727 is acting up... short 1-2 shift and won't part throttle kickdown

[Smokinnjokin]

Friends,
I have a 727 (70's, with part throttle kickdown vb) 360 combo in my Satellite that I have been driving for years with no big issues, several cross country road trips and mixed driving. 3-4 years ago I freshened it up with some band adjustments and sent the VB off to get checked. My kick down is adjusted correctly and previously worked great. Shift points were around 5k 1-2 full throttle and around 5400 2-3. Suited my driving fine. Lately, it has been acting up- won't do part throttle kick down anymore, has to be floored. And now my 1-2 shift is around 4k rpm at full throttle. Shifts still feel firm, it's just the shift map is way off as if the kickdown is out of adjustment. Again - haven't changed any setting since it worked perfectly, checked entire kick down path everything is correct. What gives? Am I losing pump pressure?

 

[RJRENTON]

Friends,
I have a 727 (70's, with part throttle kickdown vb) 360 combo in my Satellite that I have been driving for years with no big issues, several cross country road trips and mixed driving. 3-4 years ago I freshened it up with some band adjustments and sent the VB off to get checked. My kick down is adjusted correctly and previously worked great. Shift points were around 5k 1-2 full throttle and around 5400 2-3. Suited my driving fine. Lately, it has been acting up- won't do part throttle kick down anymore, has to be floored. And now my 1-2 shift is around 4k rpm at full throttle. Shifts still feel firm, it's just the shift map is way off as if the kickdown is out of adjustment. Again - haven't changed any setting since it worked perfectly, checked entire kick down path everything is correct. What gives? Am I losing pump pressure?

I assume vb = valve body? Wouldn't a 360 use a LA904? Or a 727A? just curious....
BOB RENTON

 

[Smokinnjokin]

It's not the original engine or transmission to the car. and yes, VB= valve body.

 

[MWbirdLOVER70]

I assume vb = valve body? Wouldn't a 360 use a LA904? Or a 727A? just curious....
BOB RENTON

727A but also depends on application to car/motor. Have seen both transmissions behind 360 but in the day most 360’s I’ve seen had the 727A but others will chime I’m sure. Just my expirence

 

[tubalcain]

After the VB checkup and band adjustment, was the transmission sealed up really good with RTV? I mostly try to avoid the stuff. Bits of it find their way into the oil and goof up the valves. I suspect that some got into the governor. That might account for the changed shift points.

 

[Smokinnjokin]

All i did was drop the pan and valvebody, replaced output shaft bushing.. I didnt split the case or use any rtv on the pan. It has one of those flexible gaskets you dont use sealer on. And it shifted great for years after that freshen up. I sure don’t want to crack the transmission open if i don’t have to…

 

[Dave6T4]

I guess I don't understand the bit about sending the valve body out to be checked. What was done, there? Are you using factory articulated kickdown linkage, or aftermarket,like Lokar? If you changed the tailshaft bushing, you would have removed your rear housing. You may have to do this again, and remove your governor weights to deburr/degunk them. Your problem seems to be in governor circuit, or linkage.

 

[Smokinnjokin]

I guess I don't understand the bit about sending the valve body out to be checked. What was done, there? Are you using factory articulated kickdown linkage, or aftermarket,like Lokar? If you changed the tailshaft bushing, you would have removed your rear housing. You may have to do this again, and remove your governor weights to deburr/degunk them. Your problem seems to be in governor circuit, or linkage.

I didn't feel comfortable cracking open the valve body and messing with anything. I sent it off to a reputable transmission shop (I forget who, it's been a long time). I don't remember exactly what they did, but bottom line it shifted great for years after putting back together, many thousands of miles and several long 12-14 hour days of driving on cross country road trips.
Kickdown linkage is factory rods. With the throttle fully open, the kickdown lever on the transmission is all the way back. With throttle closed, there is just a little bit of movement left. Adjusted exactly as the FSM, and again worked beautifully for years with no changes, adjustment, anything coming loose or breaking etc.
Like I said, I changed the tail shaft bushing without removing the rear housing. I have the puller tool. You just take out the slip yoke, remove and reinstall the bushing from the rear using the puller tool.

 

[Dave6T4]

I have rebuilt quite a few 727's in my days, and have seen valve bodies with a cracked internal channel. This is not visible in the outside of the V.B. It is not common, but does happen. It might be worthwhile to swap another V.B. in, and see if situation improves.

 

[dvw]

I have rebuilt quite a few 727's in my days, and have seen valve bodies with a cracked internal channel. This is not visible in the outside of the V.B. It is not common, but does happen. It might be worthwhile to swap another V.B. in, and see if situation improves.

I had one recently with a crack wall next to the throttle valve. It had no kickdown, and early shifts. The easiest way to test? Install a pressure gauge in the accumulator port. Disconnnect the kickdown and manually move the lever full rearward. There should be 90-100psi. If its low it's time to pull the valvebody and inspect it.
Doug

 

[Smokinnjokin]

Just found this cool video on YouTube, was helpful. Going to try to rig something up to take pressure readings.

 

[MWbirdLOVER70]

I didn't feel comfortable cracking open the valve body and messing with anything. I sent it off to a reputable transmission shop (I forget who, it's been a long time). I don't remember exactly what they did, but bottom line it shifted great for years after putting back together, many thousands of miles and several long 12-14 hour days of driving on cross country road trips.
Kickdown linkage is factory rods. With the throttle fully open, the kickdown lever on the transmission is all the way back. With throttle closed, there is just a little bit of movement left. Adjusted exactly as the FSM, and again worked beautifully for years with no changes, adjustment, anything coming loose or breaking etc.
Like I said, I changed the tail shaft bushing without removing the rear housing. I have the puller tool. You just take out the slip yoke, remove and reinstall the bushing from the rear using the puller tool.

Maybe one of the VB valves is plugged or they left one of the check balls out. Maybe accumulator soring “sacked out” after all these years. Maybe governor pressures are off? Sounds like last thing checked was VB and that’s where I’d start