Trans Brake issue....

December 21, 2021, 05:32 AM

fuzzy dice

I apologize if this runs long...for two years now I have been fighting an issue with my trans brake...what happens is I let go of the button and the car does not move...then it launches by itself giving me an awful light usually between .175 and .250...it acts exactly like I am using a delay box but I don't even have one in the car...

We have changed solenoids twice, new Biondo mushroom button...pulled the tranny and had it gone through completely...had the car completely re-wired professionally, every inch of wire is new...

It is an FTI glide and 8" converter...I put in a new aluminum valve body two months ago...every ground has been checked and re-checked...this problem shows up intermittently...sometimes week to week and sometimes 6 months apart...it happened at Brdenton last week so I left and then again at Palm Beach 3 days later...

Nobody seems to be able to find this glitch so I am asking for this boards help...the only part we have not focused in on is the MSD 6AL2...thanks in advance...

December 21, 2021, 06:05 AM

Footloose

Have you tried scotch brighting the solenoid shaft? They can get a tiny burr and it can do just what your talking about.

December 21, 2021, 06:14 AM

Jerry Kathe

I’m not sure on the FTI valve body if it’s a double dump or not, kinda guessing it is. (call FTI/Greg and find out and also ask their opinion on this) What case are you using and how was it prepared in the reverse clutch area? Are you using the adjustable fluid release orifice if equipped? Does it come out of reverse ok? Other than RPM control, what else is tied into the positive side of the brake solenoid?
Any notable correlation of cold/hot transmission temperatures?

December 21, 2021, 08:44 AM

329L

Did you have the issue before you changed the valvebody?

December 21, 2021, 09:12 AM

rusty

line lock?????

December 21, 2021, 09:47 AM

markemark

quote:
Originally posted by fuzzy dice:
what happens is I let go of the button and the car does not move...then it launches by itself giving me an awful light usually between .175 and .250...it acts exactly like I am using a delay box but I don't even have one in the car...

Does the engine rpm remain on the lower 2-step rpm during the period (.175 - .250) that you do Not have the TB button pushed (like a delay box) and prior to the trans brake releasing and car moving???

Do you have a playback tach ??

December 21, 2021, 10:46 AM

DON KALINA

THIS MAY HELP OR NOT.....EVERY POWERGLIDE VALVEBODY I'VE SEEN...NEEDS A SHIM OR 2 SHIMS BETWEEN THE CASE & SOLENOID...THE RELEASE STROKE IS NOT RIGHT..THIS CAN

ONLY BE SEEN WITH THE PAN OFF. I KNOW THE GLIDE BUILDERS ON THIS SITE HAVE SEEN THIS...HOPE THIS HELPS..

December 21, 2021, 12:10 PM

vetman

Had a similare issue years ago with a turbo 400.It ended up being in the case recased it and problum went away-internal crack that only opened with enough temp

December 21, 2021, 01:05 PM

Mike Rietow

Put a pressure gauge on the reverse tap to perfect solenoid depth. Screw it in & out in reverse , running.

Highest pressure, shim accordingly.

I suspect this is the op's problem.

December 21, 2021, 07:09 PM

00 DEAD ON

Could it be the SLE opening up really slow at times????

Brian Mollison
2013 American Dragster
2020 Sumerduck Dragway VA Top ET Champion
2017 Sumerduck Top ET & SSS Track Champion
2017 MAC Top ET Track Champion
2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion
2008 IHRA Division 1 Top ET Bracket Final Runner-up
2007 Colonial Beach Dragway Top ET Track Champion

December 21, 2021, 08:32 PM

Eman

Sounds like the problem remained after changing valve body and button.
As someone asked does it stay on the 2 step? Is the linelock wired into the transbrake circuit?

December 21, 2021, 09:17 PM

Stephen Hughes

Maybe reverse clutches have worn grooves in the case and they are hanging up?

December 23, 2021, 06:57 AM

adv ET 266

Have you tried a second proven cast iron valve body yet, complete.

December 23, 2021, 06:59 AM

fuzzy dice

quote:
Originally posted by Footloose:
Have you tried scotch brighting the solenoid shaft? They can get a tiny burr and it can do just what your talking about.

Yes, the shaft has been sanded for burrs...

December 23, 2021, 07:01 AM

fuzzy dice

quote:
Originally posted by Jerry Kathe:
I’m not sure on the FTI valve body if it’s a double dump or not, kinda guessing it is. (call FTI/Greg and find out and also ask their opinion on this) What case are you using and how was it prepared in the reverse clutch area? Are you using the adjustable fluid release orifice if equipped? Does it come out of reverse ok? Other than RPM control, what else is tied into the positive side of the brake solenoid?
Any notable correlation of cold/hot transmission temperatures?

I have a sportsman brake and I spoke with Greg for 40 minutes two days ago...he is stumped as well...

December 23, 2021, 07:02 AM

fuzzy dice

quote:
Originally posted by 329L:
Did you have the issue before you changed the valvebody?

Yes, I had a steel valve body before...same issue with both...

December 23, 2021, 07:03 AM

fuzzy dice

quote:
Originally posted by rusty:
line lock?????

I do have a line lock but it is not on the t-brake circuit...

December 23, 2021, 07:06 AM

fuzzy dice

quote:
Originally posted by markemark:
quote:
Originally posted by fuzzy dice:
what happens is I let go of the button and the car does not move...then it launches by itself giving me an awful light usually between .175 and .250...it acts exactly like I am using a delay box but I don't even have one in the car...

No playback tach...but...when I let go the two step stops...this tells us the electronics are working but we cannot find the issue there...at least not yet....sigh...

Does the engine rpm remain on the lower 2-step rpm during the period (.175 - .250) that you do Not have the TB button pushed (like a delay box) and prior to the trans brake releasing and car moving???

Do you have a playback tach ??

December 23, 2021, 07:12 AM

fuzzy dice

quote:
Originally posted by vetman:
Had a similare issue years ago with a turbo 400.It ended up being in the case recased it and problum went away-internal crack that only opened with enough temp

I have a JW Ultrabell case...been on it since new...

December 23, 2021, 07:13 AM

fuzzy dice

quote:
Originally posted by Eman:
Sounds like the problem remained after changing valve body and button.
As someone asked does it stay on the 2 step? Is the linelock wired into the transbrake circuit?

No, it does not stay on the 2 step when I let go...no, they are wired separately...