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Transmission Gurus...a question

Posted: Sat Oct 01, 2011 7:46 pm
by BracketNova
Had some trans brake related issues this weekend...

The car seems to be having issues with the trans brake holding. I went out Friday night first two passes went great trans was 120° first pass, came right around again trans was 165° on the second pass, around again trans was 190° and acted like the trans brake wasn't even on.

Same deal Saturday but without hot lapping. First two runs were great third run the trans was at 180° and acted like the brake wasn't engaged. I inspected the wiring and thought it might have been a bad connection, re did the connectors. Went out again, the car moved forward a bit (which it usually never does) when I brought it up against the converter, but held. Trans temp I believe was around 170°. The next two passes the brake held but the 60s got ~.01 worse each pass. The car had rests between rounds and the temp was again around 170° or so.

Someone had said my lower band may need adjusted :smt102 I've never done this.

I did remove the alternator for this weekend, could that have something to do with it? I use an optima red top. Charged it before I went everytime on saturday. :scratch:

The trans is the only thing I outsource on the car, everything else I do. I like to learn but not when it costs me $400 or $1000 - I was heading into the finals. banghead:

On a positive note...new personal best 7.06 @ 95.97 :mrgreen:

Re: Transmission Gurus...a question

Posted: Sat Oct 01, 2011 11:05 pm
by wikd69
Whose valve body are you using ?

I have a TCI on my TH400 and it seems that it will sometimes hang the brake from locking for just a split second, just enough to push me through the beams...

I've learned to get on the break a lot earlier, way before I nailed the throttle...

Re: Transmission Gurus...a question

Posted: Sat Oct 01, 2011 11:58 pm
by BracketNova
I don't recall who made it. It's not had a 'delay' problem if you will in the past :scratch: I generally hit the button when I stage and hit the throttle after I release the button (delay box).

I may need to rig up a pressure gauge, just wanted to see if it's something I need to adjust before I go to the trouble.

Re: Transmission Gurus...a question

Posted: Mon Oct 03, 2011 8:25 pm
by BracketNova
Thinking it was taking the alternator off. I only have one battery, so I'd imagine other components were competing for juice.

Re: Transmission Gurus...a question

Posted: Tue Oct 04, 2011 11:20 am
by Bruce69Camaro
Sounds very similar to a problem my co-worker had with his Mustang.

All he did was change from a manual valve body to a trans brake in his C4 and that's when all the problems started.

He had a TCI trans brake and he sent it back two times to be checked out and each time they said nothing was wrong.

He then sent the trans back to the tranny shop and they said it was indeed the T/B.

He got tired of messing around so he replaced it with a Trans Specialties T/B and the problem went away.

I'm not saying that's the problem, but your story sounds very similar.

Re: Transmission Gurus...a question

Posted: Tue Oct 04, 2011 11:25 am
by Hnrywho
Congrats on the new personal best! Looks like the improvements you made helped. :thumb:

Re: Transmission Gurus...a question

Posted: Tue Oct 04, 2011 7:46 pm
by BracketNova
Thanks Hnrywho


I'm going to put the alternator back on and see how it goes. If I hadn't made any changes and theses problems surfaced I would start looking at the tranny. But I think my best bet is to put it back to the way I had it :roll:

My friend that built it used Trans Specialties parts so I'd imagine thats the valve body that's in there.

Re: Transmission Gurus...a question

Posted: Wed Oct 05, 2011 8:26 am
by luv454
In the past I had a transbrake solenoid go bad. It would work fine first couple passes then nothing. When the solenoid gets real hot it quits. Reach under the car and touch the solenoid after a pass. Carefully! Or check the wire going to it make sure it did not burn into.

Re: Transmission Gurus...a question

Posted: Wed Oct 05, 2011 7:25 pm
by BracketNova
That makes sense. I'll check it out.

Re: Transmission Gurus...a question

Posted: Fri Oct 07, 2011 10:16 pm
by BracketNova
Well gents it looks like it indeed was a voltage problem. Didn't miss a lick tonight.

Also on a positive note.... Ran a 7.1772 in the right lane, next time up ran a 7.1771 in the left. :bling: The air was 40' better the second pass.

Re: Transmission Gurus...a question

Posted: Sat Oct 08, 2011 1:44 am
by wikd69
BracketNova wrote:Well gents it looks like it indeed was a voltage problem. Didn't miss a lick tonight.

Also on a positive note.... Ran a 7.1772 in the right lane, next time up ran a 7.1771 in the left. :bling: The air was 40' better the second pass.
Cool beans !!!! Nice runs :thumb: