Having a issue in my dragster where I am getting a flare on the shift Approx 300 rpm. The weird thing is that it doesn't do it on the 1st run of the day, but every run after that is shows up on the data logger. Every time I take the car out it is the same scenario. I have checked the shifter adjustment it seems perfect. Seems like when the fluid gets up to temp it will do it. Any ideas. It has a cast valve body in it. I am contemplating a aluminum VB. I ran one in my old car. Thinking about changing this one over on the new car.

I would try resetting the band first.If its ok cold but not fully up to temp sounds like band slipping

Shift flares can be tricky
Its a timing thing between the band releasing and the high clutch applying. Band release and clutch apply is fed from the same hydraulic circuit coming from the VB. It tees off once it gets to the pump casting. Flare normally occurs when the band is fully released before the hi clutch is fully applied.
Unless you have low line pressure a valve body swap will not help.
Are you logging trans pressure? If so what is it?
For sure check your band adjustment, easy to do and its free and should be part of any normal maintenance program. Personally I like 72 inch lbs and out 3 turns but 3-4 turns should be fine. Count how many turns it takes to get to 72 inch lbs that way you know where it was at before you adjust it.
Could have a bent band adjuster pin, I have been there done that

Do you know what the clutch pack clearance is? Too much clearance can cause a flare due to more area behind the piston to fill

This message has been edited. Last edited by: Big Steve,

quote:

Originally posted by vetman:
I would try resetting the band first.If its ok cold but not fully up to temp sounds like band slipping

The band is low gear

There is a small check ball in the high gear drum. If that ball isn't sealing well ive seen it cause flairing.

Like Steve stated Band first. Critical It should be a maintenance check several times during the season. The check ball issue will cause issues also Perform the pressures check at the servo on the stands in a safe environment. Do this hot.If infarct there is a boost valve and spring issue they make various kits to increase pressures pending there are no other internal issues. just some pointers.

OK. Thanks for all the responses. I will start troubleshooting it and checking these out & see what I find.

Make sure your rooster comb isnt bent or on it's way out (broke around the pinch)

Add fluid?

saw this when I ran hydraulic fluid...

Transmission is full.

quote:

Originally posted by BP758:
Add fluid?

No hydraulic fluid here. FTI fluid is what I have ran for a few years.

quote:

Originally posted by I Hate Dragsters:
saw this when I ran hydraulic fluid...

quote:

Originally posted by Bigdrive88:
Transmission is full.

quote:

Originally posted by BP758:
Add fluid?

Maybe add a little fluid over full of you have a catch can to eliminate fluid running away from the pump? Just a thought

fought a flare for 1/2 a season once ... tried 4 different spring rate servo springs, band adjustments , different rate high clutch springs , leaving some out , different clutch pack clearances , on and on ... finally Marco asked what fluid I was using ... told him a popular synthetic racing ATF ... he said put regular old Type F mineral oil ... walaaa ... NEVER another problem with that trans flaring at the shift .... I use either Marcos fluid now , or Transynd in the other trannys now .. something to try possibly