comments on 4.56 gear changeover

[Randy DeBaillie]

I have a 06 3500 srw quad longbed, 4x4, with 3. 73 gears. The truck weighs 10,000 pounds with tools, aux fuel tank, and compressor. I use the truck for farming and regularly gross 26000 pulling various trailers. The truck rarely sees highspeed interstate driving. The truck takes a lot of thottle to launch (it's an automatic) , especially in soft ground. After completing this years planting season I decided it was time to take action. My choice was 4. 56 gears, 4. 10 wasn't low enough to justify the cost to change. I'm very pleased with the results. It now shifts into lock up at 41mph instead of 49 mph. At highwaty speed, 60 mph = 1980 rpm instead of 1620 rpm, much better suited forpulling in overdrive. It's amazing the difference when starting the load rolling, almost like shifting into low 4wd. Also a suprise, the speedometer is still correct, must pick up wheel speed at the outer sensors.

 

[macdaddy]

Is it safe to say you have stock tires and rims/, sure sounds like it. The numbers you mention with respect to RPM's sound like mine 63 mph @ 2K. You are right in making a point about getting a load up and moving. I really don't even pull very much with mine but would still go for the lower gearing.



Unless your planning on driving over the speed limit while towing/hauling the lower gearing puts the CTD right in the sweet spot for fuel economy as well as a safe speed from which to bring the lash up safely to a stop.



Mac

 

[HBarlow]

Thanks for an excellent post.

Your experience supports the advice some of us always give about avoiding a truck with 3. 73 gearing if it will be used for towing.

Many argue that their truck pulls fine with 3. 73 gears. It is true that the Cummins engine call pull the load but your story demonstrates why 3. 73 gearing is a bad choice.

 

[MAshley]

Thanks for an excellent post.



Your experience supports the advice some of us always give about avoiding a truck with 3. 73 gearing if it will be used for towing.



Many argue that their truck pulls fine with 3. 73 gears. It is true that the Cummins engine call pull the load but your story demonstrates why 3. 73 gearing is a bad choice.

I would like to mention that maybe this is the case with Automatic transmissions more then the manual... . As I couldn't really deal with a lower rear end



I have a Manual 06 3500 and have towed about 70K miles at 25,000 GCVW 92K on the truck now, and have no complaints. Also in reviewing the original post a G56 manual 3. 73 gears runs about 1900 1950 RPM at 60 MPH so it seems the auto has a nice Highway Over drive gear that the manual guys never see. I have heard of a change in 6th gear . . I don't have that option.



Please someone correct me if Im wrong but the G56 transmission and 3. 73 gear is the same as a NV4500 NV4600 with a 4. 10 rear end. which would be really close to "Randy's" outcome.

 

[AABEN]

I run 3. 73 gears and they do me a very good job. All of mine driving is hi way driving. My weight is 23. 000+ . I run the mountains out west and took Interstate 8 in to CAL. And that is one good pull. That is where the JAKE payed for it self. So if you are going to run Hi Ways 90% of the time 3. 73 is not a bad gear. But the 4. 10 would had been good for Interstate 8.