10 Transmission Tips From TCI


Installing a transmission goes way beyond simply bolting it in place. There are several key aspects to look out for before and during installation, and a handful of critical areas that need attention afterwards to ensure proper adjustment and function. Below are ten tips, photos and a video from TCI that will make the job a success.

  1. Read the instructions. We know that sounds simple enough but many people fail to take a minute to look them over. Most guys rip into the transmission like a kid on Christmas morning and throw all the paperwork in a pile with the packaging. Don’t do that. The instructions contain the answers to most tech questions.
  1. Check for proper converter “pullback” using a straight edge across the face of the transmission and measure per instructions. Once installed there generally needs to be a 1/8″ to 3/16″ gap between the flexplate and converter before bolting the two together. It should rotate freely.
  1. Do not “cinch” the transmission to the block with the bolts. Make sure the torque converter is in the proper location and push the transmission to the block. Improper converter positioning can destroy the pump. Remember that it’s easiest to install the converter before sliding the transmission under the car.
  1. Proper detent adjustment on 700R, 200R and AOD transmissions is critical! Failure to do so will result in rapid transmission failure. Follow the instructions carefully for proper adjustment and shifting. When changing from a factory carb to a Holley or an Edelbrock a Geometry Correction Kit must be used. This corrects the throttle geometry for proper kickdown and detent.
  1. Mopar TorqueFlite transmissions need the OEM bellcrank assembly for the kickdown linkage or a cable kit from a company like Lokar. The kickdown linkage controls both line pressure and shifting points, and improper adjustment will result in failure of both.
  1. Vacuum for the modulator needs to be connected to a manifold vacuum port. This controls shift points and is essential to proper operation. The modulator comes preset from the factory, but can be adjusted to alter shift points.
  1. The shift points on GM’s TH350, TH400 and 700R transmissions are controlled by the governor. You can adjust these by modifying the springs and weights with a special kit. When in doubt, use your old governor to retain your old shift points.
  1. Clean the driveshaft yoke before installation. Accumulated dirt can damage splines, clog internal lubrication passages and damage the transmission.
  1. Be sure to flush the cooler lines and fill the system to the correct level. To do so, place the car on level ground, run long enough to achieve operating temperature, and cycle the car through all the gears to fill the internal passages and then recheck fluid level. Also a proper trans cooler is a must for reliability and longevity. Heat kills; remember that.
  1. CALL SOMEBODY! The TCI Tech Line is open for YOU! Trained professionals are standing by.