Idle in 'D' vs Reverse Question

[beanhead]

I'll try to explain bestest I can....at idle, shift into R, take foot off the brake, car moves with what feels like twice as much power as foot-off-the brake idle in D. It rolls a bit faster and the E-brake doesn't stop it; in D the car rolls slower. Normal? Or does the trans need some kind of adjustment? It was rebuilt approximately 5000 miles ago. Thanks!

 

[Sixpactogo]

Sounds like your Ebrake is not adjusted properly. The speed difference is because of the difference in gear ratio between the forward and reverse gears. I think it is all normal but you may need to adjust the Ebrake cable a bit.

 

[beanhead]

Sounds like your Ebrake is not adjusted properly. The speed difference is because of the difference in gear ratio between the forward and reverse gears. I think it is all normal but you may need to adjust the Ebrake cable a bit.

Okay, yeah I wasn't really worried about the e-brake part of it I figured that was just the brake itself. More interested in the differences in rolling speed, thank you!

 

[493 Mike]

When the valve body is in reverse the circuitry raises the line pressure which can cause this issue and there is no assist from the brake shoes as is designed in when applying brakes during forward wheel rotation.
Mike

 

[eldubb440]

reverse gear ratio different than 1st/low?

 

[493 Mike]

Yes. More leverage!
Mike

 

[wyrmrider]

The drum breaks have a cam self energizing feature going foreword
one gotcha is that in D you are on the sprag and in R on the Band
try manual Low- should be the same as D or you have a not likely sprag problem
I always use manual low starting up hills or towing

 

[Dipstick]

First gear 2.45:1, reverse 2.20:1 so, for the same engine rpm, reverse will go faster.

 

[beanhead]

Thanks for the info guys. Different ratio and line pressure, that explains it!