MeanWS6

How exactly does the Gear Vendors Overdrive unit work? And whats needed to install it? Is it worth the cash if you want overdrive on a TH400?

James B.

iTrader: (1)

It takes a long time to explain these in detail. Here's a link:
http://www.fullsizechevy.com/forum/s...threadid=31459

BTW - awesome piece of 100% reliable bulletproof hardware.

MeanWS6

great read - thanks for the link.
When in OD, does the GV unit screw up your speedo? Any PCM tuning issues when in OD and driving on the highway?

James B.

iTrader: (1)

No problem at all. The VSS gets moved to the tailshaft of the Gear Vendors. (With a TH400 in a EFI car this would give you the ability to feed the PCM actual VSS signal instead of using a mechanical VSS signal generator off the TH400 tailshaft.)

The PCM does not even know it's there. The GV does splice the Torque converter clutch circuit so it can unlock it for shifting, but when it does so it keeps the proper resistance on the circuit so the PCM does not detect a fault.

john kilgore

the gv is a 22% od and your 4L60 is 30%. your th400 will have an open converter which if you try to run your engine rpms under your stall it will slip the tc. if you put wide ratios in your 400 you can use your gv to split the gears and get 6speeds call gv 1800 999 9555