At the race track while manually shifting from 2nd to 3rd gear I get a couple second (well, it may only be a second but it feels like an eternity while you are drag racing) delay between shifts and, even more distrubing, a "flare up" or RPM's during the delay period. On the road it shifts normally and without problem.
First to second shifts are firm and so quick the tires easily chirp even at moderate RPM's. This transmission was put in by the previous owner, custom built to handle horsepower - with kevlar bands and a shift kit, and only has maybe 3,000 miles on it.

Is this just a normal occurance in 700R4's or a sign of pending doom? (The tranny fluid looks and smells fine). How can it be eliminated (I've heard a servo kit will help).

 

I have a Level 2 700R4 built by Bow Tie overdrives and have a different issue. Mine will shift from 1-2 really firmly when at part throttle but when I am at full throttle it just kind of "floats" from 1st to 2nd. 2-3 is FIRM and gets more firm the more throttle that I use. 1-2 is the opposite for me, it's firm at cruising speed and spongy at full throttle.

I am going to and see what responses come up on this.

 

Mine has a slight shudder on the 2-3 shift at part throttle but on WOT shifts, it shifts hard and fine, no hint of a shudder at all. Go figure???

I do get a little hesitation on 3-4 WOT shifts though.

 

I don't rebuild 700R4 trannies. But I do know that the pump size, oil pressure, govenor, and TV cable all determine when and how hard and fast a 700 shifts. So sluggish shifting could be sped up with TV adjustment

They can be adjusted to spin the tires hard on 1-2 shift and 2-3 then bang the 3-4.

I have the TV cable as tight as it can go without limiting full throttle. the correct way to adjust one is with a pressure gauge.

I have 1/2 stainless teflon lines for the tranny cooler. I pulled the stock brass coller reducers off the side of the tranny and put in full 1/2 inner diameter fittings. My tranny shifts harder when really hot so I try to keep the temp down.

I bought from Art Carr a 5000 rpm govenor for street driving and 6800 for racing. It takes about 5 minutes to change it.

 

I have had a 700 tranny since end of '97 in my '72 SB here doing near 400 hp, supposedly....most of them are there anyway....

at any rate, the tranny was a huge mistake from all I know/experienced first hand, and have read about....I should have done a 200 4r, and had done with it...much better unit, lighter, smaller, and too boot more durable, in that the only thing limiting the beef ups on it seems to be the input shaft, from what I hear....

well anyway, the 700 on the first build up lasted allmost 4 years of quick but not overly hard driving, and NO DRAG strip use....

I do have computer DPFI, and so with the initial install had a 2000 rpm vette converter in it.....sometimes I flipped a switch on the console to ALLWAYS lock up the converter in 2-3-4 gears, and so the upshift with alocked converter was super hard and fast.....or sometimes it was just left to the computer which locked at 50 mph and not sooner, so the shifts with that loose converter were hardly felt at all....

well the 3/4 clutch pack crapped the bit one day about 3 years ago, and I replaced it, and also did a 2/4 band, AND a truck converter, so I leave the switch in the computer mode now, as the shifts are quite a bit firmer than with the vette style converter in there, but of course not as good as when locked up....

BUT, now 3 years after that last go round, I have a 9 clutch/steel kit awaiting install this fall, as the unit has flare shifted into 3rd twice so far under moderate throttle....I very seldome go WOT especially on take off and the rear tires just loose it completely, no sense...cost of tires being rather high you know....

so at any rate, it clutch kit comes with a set of instructions about checking the line pressures under various operating conditions, and I found upon reading the 2/4 servo is also HELD OFF applying the band by the higher pressure upon the 2/3 upshift, so the band releases, but sometimes it's not released in time, then the band seems to be stressed as evidenced by the stretching of the Pin hole in the tag end of it staked by a stud...or the beating down of the apply end actuated by the pin....
at any rate, I have not taken down the tranny yet again....going to pull engine this time around also...other reasons why, but this crap will take weeks to accomplish in total....
so I know the rebuild process is considerable more than just a few parts and a kit, indicating this 700 tranny is a real POS from the factory, and upon reading the update and mod files, there are about 200 changes to the damn thing just to TRY to get it to live, and none of them seem too likely to last very long far as I"m concerned....

these new trannies form ANY company are not worth a damn compared to the old C4, C6, 400, 350, Torqueflights of old....

just typical modern cut rate cheap lightweight CRAP, lending to very poor to non existant life under heavy duty/performance use....
neighbor across the street had a ~97 silverado with 150k on the clock and was into/facing his 4TH....700 tranny overhaul and sold/traded the POS....
he did not drive it heave either, just daily transportation....

GENE

 

OK I understand TV cable adjustments and the importance of having it properly adjusted but that would just effect the impact of throttle response on auto-shifting rather than manual shifting, right? In other words, with all else being equal, the TV cable adjustment would not have any impact on manual shifting firmness would it? And if so - would a misadjustment result in firm 1-2 shifts and loose 2-3 shifts?

I also have the "tight as it will go at WOT" setting without the official pressure guage adjustment. I also have a tranny cooler. Hmmm, I would think the tranny would slip more as it heats up.

 

The TV cable is a pressure adjustment so it does have an effect in both manual or auto shifting. I would expect something wrong in the 2-3 area.

I've been very impressed with mine and 4 years of abuse.

Other people driving my car also have mentioned the fact that it really bangs gears when it gets hot. Maybe clearances shrink up??????

 

1-2 shift is done by a band and a servo. The 2-3 shift is handled by a clutch pack. From the sounds of it you either have a. a normal 700r4 3-4 clutch pack that is not set very tight or over all weak line pressure. The 1-2 shiftes are frequently made firmer by use of the Corvette servo, many builder overlook the higher performacne 3-4 clutch packs.

 

My 700R4 does this too.

1-2 is very tight. 2-3 is loose and will allow the engine to rev if I gas it good. If im only driving normal, the 2-3 shift is pretty normal. 3-4 is also very tight shifting with no hint of sloppyness.

The kick-down from 4-3 is very tight also.

Anyone have ideas why 2-3 is loose but 4-3 is tight?

Brent...

 

OK more questions. Now the "corvette servo" (I've also heard of a larger surface "billet servo") that effects 1-2, would that not help the 2-3 shift as well since it will help the 2nd gear disengage? That's assuming one is not in my car, maybe it is, or I can upgrade to the larger servo.
Also will a larger boost valve, which will increase pressure, help?

 

I have a 2-3 flare up on my 700R4 under light acceleration - under heavy acceleration it shifts fine.
I was going to put a B&M shift kit and a higher stall converter (currently it feels like a truck converter) and wondering if it will be worth it.