700r4 3-4 Issues and Fixes

[patmckinneyracing]

Took the malibu down to the exhaust shop today and needless to say it went far from perfect. One issue I need to figure out and resolve is my 700r4 on the highway. The shifting from 1-3 gears is great and good and I know the TV cable is adjusted right. I held the carb at WOT and pulled the slack out of the TV cable for adjustment. But trying to get the trans into fourth gear was a trick and I was manually shifting the trans. I could tell when it engaged but then it felt like it would slip back into third.

http://www.thirdgen.org/techboard/trans ... 3-4-a.html

After reading from the above website post, I guess 700r4's were never meant to shift from 3-4 except when they were used in police applications which involved an upshift kit to allow a WOT shift from 3rd to 4th. I did not know the 4th gear engaged based on throttle position and that some guys are having to back off the throttle all the way to engage 4th and when they barely get on the throttle it downshifts back into 3rd.

Has anyone else had this problem and what are some of the fixes to it? The post above brought up an aftermarket upshift kit to allow WOT shifts from 3-4.

 

[jrm81bu]

Even in stock form it shouldn't downshift with minimal throttle. You should be able to go at least half throttle before it downshifts. Are you absolutely sure what you're feeling isn't the convertor locking and unlocking?

 

[madmaxstyle]

Really? So the police packaged vehicles can lock into overdrive and then put some torque on it?
I blew a motor because OD wouldnt stay engaged over 100.

 

[patmckinneyracing]

The motor is doing 4000 rpm at 70mph when it downshifts to third gear. The TH350 and 700r4 both have a 1:1 ratio in third gear and my motor did 4000rpm at 70mph with the TH350 in third gear before the car went down.

I think I'm gonna take the car to a shop and have them look at the trans and let them set the TV cable and what not.

 

[jrm81bu]

The motor is doing 4000 rpm at 70mph when it downshifts to third gear. The TH350 and 700r4 both have a 1:1 ratio in third gear and my motor did 4000rpm at 70mph with the TH350 in third gear before the car went down.

I think I'm gonna take the car to a shop and have them look at the trans and let them set the TV cable and what not.

Ya, i'd say that was third then.

Really? So the police packaged vehicles can lock into overdrive and then put some torque on it?
I blew a motor because OD wouldnt stay engaged over 100.

My understanding is none of the stock ones were supposed to stay in 4th at full throttle. The valve in the Corvette was supposed to allow 3/4 throttle instead of only 1/2. So it was used as an upgrade. This subject was brought up awhile back and there was some reports of certain vehicles supposedly set up for full throttle upshifts but i'm not sold on that.