okay guys sorry to bother with this again but another problem arose, i took the truck, 78 blazer 700r4 swap, to a local tranny shop to get tci tourque converter lockup kit put in yesterday.  they charged me 200 dollars i get truck back the same day, drive around for a little everything seems fine. today i drive it and i notice that when the truck is in 4 gear and i have a constant throtle on it, i can hear the motor accelerating and decelerating slightly like if i was moudlulating the throttle lightly up and down but im not my foot is steady on the gas so it seems like trans tourque convertor is trying to lock up thus lowering engine rpms but then it dosn't thus cuasing rpms to go back up causing the throttle fluttering im talking about, this is my theory, and this only happens in 4th or overdrive gear, does this sound like a tourque convertoer lockup kit problem, i want to get some feedback before i take it back to trans shop    

The torque converter lockup is pretty simple on a 700R4. It is controlled mostly by a combo of engine vacuum, speed and throttle position. When vacuum drops it will cause converter to unlock. Also if throttle valve cable is out of adjustment it can delay shifts and lockup. Your problem seems to sound like either TV cable is out of adjustment or the effective drive ratio is so tall (combo of tires and gears) that engine is laboring in OD and it cannot effectively lock up properly because engine vacuum is to low. BTW, it is quite normal for it even when locked to unlock when throttle is closed.  

hey snow man what is the deal with a switch pitch converter!! my old shop teacher Mr Glass had one in his 67 chevelle ss396..ohh ya it was sweet,but he did something to it,stuck one in .any ideas? Mudb8??
ohh yea it was a M40 tranny,yes i know the real name of it ,jus wondering if everyone else does hehe!  

Back in 60's GM played around with some variable stator torque converters. It was used in 65 to 67 in Buick's, Old's and Caddies. Kenny Bell has offered a after market kit for this to use in other THM400's for many years. It changes stall from about 1800 to 2600 RPM. But as always, hi stall converters should be avoided in 4x4's because with increase of stall comes more heat and it should not be used to try to make up for lack of proper axle gears. Riding the stall a lot to make up for this can fry tranny.  

the rpm change also could be a vacuum leak from the new kit.

yep, I have one in the chevelle 2200&3800rpm stalls
they do tend to make up for tall gears/huge cam and give it drivability to and from the track.

now.... like snoman is saying, in a 4x4s and tow rigs it's not a good idea to use as a substitute for tall gears and large tires.. the gears are cheaper anyhow.  

wait if vaccum drops it will cause convertoer to unlock?  I thought it would lock when vaccum dropped to a certain amount cuz at idle its making full vaccum and as you accelerate it drops dosn't it?  So my question is how would the thtottle valve being out of adjustment cuause they slight rpm flutter and why only in 4th gear if tourqe converter should also lock up in 3rd gear  

Vacuum is high at a idle and it drops as you advance throttle on load on engine. At a certain point the vacuum switch will unlock it to prevent lugging but it has to be "cleared" to lock by throttle valve position and governor in tranny too. The reason it hunts in RPM is because it is locking and unlocking because it is laboring too hard with tires and axle ratio. BTW converter will lock up in 3rd but only when selector is in 3/D too, not OD setting.  

well when i have it in 3d its fine no rpm ups and downs so do you really thing that 4:10s with 35s would be tall enough to not let the motor pull enough with convertor locked up?  

Geo450racer:
well when i have it in 3d its fine no rpm ups and downs so do you really thing that 4:10s with 35s would be tall enough to not let the motor pull enough with convertor locked up?

Yes, it is too tall. 4.56 would be bare minimum here with 4.88 being a far better choice. The tranny has a 30% OD which is pretty tall and even a 5.13's with 35's would be pretty "tame" cruising at about 2200 RPM at 65 mph in OD.  

ok before i pulled apart my motor i swapped on the stock size tires to see if motor still revved up and down with trans went into 4th gear with a constant pressure on throttle and yes the motor still slightly bounced the rpms up and down a little like the tourque conveter was locking and then unlocking, what could it be? an internal transmission problem or tv cable adjustment prob?  

It is load and RPM related. My guess is that even with close to stock tire your effective ratio is a bit tall and lugging motor to point that vacuum drops enough that converter unlocks.  

how is it too tall?? 4:10s with  like 30 inc tires!! that sounds closer to too deep i really doubt its from gear ratio.  what would go wrong in tourque converter lock up kit installation, im kinda regretting taking my truck to that place cuz i kinda think they suck so either they screwed up the install or something internal but then again it only happens in 4 th gear???????  

pull the lock up solonoid and insert a check ball in the hole, thats the reason transgo uses em in the 700r4 reprograming kit.

sk 700 shift kit now... this is not a performance shift kit, It's a reprograming kit that prevents the tranny from tearing its self up. not to mention fixes the shuttle you already have.

this is my favorite...

700 hydraulic lockup  

Geo450racer:
how is it too tall?? 4:10s with  like 30 inc tires!! that sounds closer to too deep i really doubt its from gear ratio.  what would go wrong in tourque converter lock up kit installation, im kinda regretting taking my truck to that place cuz i kinda think they suck so either they screwed up the install or something internal but then again it only happens in 4 th gear???????

The tranny does not know how much torque is being applied to it directly but rather indirectly based on engine vacuum and TV cable. The OD clutch is not particularly strong in a 700R4 so it is prevented from lugging by unlocking converter via engine vacuum levels then down shifts via TV status. I would suggest that before you tear anything apart in tranny that you get a vacuum gauge on attach it to engine and monitor vacuum level when tranny is hunting to determine is you are suffering from low vacuum causing hunting due to reduced engine performance or if you have other issues.  

also be sure the tv cable is properly adjusted.