New 700R4 Won't shift into 3rd at WOT

[Michael Bennett]

Newly rebuilt from a local shop 700R4 - Specs from the shop: W/ TCI CONTINUOUS PRESSURE VALVE BODY,TCI SHIFT KIT, THE BEAST HD SUNSHELL, CORVETTE SUPER SERVOS, RED ALTOS CLUTCHES, HEAVY DUTY SPRAG ASSEMBLY, WIDE RACE BAND, also has a 2500 rpm lock up converter. This trans is behind my 1980 Malibu with a 400 small block with approx 425-450hp and 3:73 posi rear end. Carb is edelbrock 800cfm Carter style and I have the Edelbrock corrector bracket on the throttle lever. I measured the distance from the centerline of the throttle shaft to the TV connection point at 1 1/8" and I have 1 1/4" travel of the cable from idle to WOT.

The issue I'm having is that it will not shift into 3rd gear at WOT with the TV cable adjusted correctly to be fully pulled out at WOT. 1-2 shift is fine but no 2-3 shift. If I let off or go 85-90% throttle it will shift into 3rd. If I back the TV cable off a 1/8-1/4" it will shift into third at WOT, but the shift is soft. Also, when adjusted like that the part throttle shifts come way quicker than I'd like. If adjusted for full pull at WOT the part throttle shifts are spaced out better.

My trans guys is stumped and I'm starting to think I went to the wrong shop.
I'm starting to wish I went 4L80E, but I already spent the money on this 700R4. Any ideas?

 

[gnvair]

Have you tried another valve body yet?

 

[Mac442]

What type of throttle valve cable are you using?

 

[pontiacgp]

I would spend a little money to bring it to another shop to have it set up by a professional and have them test it. If it still doesn't work you will need a professional opinion to deal with the shop that did the rebuild. The more you play with it the more the rebuild shop will have grounds to say you were the one to cause the damage.

 

[Michael Bennett]

I would spend a little money to bring it to another shop to have it set up by a professional and have them test it. If it still doesn't work you will need a professional opinion to deal with the shop that did the rebuild. The more you play with it the more the rebuild shop will have grounds to say you were the one to cause the damage.

The shop that built it actually manufactures converters. The trans has been back out of the car once already for this issue and they went through and put a new valvebody in and went through the whole transmission again. i am dealing directly with the owner. He said the trans worked great on the dyno and helped set it up himself personally.

 

[Michael Bennett]

I called TCI this morning while waiting for a call back from the shop to talk to him this morning. I wanted to hear what they had to say abut my issue. The TCI rep told me that a 700R4 will not upshift into 3rd gear at WOT with the cable adjusted correctly at full tension. I didn't know what to say. I made sure he fully understood that I was saying 3rd gear and not 4th as I have heard that they won't shift into OD 4th at WOT but never 3rd. I sent them an email hoping someone intelligent would respond.

 

[84cutspreme]

couple of things about the trans. Is governor still stock? I would recommend installing corvette governor. The servo should control 2-3 shift. Check to see if servo is bleeding off. There is a check valve that is known to go bad and not allow 2-3 shift. I am not familiar with the constant pressure valve bodies, how are pressure switches setup? In my setup I only have 4th gear pressure switch to control lockup in 4th. Also not sure but I believe those valve bodies require the 13-vane front pump rotor to keep up with constant pressure. Has yours been upgraded? They sell 7, 10 and 13 versions

 

[pontiacgp]

The shop that built it actually manufactures converters. The trans has been back out of the car once already for this issue and they went through and put a new valvebody in and went through the whole transmission again. i am dealing directly with the owner. He said the trans worked great on the dyno and helped set it up himself personally.

the reason for my suggestion was due to this in your initial post......"My trans guys is stumped and I'm starting to think I went to the wrong shop"......... .

 

[Michael Bennett]

couple of things about the trans. Is governor still stock? I would recommend installing corvette governor. The servo should control 2-3 shift. Check to see if servo is bleeding off. There is a check valve that is known to go bad and not allow 2-3 shift. I am not familiar with the constant pressure valve bodies, how are pressure switches setup? In my setup I only have 4th gear pressure switch to control lockup in 4th. Also not sure but I believe those valve bodies require the 13-vane front pump rotor to keep up with constant pressure. Has yours been upgraded? They sell 7, 10 and 13 versions

The governor is a stock one, not sure what it was out of but but it had pretty light inner weights, it was allowing 6000 rpm 1-2 shift. I changed one inner weight to a slightly heavier one off another facotory governor I had and it reduced the WOT 1-2 shift to 5200rpm. With the cable at full pull, no 2-3 shift. With 1/4" slack 2-3 happened at around the same but shifts were soft and part throttle shifts too early.

Not sure about switche, but I do know that with the TCI lockup kit they installed the converter only locks up in 4th gear.

Next time I talk to the guy I will ask him about the front pump rotor and how many vanes, that is a good point.

It's supposed to have a corvette servo in it.

 

[Michael Bennett]

Have you tried another valve body yet?

Yes, unfortunately this is the second time with this trans. The first time it was flare shifting the 2-3 at heavy but not full throttle after downshifting and then upshifting again AND wouldn't do 2-3 under WOT. They swapped the valvebody and went through the whole trans again. Said it was good on the dyno, but talking to him today, their transmission dyno doesn't go up to 6000 rpm so they wouldn't see this condition on their dyno.