440 GTX 727 trans/ Car won't move after it sits for a few days

[T Brashears]

It feeds full time oil into the converter by bypassing the pr valve,that oil charges the converter then leaves the converter going to the cooler then to the rear fitting in the case that feeds the gear train lube. Never tow very far with the rear wheels on the ground without removing the driveshaft. The good thing about that hole is it feeds the converter and lube when max pressure is demanded and the regulator valve is all the way in effectively starving the rest of the tranny to save the friction elements. This is not just a mopar thing.The second style Transgo kit uses a light inner or spring with its own seat to allow the pr valve to move a wee bit before the main pr spring takes over,but has just enough pressure to seat the valve with the engine off. The manual valve is also modified to reduce drain back.
Sonnax makes a pr valve that mimics the line to lube hole with an orifice drilled in the valve and a check ball and spring to close the passage with the engine off.
Wear in any part of the hydraulic system will increase drain back,including the pump bushing.

 

[V_TastyTacos_V]

It feeds full time oil into the converter by bypassing the pr valve,that oil charges the converter then leaves the converter going to the cooler then to the rear fitting in the case that feeds the gear train lube. Never tow very far with the rear wheels on the ground without removing the driveshaft. The good thing about that hole is it feeds the converter and lube when max pressure is demanded and the regulator valve is all the way in effectively starving the rest of the tranny to save the friction elements. This is not just a mopar thing.The second style Transgo kit uses a light inner or spring with its own seat to allow the pr valve to move a wee bit before the main pr spring takes over,but has just enough pressure to seat the valve with the engine off. The manual valve is also modified to reduce drain back.
Sonnax makes a pr valve that mimics the line to lube hole with an orifice drilled in the valve and a check ball and spring to close the passage with the engine off.
Wear in any part of the hydraulic system will increase drain back,including the pump bushing.

So the drilled hole is a brute force caveman mod to fill converter in Park, but it opens a passage to drain back, whereas the new one uses a check valve?

 

[T Brashears]

In a nutshell,yes. The hole you drilled does its job,don’t sweat it unless you’re having more drain back. If you choose to go the Transgo route,you can plug that hole and move on. I use aluminum welding wire.

 

[V_TastyTacos_V]

In a nutshell,yes. The hole you drilled does its job,don’t sweat it unless you’re having more drain back. If you choose to go the Transgo route,you can plug that hole and move on. I use aluminum welding wire.

Haven't built a trans in quite a while. I remember ripping second gear shifts, and sometimes third, but the part throttle shift was too soft for me, so I took the front clutch restrictor out of the Trans-Go TF2. Was a stock rebuild other than the TF2 and 5.0 lever. I kind of makes sense how one change affects shift timing, but knowing how much, and how each change works with all the others will always be a mystery. The number of front clutch springs going up and down based on application, for instance, working with shift lever ratio, servo types, number of clutches, clutch clearance, and accumulator blocked or not. That's a lot to coordinate.

 

[493 Mike]

I just remembered, in one of my old Transgo books there was a recommendation to replace the OEM pump bushing with a (don't quote me) Powerglide pump bushing- tighter clearance.
Mike

 

[T Brashears]

i prefer babbit bushings,easier on the hub.
i check the fit before I change a bushing,if it fits good it stays,don't worry about a few scratches or shiny spots. Hard to get new ones that fit well.
if you change it and think it fits really good,put the pump body on the converter and whack it with a plastic dead blow hammer while rotating it,then remeasure. often it will be close to the original or more often looser. then drive it around the block and remeasure. Often you'll realize you just wasted your time and 5 bucks.
Some trannies can be near impossible to get bushings for.

 

[racingjim]

I had one that had minor grooves in the converter that allowed it to drain back. I never knew about running it neutral will fill the converter faster. I have had several 727 transmissions and everyone of them will have this symptom. The longer it sits, the longer it will be delayed. It is not damaging to longevity.