Transmission acting up

Reece Stephens

New Member
Joined
Jun 10, 2020
Messages
46
Reaction score
20
Location
Lima, Ohio
My 727 has been acting up, it worked fine all day then all of the sudden it dropped reverse and all forward gears, after being turned off for 5 minutes it started moving under it's own power for about a quarter mile then stopped again. The fluid is new, the level is good, no leaks, throttle kickdown is properly adjusted, only 214 miles on the rebuild and the pump was replaced during the rebuild. The pump only makes noise after it stops moving and this has me scratching my head. Has anyone else had this issue?

Update- I pulled the pan, and the fluid was full of glitter, and the bottom of the pan is coated in metal.
 
Last edited:
Simple stuff first... Checked level in neutral with engine running? Correct?
 
Pull off the pan and check to see if the filter is still secured. If it is you will likely have to pull it out again.
 
The pump only makes noise after it stops moving

Pump shouldn't make any noise.

One thing comes to mind since the pump is noisy, although I would have expected either early failure or no go from the start. Was the convertor completely seated back in and fully engaging the pump when the trans was installed?

You could drop the pan and make sure the everything looks OK. Filter in place and I have seen valve body bolts not completely tightened, so a quick check wouldn't hurt.

If there was any kind of warranty on the trans, I'd be calling the builder before you got into it too far though. Perhaps before you even drop the pan.
 
Pump shouldn't make any noise.

One thing comes to mind since the pump is noisy, although I would have expected either early failure or no go from the start. Was the convertor completely seated back in and fully engaging the pump when the trans was installed?

You could drop the pan and make sure the everything looks OK. Filter in place and I have seen valve body bolts not completely tightened, so a quick check wouldn't hurt.

If there was any kind of warranty on the trans, I'd be calling the builder before you got into it too far though. Perhaps before you even drop the pan.
The converter is fully seated, the pump only makes noise in reverse, I haven't pulled the pan off yet that's tomorrow's project.
 
If you are getting a buzzing noise from the pump, that is often an indication of a suction leak. As noted, check the filter and the valve body bolts. If you are getting a grinding noise, the pump has probably failed. If this transmission has a warranty, take it back to whoever rebuilt it and make it their problem. I would not pull the pan in that case as that could void the warranty.

Dave
 
If you are getting a buzzing noise from the pump, that is often an indication of a suction leak. As noted, check the filter and the valve body bolts. If you are getting a grinding noise, the pump has probably failed. If this transmission has a warranty, take it back to whoever rebuilt it and make it their problem. I would not pull the pan in that case as that could void the warranty.

Dave
I rebuilt the transmission to spec using a Fatsco manual and rebuild kit, so no warranty
 
G'Day People,
Don't mean to Add to this Gentleman's Woes AND I Ain't No Expert.
But One Thing I do Know is, as Mentioned, If You are Going to Rebuild Your Own Trans, or Even Just Fit the Trans to the Vehicle, Make Sure the Converter is Properly Seated. If It's Not, Then the Very First Turn of the Key It Will Tear the Guts Out of the Pump AND You Start All Over Again.
I Can Remember Many Years Ago When I was in the Wrecking Game how many times I had to advise Customers they had No Warranty Simply because they had used
their Old Torque Converter in My S/H Transmission. (Too Lazy to Pull the Old one off the Motor.) We Always Supplied Trans & Converter Together.
If Your Trans is Blown it Most Likely has Filled the T/C with Shrapnel. You Bolt another Trans up & the Moment you Start it Up, You Fill the New Trans with All the Crap.
Another Trick was with Ford Owners. In the Land of OZ Ford used Borg Warner Autos behind the 6 Cyl Cars for a Lot of Years. I Remember One Fellow Complaining
about a S/H Trans not Working Properly. When we checked it out He hadn't Connected the Kick Down Cable. Absolutely Essential with a B/Warner as You only had to Drive a few Miles to Stuff the Trans Completely.
Another Sad Case I can Remember was a Customer buying a Ford 351 Cleveland Engine from us. Took it Home & Fitted it.
Bought the Exchange Motor back a Few Days Later and Mentioned that the Vehicle was Still Blowing Smoke.
We suggested He Drive it for Another Week or So as the Exhaust System was More than Likely Still Full of Oil if his Old Engine was as Bad as he had Described.
Week later he came to see us still with Problem.
Told Him to Leave the Car with us, A Couple of Hours Later Our Mechanic Tells us There's Nothing Wrong with the Motor the C4 Trans has a Blown Modulator Valve.
Apparently When this Valve Fails it Allows Auto Trans Fluid to be Sucked into the Carburettor.
The Customer had Never Mentioned that the Smoke the Car was Blowing was White NOT Blue.
The Poor Bloke had Gone to all the Work & Expense of replacing his Motor when all that needed doing was to Replace the Modulator, a Relatively Simple & Inexpensive Job.
O.K. Fellas I'm sure Most of You on this Forum have come to Realise I Like to Waffle, However the Point I'm Trying to get across is that if you Don't REALLY Know What you're Doing,
THIS IS THE PLACE TO ASK!
I Love Coming Here, I'm an OLD GEEZER But I Learn Something New Just about Every time I Tune In.
This Forum was designed for MOPAR Lovers to Help Each Other, That is One of It's MAIN FUNCTIONS. (Apart from Giving Each Other Cheek, Of Course. LOL)
One Last Piece of Advice.
We All Like to Save Money,(It has been known to Take Chloroform & Forceps to Get 2/- out of Me. LOL) But Sometimes Things Should Just be Left to the Experts.
Quicker, Less Aggravation & in the Long Run as Most Grandpas Know, It's So Much Easier When Things Get POOPY to be Able to Hand it Back to Some One Else to Fix.
Tony.M
 
I would do a line pressure check. If you don't have line pressure or extremely low pressure it is a possible pump or feed problem. No movement at all should not be a problem with any specific clutch or band because in reverse the front clutch and low reverse band is applied. In manual low the rear clutch and low reverse band is applied, however the if the low reverse band is bad you should still have first gear because the overrunning clutch should still hold first gear. Because you said it worked 214 miles I would assume your VB in assembled correctly. If the fluid is cold it is thicker so you get some movement when the temp comes up the fluid thins out and you loose movement so I'm sure you have a pressure problem.

My mental check list is like this:
No movement at all = line pressure problem. Could be pump, filter, VB .....
No Forward Gears but reverse works = Rear clutch problem
No Reverse but forward gears work = Low/Rev band problem
No Reverse, no 3rd gear = Direct clutch problem
No 2nd but first and reverse work = Front band problem

I have seen the filter get plugged up after a rebuild if the converter isn't replaced or the line and cooler isn't flushed. This usually causes the reverse of your problem it will not work correctly when cold but after worming up it works better.
I have also seen guys think they have the converter seated and isn't and when bolting the trans put it damages the pump gear tabs and doesn't work at all or works for a short time until the pump gear loosens up on the converter hub and fails.

I have rebuilt many 727's and 904's for street and strip and I'm in lower MI not far from Lima so if you need, I can help.
 
I would do a line pressure check. If you don't have line pressure or extremely low pressure it is a possible pump or feed problem. No movement at all should not be a problem with any specific clutch or band because in reverse the front clutch and low reverse band is applied. In manual low the rear clutch and low reverse band is applied, however the if the low reverse band is bad you should still have first gear because the overrunning clutch should still hold first gear. Because you said it worked 214 miles I would assume your VB in assembled correctly. If the fluid is cold it is thicker so you get some movement when the temp comes up the fluid thins out and you loose movement so I'm sure you have a pressure problem.

My mental check list is like this:
No movement at all = line pressure problem. Could be pump, filter, VB .....
No Forward Gears but reverse works = Rear clutch problem
No Reverse but forward gears work = Low/Rev band problem
No Reverse, no 3rd gear = Direct clutch problem
No 2nd but first and reverse work = Front band problem

I have seen the filter get plugged up after a rebuild if the converter isn't replaced or the line and cooler isn't flushed. This usually causes the reverse of your problem it will not work correctly when cold but after worming up it works better.
I have also seen guys think they have the converter seated and isn't and when bolting the trans put it damages the pump gear tabs and doesn't work at all or works for a short time until the pump gear loosens up on the converter hub and fails.

I have rebuilt many 727's and 904's for street and strip and I'm in lower MI not far from Lima so if you need, I can help.
I recently readjusted the low/reverse band, I haven't pulled the pan off yet, I'll be doing that later today. That'll determine what I did next
 
When you rebuilt the trans did you do a VB "shift kit"?

Also where did you set the line pressure adjustment?

When you bolted the engine and trans together are you sure you seated the TC all the way?
 
When you rebuilt the trans did you do a VB "shift kit"?

Also where did you set the line pressure adjustment?

When you bolted the engine and trans together are you sure you seated the TC all the way?
Torque converter was seated all the way, I had put a shift kit in the original valve body but it didn't shift right, so I swapped in another valve body that was completely stock and that solved the issue
 
Did you torques the VB bolts or just use the old German torque spec "goodntight"? LOL

Did you use a straight edge on the trans where the VB bolts up to see if it was flat? I usually gently run a file over the bolt holes and about 1 out of 10 times the bolt holes are a little high because someone over torqued them.

I have seen pulled bolt holes cause leakage leading to trans failure.
 
Did you torques the VB bolts or just use the old German torque spec "goodntight"? LOL

Did you use a straight edge on the trans where the VB bolts up to see if it was flat? I usually gently run a file over the bolt holes and about 1 out of 10 times the bolt holes are a little high because someone over torqued them.

I have seen pulled bolt holes cause leakage leading to trans failure.
I went by the specified torque in the service manual which was newton meters and tightened the valve body in the correct sequence
 
I went by the specified torque in the service manual which was newton meters and tightened the valve body in the correct sequence

Ok that's good. Do you have a pressure gauge that you can use to check line pressure? If you do I can explain the best way to do it and what kind of pressure you should be seeing. If you don't have one you should be able to rent one from a local parts store.
upload_2021-4-9_18-14-32.jpeg
 
Last edited:
Back
Top