Guys,

I had my 700R4 trans rebuilt some time ago. It probably has 13k miles on it since. It was rebuilt with the trans-go shift improver kit. Both before and after the trans was rebuilt it would always shift 3-4 full throttle at around 4500 or so rpm. Now the last several times I've been that fast it won't shift. I can get all the way past 125mph with 3.27 gears without it shifting. If I let off the throttle a little it will go into OD but then as soon as I get back in the throttle it downshifts back to 3rd. Other than this condition the trans shifts well. 1-2 and 2-3 are quick and firm at full throttle.

Anybody have any idea what is going on? How can I fix this?

Normally it wouldn't matter as 125 is plenty fast but I'm planning on getting on Pacific Raceway in a few weeks and need probably 140mph for the front straight.

Help please. Thanks.

John