fresh 727 problem

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o1heavy

o1heavy

1974 dart sport
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Rebuilt my first 727 the trans has been working pretty good ,then after a few miles the trans would take a few seconds to actually drop into reverse after the shifter was put in gear , continued to run the trans went to the track made about 10 passes no problems loaded up and came home ,pulled it out of the shop a few days later and noticed than when driving under lite throttle it would flare up when shifting from second to 3rd ,I have the pan ,vb,and the rear servo out no problems found , just kinda looking for a little direction thanks sorry for the long post
 
What did the pump support and high gear clutch drum look like? Did you replace the busings throughout? What sealing rings did you use on that support (teflon or iron)?
 
The drums looked good used steel rings, the reverse problem has only been a issue since I rebuilt it ,I have had the trans a long time ,what is the benefit of a billit servo ,thinking I may put it back together ,install a temp gauge and figure out how to perform hydraulic pressure testing on it ,and make sure it is not getting hot ,I did install a b&m cooler with fan in the rear of the car during the rebuild , hopefully it is not a case or bushing problem.
 
A billet servo won;t distort or break under abuse. That's about it. The factory ones are pretty durable but it the line pressure's up there and you're racing it the billet ones will help. Search MRRANYJ on Moparts. He makes them.
Flaring is (in my experience anyway) a pressure problem rather than a shift timing problem. Make sure the 2nd gear band is ok and adjusted right for the servo lever used.
For the reverse issue - make sure the rear band and shifter itself are adjusted properly.
Low pressure will axasperate all those conditions - which is why I asked about the sealing.
You didn;t answer about the bushings - if they are worn the high gear clutch drum is allowed to wiggle and it can lose pressure at those sealing rings.
 
The pump bushing looked good but I didn't have a new one to compare it to the hub seamed to fit nicely ,really should have changed the bushing
 
if the vb is out, why not do an air check of the front clutch [high/reverse clutch by function] use a rubber tip air gun and apply 60 to 100 psi to the correct apply holes in the case, listen for the "air loss" if it is excessive, problems exist and the trans should be removed for further inspection. You can check all four components which control the three forward gears and reverse very easily. If you have a mopar manual, the holes will be clearly marked. Is this a reverse shift valve body?
 
Used a rubber tipped air blower to test the front and rear clutch drums,the rear clutches locked up nice but the front clutch would not lock up and air seemed to be leaking around the pump area but anyways guess she's got to come back out ,,, reverse and 3rd are on the front clutch pack right just checking , and could a worn bushings cause the leak , I remember testing before I put in the first time and it would lock up but seemed a little funny but I had nothing to compare it to
 
That explains the slow to engage reverse and the slight flare up when shifting into 3rd right ???
 
Correct...you can air check those drums right off the pump once you pull it.
Bore fit those rings in the drum make sure they fit snug in the Dir/ front drum also check the drum for ring wear.
Make sure the pump to stator bolts weren't left finger tight...and change those bushings. Make sure you take note of their depth before you knock out the old ones out so they go back to the correct depth. GL
 
kinda weird but this is what I founf
 

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Interlock ends broke off both stator rings?
Never seen that from running before, only on assembly.

How do they fit in the front drum bore?
 
Yes usually an assembly issue... don't feel bad many before you have done it.
Next time around cut the heads off a couple 5/16 bolts and make a couple studs as guides.
Lube the pump oring, sealing rings and case up and the pump will slide easier. Also if you have the band struts together back the band off some so the drum will have room to wiggle.
Measure the old sealing ring with a micrometer against the new sealing ring for width and thickness and if they're the same you'll be ok to reuse one of the old rings as long as it's not stepped on the inside.
Thats if you don't have access to a new sealing ring kit and don't feel like buying a complete seal and gasket set.
 
It hard to see in the picture but the rings are thin kinda look like a piston ring that has ingested dirty air for a while
 
Transmissions have to be pretty clean when assembled, and lack of assembly lube would contribute.
Paste the inside of both drums and the hub and rings with vaseline next time you put it in.

Notice how much assembly lube looks like red vaseline?
That's pretty much what it is, and it melts into the fluid when the trans is run.
 

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