I have an 06 2500 6spd qc lb 4x4 with 4:10 gears. I am thinking about putting in 3:42 gears, and a dynatrac locking hub kit. I hope this combo could give me an extra 4 mpg. That would take me from 2000 rpm at 60 mph, to 1600 rpm at 60 mph. I would also have less rolling resistance. Anybody think this goal is ridiculous? Us highway boys need better fuel economy. I also tow an 11k travel trailer. I think the truck can do it, am I crazy? Has anybody else tried a combo like this?


06 ctd h.o. 2500 4x4 lb 6spd 4:10
99 ctd 2500 2wd

 

With the plan to tow that much weight I wouldn't do it...

The best option would be a GV, you would get the best hwy and towing rpms.

Also are you sure you have 4.10's? I was under the impression you could only get 4:10's on an auto in 06.. The G56 has a lower OD than the NV5600 so the rpms on a G56 and 3.73's are the same as a NV5600 and 4.10's.... With a G56 and 4.10's you would be at 2130 rpms at 60, and a G56 with 3.73's would be 1940... I could be wrong, just what I thought.

 

i thought 3.73 was the only option for a g56 in 06'

 

I am going to do the same thing except I am going with a EMS kit. If your towing heavy you can just go in fifth and leave 6th for flats and downhills. With that combo you should be going close to 58-60 in 5th at 2000. (which is where you want it anyhow).

You do already have 3.73 though not 4.10s. (I though the same thing when I bought mine and would do 63mph at 2000)

I am going to go one step further though and put 19.5s on mine. So i can do 73-75mph at 2000k.

Good luck and let us know how it goes.

 

If by GV you are referring to gearvendors, they will void the warranty of their product if you are doing any towing. Just something else to look into.

 

According to who??? GEAR VENDORS provides overdrive product to racing cars and trucks up to 2000hp and trucks towing heavy RV's up to 25,000lbs gcvw.

 

GV makes thouse for TOWING...... and racing. had one in my big block dart....... NP with any warrenty. when in doubt CALL GV

 

If I had a 6sp I would not hesitate to go with 3.42 gears. As said before just down shift if need be. It could take a while to pay for the dynatrac huds tho. I kinda like not having to get out and lock my hubs in and out.

 

I have heard guys have put the GV unit on and see about 2 MPG increase, have to balance that out with the $2750 cost. And have also heard that GV will not warranty the unit if it is used for towing, so you may want to check on that. Maybe write back on this thread and let us know about the warranty.

 

Recreational towing is one of its main uses... Now commercial towing is another thing.

 

Thank you everybody for the great information. I apologize for the rear gear ratio mistake The gear vendors is not attractive to me. That unit will lengthen the tranny. That would make the bad pinion angle we already have even worse. I also think the warranty police (hope) is not smart enough to notice the ratio change if I just change gears.

 

When I put an OD in my '94 Ram it's going to be a US Gear unit. I've heard the GV won't hold up to EB use. The US Gear is all gear driven; it has to be stronger than a planetary.

Nick

 

Planetary gears are pretty darn strong.... The US looks nice, and can be used in 4wd too..... Either option is a LONG ways off for me....



I still don't think I would want to tow 11K regularly with 3.42's.... But thats just me.