transmission recommendations?

[travisr1988]

Vile, I considered that, but that would mean new driveshaft, carrier, ring and pinion, brackets, etc on top of new transmission and torque converter. I need more cost effective for now. Eventually, when finances allow, I'll build a 383 and back it with a 700r4 and 4.10/4.11 rear gears.

[VileZambonie]

There are a bazillion of these trucks in junk yards with that configurations and all of the parts you need. I can't see spending any money on a TH350 or 3 speed anything these days.

[travisr1988]

I have a question on th350 transmissions. Why would summit and jegs branded th350s not have provisions for kickdown cables? wouldn't I want a kickdown?

[rich weyand]

When you get on the throttle, intake manifold vacuum falls, the vacuum line to the transmission releases the diaphragm on the vacuum modulator, which increases hydraulic pressure to the governor, which has to spin faster for the centrifugal weights to overcome the piston pressure on the valve and open the valve to enable the shift.

What the kickdown cable (or kickdown switch) does is cut the modulator out of the circuit -- basically it bypasses it -- providing full pressure to the governor.  This will require the governor to go to its programmed (by the selection of weights and springs) highest-rpm shift point.

The benefit of the kickdown switch is that it happens faster than the vacuum signal to the modulator, so the shift happens quicker.  Also, the modulator at 0 vacuum does not provide full pressure to the governor.

I think some modulators can be adjusted to give earlier downshifts/later upshifts, but I prefer having the kickdown to bypass the modulator entirely and run the shifts right off the governor at WOT.

[travisr1988]

Thank you Rich, it definitely sounds like I want a kickdown. Does anyone know any good transmission builders in the north Austin area who back there work?

[travisr1988]

So, I parked the truck some time ago when the tranny started acting up and only started it every couple weeks and moved it around a little. Now it loses very little fluid as opposed to the 2 quarts daily or more, and doesn't seem to have any problems shifting, although I haven't been on the highway or above maybe 40mph, could it have been trash in there somewhere causing the problems and leaks and it cleared up? It showed signs of failing front pump, failing governor, and was making awful noise, shifting really late at light (almost idle) throttle (sometimes wouldn't shift unless I snapped the throttle) and leaked like crazy.

[rich weyand]

The governor is stupid simple, and its only common failure mode is a trashed nylon gear.  Pull it and look at it.  5 minutes.  It's behind a cap secured with a bail on the side of the transmission.  You might leak an ounce of ATF when you pull it.


Sounds more like the regulator is shot.  Also an easy replacement.