izcain

Well another day at the track first run out and trans lets go. I have a reverse manual valve body with Pro tree brake TH-350 all upgraded parts and 36 sprag the guys said the trans was rated up to 700hp. Now I have no Reverse or transbrake feature ( I have tested the silonoid out and can watch it work). The trans also has no third gear anymore. I was wondering what you guys thought could be some possible causes for this problem. I thought maybe a piece of something could have gotten caught in the valve body and is not letting it shift into those gears. Or maybe a possible burned band or something? Any advice would be greatly appreciated!

AlkyIROC

Major oil leak in the forward clutch hub. All three use that hydraulic circuit.

Your forward gears all use the forward clutch. When in first gear and you apply the transbrake, the low/reverse clutch is applied locking the tranny so using the transbrake uses the low "and" reverse circuits.

Are you sure it's third gear that's gone and not second gear?

Check your fluid level. Trying to fill the low and reverse circuits can lower the fluid level down enough that the circuits won't fill.

Pull the oil pan off and see if there are any hard parts in the bottom. I may be a failed sprag which is common on the TH350 even if you have a 36 element one. When shifting in the water box, make sure you're in third gear before letting off the throttle. Being in second gear and having the wheels stop suddenly as they hit drive pavement will destroy a TH350 sprag.

The tranny will have to come out. There's no quick fix.

izcain

Well I am sure it is 3rd gear that has went out in it. I have already pulled then tran back out. Upon taking the converter out and draining it, it had a lot of metal shavings in it so I think something definitly let go!

I understand what your saying about the low and reverse locking together hence me not having reverse as well. thanks for the input!