727 Shifting issue

[Rakishi64]

I've been having issues with my rebuilt 727 for a 340. It shifts from 1-2 at 20mph, and 2-3 at 50+ after I lift my foot off pedal. Also, sometimes it won't downshift to 1st gear at a stop.

Tranny shop that rebuilt the 727 says it's likely a dirty governor issue. However, I just noticed the spring attached the kickdown linkage (not the throttle return spring) was missing. Could this be the culprit? Any help is appreciated.

 

[Dave6T4]

If the kick down lever on the transmission does not come to complete rest (aided by missing spring), the transmission will not shift to LOW at stop. The shift speeds are adjustment of kick down linkage per shop manual.

 

[Rakishi64]

Rgr that makes sense. Looks like I'll get a spring and readjust the kickdown again. I appreciate the help.

 

[Wietse]

The shifts are balanced between the Throttle pressure and governor pressure, say at WOT throttle pressure is high and will force the delayed shift point as it overcomes the governor pressure.
While normally increasing speed there is low throttle pressure and governor speed will overcome it at some point and cause a shift.
Like Dave said, get the spring and set the throttle linkage first. Probably that's all it needs.

 

[66Satellite47]

With a stock setup the spring is required. And proper adjustment of the linkage.

 

[Rakishi64]

Ok got it, thanks for the info everyone. I hope this fixes my trans issues. Been a PITA.

I have a Edelbrock carb and stock kickdown linkage..only kickdown linkage for a 727 340 I found was this on year one, also got a new throttle spring.

 

[dvw]

Start with the spring for sure. The governor can be accessed with the trans in the car if necessary.
Doug

 

[Lefty71]

Start with the spring for sure. The governor can be accessed with the trans in the car if necessary.

I agree with this 100 percent....but bear in mind that dirt or another issue in the valve body can simulate these issues since the fluid flow from both the governor and the kickdown passes thru valves in the body..... If you do decide the pull the pan, check the function of all valves in the body while you are in there. I would suggest a trans book before going that far.... $ 30.00 is nothing when it comes to preventing further issues and potential damage.

HTH, Lefty71

Torqueflite A-727 Transmission Handbook HP1399: How to Rebuild or Modify Chrysler's A-727 Torqueflite for All Applications: Munroe, Carl: 0075478013999: Amazon.com: Books

Chrysler TorqueFlite A-904 & A-727 Transmissions: How to Rebuild (Workbench How-to): Hand, Tom: 9781613253359: Amazon.com: Books

 

[66Satellite47]

I agree with this 100 percent....but bear in mind that dirt or another issue in the valve body can simulate these issues since the fluid flow from both the governor and the kickdown passes thru valves in the body..... If you do decide the pull the pan, check the function of all valves in the body while you are in there. I would suggest a trans book before going that far.... $ 30.00 is nothing when it comes to preventing further issues and potential damage.

HTH, Lefty71

Torqueflite A-727 Transmission Handbook HP1399: How to Rebuild or Modify Chrysler's A-727 Torqueflite for All Applications: Munroe, Carl: 0075478013999: Amazon.com: Books

Chrysler TorqueFlite A-904 & A-727 Transmissions: How to Rebuild (Workbench How-to): Hand, Tom: 9781613253359: Amazon.com: Books

Lefty, I agree that learning how a 727 works is really important.

 

[Wietse]

It's actually a very simple hydraulic schematic.
Unfortunately the books schematics are prehistoric in relation to modern hydraulic schematics.
I learned to read, make and understand modern versions, perhaps some day I will convert it for ease of understanding.

 

[66Satellite47]

I thought the hydraulic schematics in the FSM were pretty straight forward. But I do think understanding how the combination of all internal parts and how they relate is important. Your advice in post #4 is good.

 

[Wietse]

But I do think understanding how the combination of all internal parts and how they relate is important.

There are a few functions inside the transmission hydraulics that always have a different outcome and none of them could be seen on the drawings regardless, you will need all info on spring pressures of the valves, surface area's of the pistons that are pushed on from different sources. Hard to get all that and always have the right outcome.
That TransGo guy had that all figured out on many transmissions and knew exactly where it could use more pressure, stronger/weaker spring or a different size valve (piston) to improve the functioning. I think that is a work of art if you manage to figure all that out.

 

[66Satellite47]

There are a few functions inside the transmission hydraulics that always have a different outcome and none of them could be seen on the drawings regardless, you will need all info on spring pressures of the valves, surface area's of the pistons that are pushed on from different sources. Hard to get all that and always have the right outcome.
That TransGo guy had that all figured out on many transmissions and knew exactly where it could use more pressure, stronger/weaker spring or a different size valve (piston) to improve the functioning. I think that is a work of art if you manage to figure all that out.

I agree the internals of the valve body make a difference. My only experience with TransGo was excellent in my tow vehicle.
My drag race experience has been with one Mopar modified manual VB, Turbo Action Cheetah Reverse Manual, Griner brake and recently Cope Reverse Manual.
My point was that the combination of clutch pack springs, number of clutches and the material, servo lever ratio, servo springs all make a big difference.

 

[Rakishi64]

Thank you for all the advice. I got the manual and will be going through it....although, going back to my FSM, I believe the car came with the wrong kickdown linkage rod. Mine appears to be for a big block. That and the spring would explain a lot I believe.

Two pictures below. The first is the correct rod for a small block 4bbl. The second is the one my car has, the Big block rod.

 

[66Satellite47]

If I recall the EDE carb has a different throttle shaft lever than the OEM carb would have. That may be part of the problem. I did a lot of playing around with my mismatched aftermarket carbs & the stock linkages. It can be done, but may take a lot of trial & error.

 

[Rakishi64]

Yeah this car has a lot of random mismatched parts and short cuts from the previous owner. Luckily they do have the correct Edelbrock throttle shaft lever, part 1481. I think I'm just going to get a bouchillon cable, and call it a day given the hobbled together parts.