Won't shift into OD at WOT

[Black Box]

My GN won't shift into OD at WOT. It just stays in 3rd gear. But if I back off to about 7/8 throttle, it hits OD (pretty hard I might add) and the car takes off almost like it has a 75 shot of N2O. Once it's in OD, I can gas it a little bit more, but if I floor it, it'll downshift into 3rd gear again.

What can I do to fix this? Is there a specific valve that needs modification?

There's nothing otherwise wrong with the trans, it's got about 5000 miles on it since it was rebuilt. It works awesome, I was just curious why it doesn't like WOT with OD.

Thanks
Steve

 

[WE4]

Originally posted by Black Box
My GN won't shift into OD at WOT. It just stays in 3rd gear. But if I back off to about 7/8 throttle, it hits OD (pretty hard I might add) and the car takes off almost like it has a 75 shot of N2O. Once it's in OD, I can gas it a little bit more, but if I floor it, it'll downshift into 3rd gear again.

What can I do to fix this? Is there a specific valve that needs modification?

There's nothing otherwise wrong with the trans, it's got about 5000 miles on it since it was rebuilt. It works awesome, I was just curious why it doesn't like WOT with OD.

Thanks
Steve

Are you SURE you have a brf or equivelent VB? The regular ones will not WOT into 4th. Ck VB code first, then proceed. If you do not have a Perf VB (oz, kz, brf, bq, cz, cq,) It can and may do that. PTS has a throttle valve sleeve that will cure it if you so in fact do not have the correct VB.
But ck that first.
Bruce
WE4
www.PTSXTREME.com

 

[Black Box]

Yep, positive. Trans is tagged BRF and the VB had the correct identification markings (BR3 I believe) on it for a BRF valve body. Been almost a year since I had the pan off, but I remember checking it, and it was in fact the right trans and VB.

Steve

 

[WE4]

OK...

Originally posted by Black Box
Yep, positive. Trans is tagged BRF and the VB had the correct identification markings (BR3 I believe) on it for a BRF valve body. Been almost a year since I had the pan off, but I remember checking it, and it was in fact the right trans and VB.

Steve

What about the TV sleeve and plunger? Are they extremly loose or worn? Does it have the correct bore and sleeve. It could still be a BRF and someone screwed with the TV plunger and sleeve. Your issue is there somewhere as that is the controlling factor. What RPM does the govenor upshift at 1-2 and 2-3 at 180 degrees?
Are they consistant? And is 4th on time except for WOT?
I realize this sounds like a bunch a jumble, but the info is what will help us to narrow it down.



Chris? CK? Any input? Ideas?


Bruce
WE4
www.PTSXTREME.com

 

[Black Box]

Bruce,
Upshifts are on time, and at WOT occur at 4900-5000 RPM on the 1-2 and 2-3 at normal operating temps.

I'll check the fit & wear on the TV valve when I drop the pan next Saturday.

Thanks for the help.
Steve