ive got a question not about chevelles

but about this truck, i paid 100 bucks for

having been previously pointed in the right direction by members of this site

im turning to you all for help..


i bought a 91 chevrolet 1500 tonight with a replaced motor and a replaced transmission from a buddy of mine.. good work truck...


anyways i noticed driving it it wants to drop into the next higher gear sooner than it needs to.

so eager to make her downshift on a hill i mashed the pedal,

it went to about 5 grand (unaware of the rpm limits on this motor)

it went high rpm then crammed into a low gear then all was normal

until i went to accelerate again, now its having problems

wont shift at the stall wants me to rev it way up then it upshifts.

then for the next gear the same thing, its not shifting with vacum


having not looked at it yet, im thinking its a crack in the vacum hose..


or a vacum modulator?


any ideas, thanks fellas :beers::beers::boring:

(72 chevelle malibu 350 origional 2bbl gm2jet)

Sounds like the TV cable is sticking or out of adjustment. Re-adjust the kick down cable and see what that does.

Dave

I should of asked, is it an overdrive or a 3 sp. auto?

Dave

hey its got 1st 2nd drive and overdrive..


sorry i was outside tinkering



very good!:beers:

Check the kick down cable, make sure its moving ok. Then re-adjust it, by pushing the silver tab near the bracket where it bolts on the intake. Then open the throttle blades , and it will ratchet back out.

Dave

like i said i gave a buddy 100 bucks for the truck,

so i didnt drive it except for on the way home and then some around the block

and country roads, but i noticed leaving his driveway the shift indicator was on

R when in reverse and N when in neutral,

now the indicator is off, coming off of P it goes to R but stays there when i go down

to drive..


Can this cable for the indicator cause this nonsense? Also, i cannot find a vacum line???

flashlight and snow are no help..

302 from a double bored 283 forged crank high nickel block

The indicator is just a little cable that hooks to the steering column. There is no vacuum line on your overdrive tranny. It relies on the kickdown cable which is called the TV Cable. If its out of adjustment or sticking it will cause irratic shifting.

Dave

this is the second transmission ive seen first being my malibu;s
the car has a kickdown on the throttle bracket and a vacum line

so you may imagine my confusion, i skipped over the idea one is a 3 speed

with drive and one is a overdrive.

the cotter pins on the bar linkage underneath look new, which goes with my buddies claim
that the transmission is A not origional and or B recently rebuilt, and i have no reason not to believe him, so im not thinking it could be anything worse than a loose linkage

however is there something you would suggest as a plan B?


very goood, i appreciate all the help!

by the way, did chevrolet produce a 91 heavy half? dad had a 90 gmc 3/4 and

this one says 1500 but it seems just as heavy and stout, it is extended cab, maybe just

the extra frame? also this motor is claimed to be out of an 87 vette and transmission

from a 86 suburban, is this possible? how do i know if this is a gen I or gen II block?

23 degree heads? u know im in a pickle if i want to buy headers for it not certain

what the motor is out of , (casting numbers )

It sounds like the truck has a 700R4 transmission, when you pushed the throttle to the floor, it probably bottomed out the tv valve in the valvebody, and now it's stuck there. Usually this is caused from abnormal contamination inside of the transmission. How does the fluid look? First try to adjust the tv cable, like someone else mentioned. Does it still have the original throttle body fuel injection? If it does, the tv adjustment is easy. Just push in on the metal lock tab on the cable where it snaps into the bracket at the rear of the throttle body, while holding the tab in, pull the outer cable back towards the firewall, and release the lock tab. Now get inside of the truck and push the gas pedal all the way to the floor(with the engine not running of course). You should hear a ratcheting noise, kind of like something plastic just broke, now your cable is set where it is supposed to be. If it still doesn't shift right, then you've got other problems, and need to take it to a professional.

tell you what, i got it to shift with the cable, but

another thing bothering me is how it dumps into 2 and 3rd

at low stall or half way up the rpm bracket for that gear, yeah doesnt a 700r4 have 123 then od?

seems like theres an extra gear in there,

i freed the tv from the bracket tugged on it a while

and it seemed to correct itself, dad had a 90 gmc

so we have the haynes manual, and reading it on adjusting

the tv, it explains it similar to what you just said, however

its lacking in the details on the location of the free up tab

that i push before drawing on the cable from behind.

thank you for your description.

an r4 will hook up to column with the same length cable?

my buddy has a 77vette with an r4, its got a 3rd gear before od

it makes the truck really sluggish when it doesnt go all the way through

first before slipping into second and then half way through second dumping into third if im not sensitive with the gas pedal.


thanks, very good! :beers:

Bryan, Maybe your're feeling the lock-up torque convertor kicking in before the actual overdrive gear. This would make it really bog down. When the convertor is locked in, it is like a direct drive, in otherwards, your input shaft on the trans, and the crankshaft on the engine are turning the same speed. There are many causes for this, I don't know exactly what setup you have, I noticed that on your original post that you thought that the trans came out of an 86 Suburban? In which case the internal wiring is different then what your 91 is supposed to have. Or maybe it has a stuck valve, and even back in the old days, there was a trick of installing a 3/8" checkball in the snout of the tcc solenoid to allow lockup to work, even with no electrical signal operating the system, and they kind of felt like what you are describing with yours.

ooooh i got rot gut this morning that ol ten high

alright
when adjusting the tv cable was mentioned, i tried it.

went out popped the hood climbed up there and

got ahold of the two tabs that hold the cable ends plastic box

to the bracket which keeps the cable sleeve from moving.

I pushed the cable ends box ever slightly out of the bracket

so when i pushed the accelerator it would make it back into

the guides on the bracket correctly and not pop the cable.


yeah its not the most perfect match up of motor to transmission.


i think ill wind up buying a used one and having it done right,

its a very nice truck for how extremely cheap i got it.

and im sure when the guy who gave it to me had the transmission put in there he didnt spend alot of money on it,


id really like to identify my motor and transmission,

dont know where to find the block stamps, or the right one,

and the transmission tag, Ive got a book ill look through and

look up my numbers, then get back to you,


once again thank you very much