New governor for a TH 425

Got a new Allison AT540 governor to see if it would adapt to an TH425 transmission. It does! The Allison governor has no speedo gear but the gear from a TH425 fits on it. The Allison governor has no can as it fits inside the transmission in it's original configuration but it will fit inside a TH425 can. It does fit, shift and the speedo works. The Allison governors were available in several different rpm ranges to go with whatever engine was driving it. This particular governor is for 3000-3400 rpm and is a code 462. Sonnax makes them new.http://www.makcotransmissionparts.com/Allison-AT540.html

Part number on the Allison governor

Speedo gear swapped from the broken TH425 governor on to the Allison.  I think the weights and springs could be swapped and then it would act like a TH425 governor.

TH 425 governor loose yoke

Here is a couple TH 425 governors that have the yoke coming loose.

 Yoke brazed back in place. I submerge most of the shaft in water so none of the fits get hot and change dimension.

 Some of the new gears are different and need shimmed. Got caught on this last time. Got die button shims on order which should work. Need to get these done and back to Jim K.

Another quirk, this governor has an additional spring between the bottom of the spool and gear. First time seen this.

vacation in the shop

                                               Uncanning governors

                                                             Making chips

                    Governor can parts...It took me three days to make 17 of them.
                    Used carbide insert bits for the first time. They cut fast but did                               interesting things with thermal distortion of the parts.

                 Shaper cuts a key slot for a belt pulley reduction.

Testing Corvette style "windowed" primary governor weights

Modified the primary weights to have a "window" like GM did for Corvettes with 700R4 transmissions. This was a removal of about 20% if the weight.
Windowed weight and a B&M kit.
Installed for testing, I found the effect to be very small. If anything it may make the light throttle shifts later. Hardly noticeable..... real changes need to be made with secondary weights and springs.

TH 425 governor cans part 6

A few chips
GMC outside
New Driven gears installed. Notice two styles of shafts. The two on the left are different then the three on the right. The spools are different also.
Nylon gear sets the operating axial position (runs against the dowel in the trans case). The gear with the most wear was .050 different than new. shoulda used the camera flash
Brushing out the bore,
Some of these needed a good wire brushing to get them clean
Sludge
Cleaning out an orifice in the valve spool

TH 425 Governor cans part 1

Leaded steel to make governor cans out of. Machines nice.... lots of chips to come, About $10 a linear inch delivered.