Is there such a part that I can add to my transmission that will let me go from 3rd to 4th(od) at Wide open throttle and if this part exists what is the GM part # ???

 

Thanks anyway, I found what I needed from B&M!!!

 

I also have the same question, since you know can you please share you information.

Thanks

Kevin

 

The B&M valve will not allow full throttle in OD. It will downshift over 3/4 throttle. You need the GM "B4C" kit.

 

My stock tranny in my 88 Formula allowed me to go 3rd to 4th at WOT. maybe it had the B4C installed.
Here is a little vid I took one night,
http://www.transamws6.com/video/130mph.wmv

 

So let me get this clear. I need the B&M 3-4 upshift kit at wide open throttle and I need some GM B4C kit!!!! What is the part # for the GM b4c kit????

 

You don't need the B&M valve at all, just the "B4C" kit. Do a search and you will find the part #.

 

I have the P# upstairs. I'll post it tomorrow as it's too far to go when I'm this tired.

 

B-Body fix kit:
So our tranny doesn't downshift into third:
Go with GM #8673948. transfixleo

-AND-

You can do the modifications yourself by taking out the TV plunger & sleeve. You will want to block the part throttle 4-3 downshift passages using a small allen set screw in each hole (2). Grind the outside of plug flush, blow off with air make sure plunger moves freely in sleeve, and sleeve goes into the valve body freely. Cost of two allen screws? about .36 cents.
ProBuiltAutomatics

One or the other, don't need both. . .

RBob.

 

Do you have pictures of installing the allen screws? Just wanting to know.

 

http://w1.601.telia.com/~u60113744/t...tranny_wot.htm

RBob.

 

I own an 87 with the 700 R4 and when I swapped engines I left the passing gear cable unplugged, it stays in over-drive at WOT now when it didn't used to. Strange....... still need that kit though so I can hook it back up

 

The only 'cables' would be the TV, gear selection, TCC, and speedo (VSS).

If you left the TV unplugged the trans will fry from lack of line pressure. This would also affect how the trans shifts.

The shift cable and the VSS would be obvious. That leaves the TCC which if left unplugged would not lock up, unless the trans was modifed.

RBob.

 

that passing gear cable you are talking about is a detent cable it doesnt just tell the tranny when u are trying to pass soem one.... you are going to blow ur tranny up by having that un plugged man id hook it back up asap if i were you trust me do a search and you will see that i am right about this...

 

thanks, I didn't know about that at all!!! I appreciate you guys telling me about it, I'll hook it back up today then.

 

Rbob, I'm interested in either of these mods. I looked up 8673948 on gmpartdirect.com and it says "REPAIR PK" $11.80. Is that what I need? It does the same thing that you describe with the allen screws?

Appriciate your help. I'm going to Grattan raceway in May http://www.grattanraceway.com/ (South west MI). It has a 1/2 mile straightaway coming out of about a 50 mph turn. Needless to say, I'm going to need full-throttle overdrive since I have 3.43's. Can't wait, it's going to be nuts!!