727A troubleshooting help...

[GassMann]

Hey all,

After a trans rebuild (full disclosure, first time I ever rebuilt a trans), I finally have my 66 Charger 440 running. I filled it, started the engine then, with the axle on jack stands, I cycled through the gears. Tires spin forward and reverse. Went through a few times. I put the tires on the ground, foot on the break and started it again.

Put it in reserve and I hear and feel it clunk into gear. Neutral, it drops out of gear. Drive and the trans clunks and wants to pull forward. Reverse and take my foot off the break. It wants to reverse but is not moving a lot. Drive... same thing... no really pull. Reverse, not even enough to move it out the garage. I am not REVING it but I am giving it enough that it should be moving.

During the rebuild, I replaced the forward and reverse clutches, the forward and reserve bands and forward spring plate and the forward and reverse planetary gears. I am sure I put all the bearings back where they belong in the valve body as well. I have a 19 spline input shaft and could not find a matching torque converter so I reinstalled my old one. I didn't realize 19s spline converters were not available and I didn't want to have to pull my trans apart again to replace the input shaft. It only had a few thousand miles on it when I stopped driving it in 92 so I thought "What the heck". Yes... I have owned this car since I was 16. I am coming up on 62 now so I know this car intimately.

I am fairly certain I adjusted the bands correctly but now I just don't know... it was my first time. I followed this old shop training video, which I thought was absolutely fantastic. and I followed the manual.

So where should I begin troubleshooting?

 

[Wietse]

Did you disassemble the valve body also? Added any shift kits or something?
Since the issue happens in forward and reverse it seems like a fundamental issue and not with a specific band or clutch.
It could be the Line pressure is set too low, not allowing any band or clutch to clamp properly.
Giving it throttle will increase the line pressure due to the throttle pressure which "boosts" the line pressure as intended to provide more clamping force on bands and clutches but this obviously is not ok to continue using as it will wear out everything very fast.
Apart from the adjustment, which could be set ok, there also could be a bad leak somewhere on the sealing rings.
I guess you will have a shop manual, have a read on how and where to check line pressure and see if it is in range.

Also note it is critical to ensure the throttle linkage is set up properly, this will not be the root cause of your current issue, but later on could give problems after solving the current one, just a heads up.

 

[dan juhasz]

did you bench check with compressed air all the clutch packs and recheck once installed in the housing through the passages.

 

[493 Mike]

You might just as well pull it out and tear it down. I assume you have a FSM and replaced all of the seal rings and seals? Was the valve body completely disassembled and cleaned? As previously mentioned, air check clutch pack and band operation and listen for air leaking. Keep asking questions here too.
Mike

 

[RemCharger]

Dumb question but did you recheck the fluid level

 

[GassMann]

did you bench check with compressed air all the clutch packs and recheck once installed in the housing through the passages.

Actually I did... it was part of the video and I applied air to watch the proper movement.

You might just as well pull it out and tear it down. I assume you have a FSM and replaced all of the seal rings and seals? Was the valve body completely disassembled and cleaned? As previously mentioned, air check clutch pack and band operation and listen for air leaking. Keep asking questions here too.
Mike

I did replace all seals. I tore down the valve body and thoroughly cleaned it. Could it be the torque converter? I emptied it of oil and didn't quite fill it back up before I put it in. It feels kind of like the converter is not doing it's job.

 

[Wietse]

The converter will fill once the engine is running and the transmission is in Drive, Neutral or Reverse.
Stock application has no oil flow going to the converter when in Park, you could try again selecting Neutral and let it run for some time to let the converter fill up before going to Drive or Reverse.
Since you already tried in Drive and Reverse, the converter would be full already as this only takes several seconds.

Did you set/adjust the Line pressure regulator as per instructions? (the one in the picture)

 

[MoparLeo]

Factory procedure is to make sure it is on a level surface.
Set parking brake. Start, let run at least 2 minutes. Run transmission selector through each gear for a few moments ending in neutral.
When at operating temp check level. Should be between 1 pint low and full. ATF+4 fluid.
Then do your other diagnostic checks.
Tom Hand Torque-flite manual highly recommended.

 

[Rebelrouser]

Hey all,

After a trans rebuild (full disclosure, first time I ever rebuilt a trans), I finally have my 66 Charger 440 running. I filled it, started the engine then, with the axle on jack stands, I cycled through the gears. Tires spin forward and reverse. Went through a few times. I put the tires on the ground, foot on the break and started it again.

Put it in reserve and I hear and feel it clunk into gear. Neutral, it drops out of gear. Drive and the trans clunks and wants to pull forward. Reverse and take my foot off the break. It wants to reverse but is not moving a lot. Drive... same thing... no really pull. Reverse, not even enough to move it out the garage. I am not REVING it but I am giving it enough that it should be moving.

During the rebuild, I replaced the forward and reverse clutches, the forward and reserve bands and forward spring plate and the forward and reverse planetary gears. I am sure I put all the bearings back where they belong in the valve body as well. I have a 19 spline input shaft and could not find a matching torque converter so I reinstalled my old one. I didn't realize 19s spline converters were not available and I didn't want to have to pull my trans apart again to replace the input shaft. It only had a few thousand miles on it when I stopped driving it in 92 so I thought "What the heck". Yes... I have owned this car since I was 16. I am coming up on 62 now so I know this car intimately.

I am fairly certain I adjusted the bands correctly but now I just don't know... it was my first time. I followed this old shop training video, which I thought was absolutely fantastic. and I followed the manual.

So where should I begin troubleshooting?

Put a pressure gauge on it. Chrysler did a good job gave pressure ports for every friction element. I have seen guys break the lugs off the front pump gear and it acts like you describe.
Are you positive you have enough fluid in it? complete rebuild with stock pan is 12 quarts to my memory.

 

[451Mopar]

It could be the converter too?
I had a broken 19-spline converter and no power to the input shaft.

The input spline count, pump, stator support, and front drum had 3 different versions I believe.
The 66 and earlier, the 67 to 70, and the 71 and later.
I forgot which year had the larger and smaller diameter input shaft, but they need the correct pump stator support to seal to.
Also need to check the input shaft and drivetrain end-play(s), and where the support sealing rings are setting inside the front drum.

 

[dvw]

It functioned before you disasembled it. So I'd assume the converter is OK. Make absolutly sure the fluid level is correct with dipstick tube fully seated into the trans case and the fluid being checked in N. After that if it doesn't move in any gear there is a lack of pressure. Put a gauge on it before you get to carried away. If it shows low pressure which I bet it will, then why? Reaction shaft support bolts loose, pump gear tabs broken, valve body screws loose, valve body itself is loose, cracked valve body, incorrectly assembled valve body. Missing/broken rings, clutch seals torn, band adjustments wouldn't result in a no drive condition in all gears.
Doug

 

[GassMann]

Wow guys... great info all. Lots to dig into.

 

[GassMann]

Factory procedure is to make sure it is on a level surface.
Set parking brake. Start, let run at least 2 minutes. Run transmission selector through each gear for a few moments ending in neutral.
When at operating temp check level. Should be between 1 pint low and full. ATF+4 fluid.
Then do your other diagnostic checks.
Tom Hand Torque-flite manual highly recommended.
View attachment 1511508

I just ordered this manual.

 

[GassMann]

Put a pressure gauge on it. Chrysler did a good job gave pressure ports for every friction element. I have seen guys break the lugs off the front pump gear and it acts like you describe.
Are you positive you have enough fluid in it? complete rebuild with stock pan is 12 quarts to my memory.

Where do I mount a pressure gauge?

 

[GassMann]

It could be the converter too?
I had a broken 19-spline converter and no power to the input shaft.

The input spline count, pump, stator support, and front drum had 3 different versions I believe.
The 66 and earlier, the 67 to 70, and the 71 and later.
I forgot which year had the larger and smaller diameter input shaft, but they need the correct pump stator support to seal to.
Also need to check the input shaft and drivetrain end-play(s), and where the support sealing rings are setting inside the front drum.

This transmission came off my 318. I got a BB housing from a friend, gutted the parts out of the original housing, replaced all the clutches and seals (from a kit) and installed it all in the larger housing. I didn't replace the input shaft or converter. The converter was part of the original 318 and worked prior to the rebuild. The entire thing sat, totally assembled, until 2017 when I started to tear it all down. So the converter and the input shaft are a match. at least a match that works together.

 

[GassMann]

It functioned before you disasembled it. So I'd assume the converter is OK. Make absolutly sure the fluid level is correct with dipstick tube fully seated into the trans case and the fluid being checked in N. After that if it doesn't move in any gear there is a lack of pressure. Put a gauge on it before you get to carried away. If it shows low pressure which I bet it will, then why? Reaction shaft support bolts loose, pump gear tabs broken, valve body screws loose, valve body itself is loose, cracked valve body, incorrectly assembled valve body. Missing/broken rings, clutch seals torn, band adjustments wouldn't result in a no drive condition in all gears.
Doug

Excellent guide here Doug. It gives me somethings to test. I am looking to how to put a pressure meter on a 727 now.

 

[Wietse]

Check Line pressure on the below point, use a 1/8" NPT adapter to connect a gauge and check.
Put the trans in Drive and firmly apply the brakes and slightly rev the engine rpm to 1000rpm and see how much pressure you are getting.

 

[GassMann]

Check Line pressure on the below point, use a 1/8" NPT adapter to connect a gauge and check.
Put the trans in Drive and firmly apply the brakes and slightly rev the engine rpm to 1000rpm and see how much pressure you are getting.

View attachment 1512052

Thanks Wietse... that saves a lot of time.

 

[Rishi]

I just ordered this manual.

Hah, So did I, yesterday. I found it for $35 shipped on Amazon.

 

[Fran Blacker]

Thanks Wietse... that saves a lot of time.

That's from Service Manual, you should have one. Here's the link Service Manuals – MyMopar