Transmissions and DrivetrainNeed help with your trans? Problems with your axle?
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Just had my 700r4 custom rebuilt . Everything seems fine, however, this is my first automatic for 12 yrs. It runs thru the gears and locks in, then unlocks with a slight rev. To get it to lock up again I have to accelerate.
Is there a RPM scale where gears should shift? Should'nt the torque converter unlock at acceleration? Would apprieciate any info here. I want to get this right.
A lot of times this is mis-diagnosed on a 700r4. to verify it is the torque converter unplugging the square connector on the side of the trans will eliminate lockup and will let you know if it is hunting the 3-4 shift versus a lockup issue.
How is the converter locking in the first place. is the wiring the correct one for a 1984, ie is it a custom build of your original or is the wiring inside the trans different than your original. Gm did so many different wiring with the 700r4 it may be the internal harness isn't correct for your vehicle.
Just some random thoughts.
note: some early 700r4's don't want the wiring ever disconnected. make sure if you do this it isn't the ecm controlled one.
Thanks ed o, It is a custom rebuild. The way I checked for shifting was to manually control the gears. I just road tested it today and at 40 mph or 80 mph it stays in 4th gear. To get it to lockup, I have to accelerate (pressure on throttle). As long as there is a load, it stays locked up. Also, just cruising at 40 , going up a hill locks it up. When letting off the pedal, you can see to rpm's go up. Really apprieciate the feedback.
Chuck.
Taking control away from the computer will put a stop to this, but you might get a check engine light for it. The kit from Painless Wiring will give you lockup only in OD, and only if you have engine vacuum and aren't touching the brake pedal. But when you lift off the throttle, you have more vacuum, it stays locked. And as long as you ease back into the throttle, it will stay locked. Very pleasant to drive, if you have a mild camshaft. I've enjoyed this kit with everything from a 305 with 2.73:1 axle to a 350 with 3.73:1 axle. It's worth the cost (around $160)
