks again for the comments

sommersracing
04-13-2008, 06:20 PM
yes the transbrake does set the car just rolls slightly forward. I stage around 2000 rpms. And i am not exactly sure what the reverse clearance is i would have to ask the builder. thanks again for the comments

Try staging at 3000 rpm. If your pump volume is low or there is too much reverse clearance, it should help. Put your pressure gauge on and apply the brake, what is your preesure readings?

us7race
04-14-2008, 02:30 AM
How much would guess it is rolling forward?

schultzeracing
04-14-2008, 02:54 AM
i tested it on the road and my father said it rolled about 4 inches.

sg1586
04-14-2008, 03:05 AM
If you didn't fill the void in the rear of the case where the fluid goes to the reverse piston it will probably fix your problem. It can be filled with eather jb weld or some companys call it quick set....

dak697
04-14-2008, 03:01 PM
I had the same problem in mine when I first started racing. 1 idle was too low another thing I tried that seemed to work was after the burn out I would drive towards the line stop and activate the brake 2 or 3 times after changing those 2 things I have never had a problem

schultzeracing
04-15-2008, 12:48 PM
i ordered a quik set from masta performance today so i will post a reply after i try it out this weekend. thanks for all the posts, nate

broywc27
04-21-2008, 05:53 PM
Any results? I've got 1 thats doing the same thing just not every time.

sg1586
04-23-2008, 11:47 AM
Any results? I've got 1 thats doing the same thing just not every time.




Did you try seting the brake with rpm up to2000rpm before setting???
Does it roll when the trans fluid is hot, or ???

What's the pressure at the servo???

broywc27
04-25-2008, 09:11 AM
Well not sure about the pressure. In the Fourth round the trans temp was at 180 (no problem rollin forward), put the blower to it and got it down to 150. The next round went in, hit the button and it rolled til I put the brakes on. Dont have to tell ya what happened (was dead late cause i was racing a car almost 2 seconds slower) anyway ran it all out and was 03 slower in et and 02 slower in 60. When coming back up the return road trans was 210 (1/8 mile track). The converter was only used about 2 or 3 weekends last year with the same engine / trans combo in my buddies digger. He thought his trans temp got a litte warm with that converter but it was never ran back to back like the other night. Were changin the converter tonight to a tried and true piece. We are also goin to check the ground on the solenoid. BTW I'm using a SLE with the rpms set about 1700. ANY IDEAS???

schultzeracing
04-28-2008, 06:15 PM
sorry for the delay in replying but yes the quik set from masta worked great! i can roll in at an idle now and it sets everytime. Recommend this for a build whether it rolls or not. thanks for all the help