1964 727 rebuild - It's not right

[Van Stahr]

Had my 727 rebuild a few weeks ago. Apparently this shop is not familiar with MOPAR transmissions.

Before the rebuild, when I suspected the tranny was failing but everything shifted fine, I could barely get the wheels to turn power braking. Now it will smoke the tires, so it's definitely working better.

The guts were trashed so they replaced everything. However, it is not functioning correctly.

I start it up, put in R and back out of the driveway. Move to D and drive down the street to the stop sign. Move to L and nothing happens. Move to 2, nothing, then D, nothing, R seems to work. Put it in P and then shift down to L and it goes, and shifts to 2 and 3rd in D.

I adjusted the kickdown according to the manual and that improved the overall performance, and I think the shift adjust needs tweeking, but the sequence above still happens.

 

[Lefty71]

Couple possibilities.... there are many. Definately start with shift cable adjustment first tho. They cracked the valvebody (early units are prone). I can show u where. They backed off the line pressure. Or they broke a sealing ring on the input? shaft.

 

[Van Stahr]

The line pressure was my first though as well. To adjust that you have to drain the fluid and take the pan off, correct?

I have not done a tranny rebuild before, but if I had it at my little brother's shop we would have given it a go.

 

[Lefty71]

The line pressure was my first though as well. To adjust that you have to drain the fluid and take the pan off, correct?

You can measure, but not adjust without pulling the pan. A tranny service manual, or oem for your car will help here.

 

[turbine68rt]

Agree with lefty on checking the shift cable adjustment as per fsm procedure.

 

[493 Mike]

Sounds like the rear clutch is not engaging. It is used in forward ranges, not used in reverse.
Mike

 

[Dipstick]

If the shift cable adjustment is in question, remove the NSS and shift to N. The cock's comb contact should be centered in the hole in P and N. Might need a mirror to see up there.

Warning, removing the NSS will result in some fluid loss, have a catch can handy.

 

[dvw]

Sounds like cable adjustment, or the cable is possibly melted/binding. If the rear clutch was slipping it it wouldn't have worked at all in the forward gears. Best way to adjust is with the pan off. Shift from reverse to neutral, then 1st neutral. Adjust so the prong on the rooster comb is as close to the center of the safety switch from each direction as possible. The wrong neutral switch will bind on the rooster comb prong. Is the switch different from before?
Doug

 

[Van Stahr]

Sounds like cable adjustment, or the cable is possibly melted/binding. If the rear clutch was slipping it it wouldn't have worked at all in the forward gears. Best way to adjust is with the pan off. Shift from reverse to neutral, then 1st neutral. Adjust so the prong on the rooster comb is as close to the center of the safety switch from each direction as possible. The wrong neutral switch will bind on the rooster comb prong. Is the switch different from before?
Doug

That I don't know. Hopefully I can get some time in the next few weeks to adjust the shift cable. If that doesn't fix it I will probably drop the pan and check that all out.

 

[Van Stahr]

You can measure, but not adjust without pulling the pan. A tranny service manual, or oem for your car will help here.

I got one on CD a few months ago on ebay. It has been helpful.

 

[1 Wild R/T]

The way the service manual says to adjust the shift cable is shifter in Neutral, disconnect the wire going to the neutral safety switch, hook up a test light to the switch & the battery... The light should be lit.. What they have you do is remove the lock bolt, now while pushing the cable into the trans turn the adjuster counter clockwise as viewed from the front while still pushing in on the cable... Turn the adjuster till the test light goes out... Now still pushing in on the cable turn the adjuster clockwise.. Note which bolt hole is lined up when the light first comes on, now continue turning clockwise (and pushing) and count the bolt holes till the light goes out again... Now turn the adjuster back to the half way bolt hole... Put the lock bolt back in & re-connect the NSS wire... No loss of fluid, adjustment is perfect..

 

[dvw]

I've raced push button transmissions since 88. The most accurate way to adjust them is pan off. We have found incorrect or slightly bent rooster combs. Sloppy or incorrect cable ends. Incorrect neutral switches. If the adjustments off a little in a racecar it can cause plenty of wierd results. That's why I do them pan off. Not that big a deal. Drain the fluid in a clean pan and pour it back in.
Doug

 

[Van Stahr]

The way the service manual says to adjust the shift cable is shifter in Neutral, disconnect the wire going to the neutral safety switch, hook up a test light to the switch & the battery... The light should be lit.. What they have you do is remove the lock bolt, now while pushing the cable into the trans turn the adjuster counter clockwise as viewed from the front while still pushing in on the cable... Turn the adjuster till the test light goes out... Now still pushing in on the cable turn the adjuster clockwise.. Note which bolt hole is lined up when the light first comes on, now continue turning clockwise (and pushing) and count the bolt holes till the light goes out again... Now turn the adjuster back to the half way bolt hole... Put the lock bolt back in & re-connect the NSS wire... No loss of fluid, adjustment is perfect..

Thanks for the info.

When I tried this Monday the light never turned off even with the cable out, so, looks like I will have to take the pan off and see what's going on. I need a new park cable because it leaks and I have only found both as a set. I will get those pricy cables ordered and see if I can't get it all fixed at once.

Any one have recommendations on where they bought the shifter/parking cables?

 

[dvw]

You can repair the leaky cables with heat shrink tube. Done it many times.
Doug

 

[Van Stahr]

Here is an update.

I ordered new park and shift cables back on Black Friday. They arrived late January. Finally got a warm weekend with no rain last week and got the car up on my new hydraulic lift which made it a lot easier to replace the cables. I found that the bolt hole for the shift adjustment was stripped which is why it kept coming out of adjustment. Put a helicoil in it and got my wife to help me adjust the shift cable. So much easier to see what's going on with the pan off.

I am happy to say that it now shifts properly as well as no more transmission oil leaks from the cables or anywhere on the transmission.

Thanks for all the input from everyone.