hello:
my truck is the 92 fs blazer tbi 350. only thing i have done to it is the flowmaster 40 muffler on a 3 inch exhaust. my issue is my trans is only 11k on the rebuild, i found the receipt from the previous owner from aamco. the problem i dont like is when driving this normally everything works /shifts fine but it takes until about 45mph or 1-3 mph or less than that for the thing to shift into 4th. as im accelerating keeping a steady foot on the pedal keeping rpms right about 2k or a smidge under it accelerates fine but get around 35-38 mph the power drops off and i gotta give it more gas to get it about 45 mph then the shift occurs and i can feel the torque set in and i can let back off the gas and it accelerates just fine, but as i do let off now the tc lockup occurs. it just doesnt seem right. the tv cable is properly adjusted. now when deaccelerating the thing wont come out of 4th until about 38 mph but if im above that and accelerate, it does just fine. My question is can I adjust something or do something to the trans governor or valve body to bring that 3-4 shift down to about 35 ish 38 ish when accelerating. this is a 700r4 trans.

any help is appreciated.

right now stock its averaging 10-13 mpg and im trying to figure that out right now. im sure this shift from 3-4 dont help it either.

thank you,
Scott

 

You can change out weights and springs for the governor. There are some good threads about it if you look. Thirdgen.org would be a good place to start. I do know that a pressure gauge for watching line pressure helps as far as troubleshooting and getting shifts set with the governor. If you do it anytime soon make sure to post back because I need to do the same thing in my car.

 

I've read about changing out the weights in springs on the governor. I am tempted to do that however it's going to change the rest of my shift points which I don't want to do. I just want to change the 3 to 4 shift down to about 35 to 38 miles an hour. it May be awhile till I get to that point. I.gotta replace the valve seals in the engine. And try to figure out why my truck at stock height and all with a flow master 40 is getting 10 to 13 mpg when others are getting 15 to 18. Something is not right.

 

The 700r4 shifts based on line pressure signal based on the TV cable off the throttle. My best guess for raising/lowering a specific shift point would be to find the spring in the valve body responsible for the shift and either increase the spring size to raise the shift point or decrease the spring size to lower the shift point. Just a guess though.
I made a thread about 700r4/4l60e that has a fluid diagram of the 4l60e valvebody. That may give some indication as to which spring does what.