Diesel trucks Trans

[BIGNASTY]

Seems as thou Dodge isn't the only one that has a problem backing up a hill with an automatic transmission. A Ford had his smoking when he finally got into his camp spot. And the other day a Chevy had a problem (although not as big a problem) but had to give what sounded like a BUNCH of long peddle to get it to move the trailer backwards and a little up hill. What gives with this? something common to all Diesel PU trucks with autos?

 

[cerberusiam]

Reverse is a very unnatural gear in an auto, any auto. It requires a lot of redirection in the power flow and that robs a lot of the power. Couple that with high reverse ratios and it sucks with a heavy trailer.

Best thing one can do is go to low range if a 4x4. A 2x4 just has to live with it.

 

[BIGNASTY]

Thanks Cerb (aka Trans Yoda) it just seems kind of funny that the manufactures let this go, after all MOST buy these diesel trucks to tow and backing IS part of the process.

 

[cerberusiam]

Not much you can do with transmission that has multiple planetaries in it. You have to run the power thru 2 less than adequate leverage planetaries to do it. When they went to 3 pinions the ratio was better but still not what you get from a manual. Manual reverse is single use, and auto reverse is the combination of several forward gears run thru the planetaries that were designed for forward gears. The amount of power to reverse with less than adequate leverage makes it neccessary to use the throttle hard at times. Sloppy TC's dont work well in forward gears let alone reverse when there is no lockup.

With a 4x4 low range is your friend in reverse, most people just don't get the concept. A reverser box is about the only other way to do it with the size restrictions in an LD platform and that is $$ plus another lever for the monkeys to play with.

 

[NIsaacs]

Seems as thou Dodge isn't the only one that has a problem backing up a hill with an automatic

They are getting better.



Ford 5R110 (R) ratio 2. 88

Ford 6R140 (R) ratio 3. 13



Chevy Allison (R) ratio 5 or 6 spd 4. 49



Dodge 48RE (R) ratio 2. 21

Dodge 68RFE (R) ratio 4. 44

Dodge AS69RC (R) ratio 3. 54



Nick

 

[RustyJC]

Yep, I've had no problems backing my 16,000 GVWR 5th wheel with the 4. 10 gears and 4. 44:1 reverse ratio in the 68RFE plus the torque multiplication in the torque converter.

Rusty

 

[BIGNASTY]

yep, i've had no problems backing my 16,000 gvwr 5th wheel with the 4. 10 gears and 4. 44:1 reverse ratio in the 68rfe plus the torque multiplication in the torque converter.

Rusty

up hill????

 

[NIsaacs]

up hill????

Big,



Not using torque converter multiplier.....



Your stock pickup with 600 tq, 2. 21 ratio reverse gear and if you have a 4. 10 rear axle, your axle torque will be 5,436 lbs.



Rustys stock 650 tq, 4. 44 reverse gear ratio w/4. 10 gears will produce 11,830 lbs of axle torque, big difference.



Now for the 4x4 guys and a 2. 72 low range... ... their torque will be of the charts!



Nick

 

[BIGNASTY]

Big,

Not using torque converter multiplier.....

Your stock pickup with 600 tq, 2. 21 ratio reverse gear and if you have a 4. 10 rear axle, your axle torque will be 5,436 lbs.

Rustys stock 650 tq, 4. 44 reverse gear ratio w/4. 10 gears will produce 11,830 lbs of axle torque, big difference.

Now for the 4x4 guys and a 2. 72 low range... ... their torque will be of the charts!

Nick

Not arguing the fact's, all I know is mine is a POS when it comes to backing with a load. I really didn't realize how bad it was until I had our Gooseneck trailer loaded and tried to back up a little hill with it, Now I just make sure that I don't get myself into a predicament that requires backing with a load OF ANY KIND in my case. Something I just have to live with I guess. The Ford in the Post wasn't doing any better than I could have with my Dodge but at least mine wasn't smoking.

I still wouldn't trade my truck for anything EVEN IF I COULD BACK A LOAD :-laf

Been seeing lots of trucks with the hoods up on the road and in the gas stations of all brands and MOST ONLY A YEAR OF SO OLD.

 

[p-Bar]

I'm thinking on installing a browny box where the carrier bearing goes. It will give me a few more gears too