The Stovebolt Site Forums The Shop Area The HiPo Shop Turbo 400 to 4l60e swap

What all is required to do this? Working on plans for the '72 Sprint. In need of overdrive!

The 4L60E is a computer-controlled 700R4- - - -they just changed the name to protect the guilty. The swap to OD is much simpler if you don't get into all the electronics, and there are a LOT of 700's out there. Find a S-10 with a 4.3 L V6 in it, and it will probably have a 700 behind the engine. Get the trans rebuilt with the Corvette OD clutch drum, and do your homework well on the geometry of the TV cable linkage. Mechanically, the two transmissions are almost identical, and you can even wire up the torque converter clutch system without having to get into computer controls.
Jerry

+1 on avoiding the 4L60E to avoid the hassle on the electronics. Get a Turbo 700R4; if I remember correctly, the post '93 are the best from the factory. The TV cable is crucial, it is not a kick-down cable as in TH350 or TH400, if you do not adjust it well, the trans will die very quickly. The OEM cable and carb bracket (junkyard) are very easy to set up, or look into the aftermarket. You also need something to lock/unlock the converter (bow tie overdrive.com). And of course probably a new driveshaft. A lot of 700R4 have an electronic speed drive on the tailshaft housing: if you want to connect a speedo cable, swap the tailshaft housing for one from an older 700R4 with cable drive. And at the same time, change the speedo gears to get an accurate speedo.

The OEM vacuum switch and the right brake pedal switch will handle the converter lockup duties without getting into the aftermarket ripoff stuff. There's nothing better than what the GM engineers designed in the first place! The vacuum switch, brake switch, and valve body switch need to be in series, so all of them are closed to energize the TCC. There's also a sneaky little trick on the valve body switch- - - -raising the converter clutch lockup speed by installing a higher pressure switch will prevent "chuggling" in and out of lockup at city driving speeds. The closing PSI of the grounding switch on the valve body roughly corresponds to MPH, depending on the rear axle ratio.
Jerry

Jerry

You may want to also consider a 200r4. Gears are more even than the 700r4 1st to 2nd. Driveshaft may need to be longer for a 200r4. The 400 turbo tailshaft will determine if driveshaft will need modified for a 700r4. Yoke will need changed from 32 spline to 28 for a 700r4 or 200r4.

It would be hard to run fast enough to give me a 2004R. They've got all the gremlins that made the 200 Metric a nightmare, plus an overdrive section and an overly-complicated variable-volume vane type pump. They do make a pretty good anchor for a medium-sized boat, though!
Jerry