727 hard shift from park to reverse

-
Zak

Zak

FABO Gold Member
FABO Gold Member
Joined
Jun 3, 2010
Messages
93
Reaction score
13
Location
Valdosta, Georgia
727 trans shift harsh from park to reverse. No other abnormalities. Other enthusiasts recommended starting in neutral which would allow fluid to fill up pump area quicker. Been doing that but still is a bit hard shift. I'm hearing it's a converter problem? Duster has stock converter. Appreciate any input/suggestions....
 
Sometimes builders replace the waved retainer ring in the front drum with a flat one to increase 2-3 shift firmness, but it creates a hard reverse engagement. Of course, if the direct clutch has any wear, it will engage hard, plus you'll lose third gear when it warms up on a hot day; but in that case, reverse would also be delayed. Not a converter problem.
 
CudaFactHackJob said:
Sometimes builders replace the waved retainer ring in the front drum with a flat one to increase 2-3 shift firmness, but it creates a hard reverse engagement. Of course, if the direct clutch has any wear, it will engage hard, plus you'll lose third gear when it warms up on a hot day; but in that case, reverse would also be delayed. Not a converter problem.
Click to expand...
Thanks bud
 
Yeah, rear band first. That is why it is called the low/reverse band.
 
Bewy said:
Yeah, rear band first. That is why it is called the low/reverse band.
Click to expand...

Yes check your low reverse band adjustment first. How many miles on the trans? Did this just start or something new? More information will be helpful.
 
In reverse, the front pump output is not regulated besides the hi-pressure relief valve.
To make reverse, the trans uses the Hi-drum and the L/R band.
As mentioned, the Hi-drum uses a wavy spring to cushion engagement.
The L/R servo uses a spring to slow it down.
Now it just so happens that the Accumulator spring is about the same size and fits in there very nicely......... but it is a far stiffer spring. If those two are swapped , Bam! as soon as the L/R servo sees pressure it instantly slams the band.

To make First gear, the trans uses two methods;
If you put it into Drive, the trans will engage the Forward clutch and use the rear Sprag to make sure the output shaft turns in the correct direction. The L/R band is not used.
In Manual Low. the L/R band is used again to anchor the business.
You can use this oddity to help diagnose the servo-spring.
If it shifts softly into Drive, then all is well. But
if it bangs into BOTH manual Low and Reverse, I would suspect the servo spring. Especially if grabbing Second is a lil mushy
 
Last edited:
Thank you all for enlightening me on the internal operation. I appreciate it fellas...
 
You must log in or register to reply here.
-

Back
Top