Burnout91

Hello,
The 700R4 trans in my 91 L98 Z28 does not want to shift from 2nd to 3rd when I have the pedal floored; I have to back off slightly to get it to shift. Do you think this is a malfunction in the transmission, or do I just need to "tune " the governor?
Thanx 3rd Genners!
Bill

IROC212

iTrader: (1)

I would start with the easy stuff first, Fluid level and condition. Then make sure the TV cable is adjusted correctly. If that doesn't help there could be something stuck inside one of the valves in the valve body, or worse case is the 3-4 clutches may be on the way out. Does it shift ok at part throttle?

rjt76

governor problem.

Burnout91

Thanx guys,
The tranny works great overall, has Kevlar 2-4 band and 9 disc 3/4 clutch pack from Mike's Transmission in Lancaster, Ca. Trans has 57,000 miles on it, and I get on it (HARD) regularly. I think it is the governor; I want to work on it soon. This late 2-3 shift has started happening since Mike's put in a stock governor while working my trans. Before I took it to Mike's, I tuned the governor with the B&M Shift Point Kit... I put the lightest springs and heaviest weight in; acted like a manual shift trans...shifted instantly when I moved the lever (Bitchen!!) BUT, under normal driving (in D or OD) it shifted way early and would not downshift when I punched it. So , I need to get it somewhere in the middle, with governor tuning.I think the 700R4 is a great hi-perf trans; chirps 3rd if I push the issue!
Bill

Burnout91

rjt76
Do you have any special insight about the 700R4 to impart to fellow 3rd genners? I'll tell you folks, I bought this car new 12/24/90, and have been doing a science project with her ever since....may not know EVERYTHING, but I've deffinately been around the block with your're average mods, and want to learn, and share my experiences!
Bill

Pro Built Automatics

If everything checks out, TV cable adjusted correctly, and fluid level is correct, and the condition of the fluid is good. Then install the governor that had the 2-3 shift at WOT working. If the 2-3 WOT shifts still has a problem, then it is most likely the 3-4 clutch pack going away.

rjt76

the governor in mine took some playing with to make wide open shifts and downshifts acceptable. I also changed alot of things at once tranny, motor, rear end 3.73 gears. Have you changed anything lately?
what did you do to make this happen? or did it just happen?
I am curious as to what the 3-4 cluch pack has to do with the wide open 2-3 shift. As i know nothing about rebuilding the 4L60...
pro built automatics would be your man not me....

pro built, I have a question what would make the 4L60 not shift wide open 2-3 in drive3 position but work great in overdrive selection??? is it something to do with a line pressure increase in drive3? I have always had this issue unless I calibrate the tranny for the drive3 selection with more governor tuning (alot more weight). But then the overdrive selection shifts early like 1000rpm early?
Basically there seems to be a line pressure increase in drive 3 vs overdive selection. when shifting maually I have to go 1 to 2 then 2 to overdrive or the shift does not happen unless I lift while in drive3. thanks alot... by the way 1 to 2 works excellent reguardless of the position.

Fast355

iTrader: (2)

I know exactly what you are talking about and have experienced it myself. I can watch the line pressure rise when the transmission is shifted from 0D to D and watch the IAC open a couple of counts on a scan tool. The line pressure definately increases. WOT 1-2 shifts in 0D are about 5,000 rpm, WOT shifts in D are about 5,500.

Drive 3 Run

http://youtube.com/watch?v=koWaPeAu3hg

OD run

http://youtube.com/watch?v=GeyY5UZ0V6I

rjt76

yeah but i got the pressure increase whats seems like double that. I wonder how it can be altered to less? thats the only thing about this level 3 that i wish i could fix. I messed with it alot governor wise but i was never satisfied with the results. I was calibrated to 5000 rpm overdrive selction and it sucked and still the drive 3 was like 6200 2 to 3. I am at 5800 or so wide open 2 to 3 overdrive slot currently. the part throttle shifts are good also. except manually shifting is too dificult with the 2 spot move and i like to do that stuff....