I have a V6 with a TH 700-R4 which now goes nowhere in OD. It behaves normally in D, 2 and 1, the changes are ok and there are no strange noises. Does anyone have any ideas what it could be?
Thanks
Ian

 

Hey, that sounds exactly like what happened to me.

I was told by Dana at Pro-built that the input sprag most likely blew up. To fix it, you have to pull everything out, so you may as well do a rebuild.

Depending on how well you baby your tranny, it can last a while like this. For example, I blew mine up during spring break 2002(march/april), and it finally completely died on my on Wednesday, December 11, 2002. Right now I have my new one on the way, and my camaro has no forward gears left. When those blew, I had to drive home backwards, the whole way....good thing the cops didn't show up.

It may not be what you want to hear, but when you loose a gear, then you've gotta rebuild it anyways.

I got mine out of the classifieds for a good price and will be putting it in myself, which will save me a whole lot of money.

Good luck,
Jesse

 

Either the sprag is toast, or the overrun hub broke. The only fix is to pull it out and replace the failed components.

I would fix it ASAP, because the only reason you can move in D, 2, and 1 is because those ranges apply the overrun clutches to prevent the sprag from freewheeling on decel (engine braking). There are only TWO friction disks in the overrun clutch setup and WAS NOT designed to handle the torque of vehicle acceleration. If you keep driving like that, they may very well fail soon.