Pulling just a 4 horse tr is not enough information to go on.I pull horse tr's,my show tr is a 3 horse with l-q and weighs in at 16500# loaded,my 4 hose with change room only weigh's in at 10,000# loaded,so you have to know what the wt of the tr is loaded.To pull the 4 horse loaded at 10,000# the 3.73 and 6spd is all you need,even to pull the 16,500# tr 3.73's with the 6spd would probably work,you would use 5th in the hills more over the 4.10,there are lot's of times that Iwished I had the 3.73's but ther are times I am glad that I have the 4.10's,I would not go auto if you are pulling heavy,I won't give up the Jacob e-brake.

 

I just pulled the new 5er 60 miles home from the dealer. The empty sticker weight is just short of 12K (should be between 14K and 15K once fully loaded). The 3.73 did the job.

If you have much more than that or you operate in an area with considerable grades, there is no question that I would opt for the 4.10.

I did not opt for the 4.10 because I will only be towing a dozen or so times a year and I will be towing just around the Midwest (ie no mountains). The off chance that I tackle a mountain, I would just take it a little slower and use 5th gear...

 

I've got a six speed with 4:10s but think 3:73s would be more usefull. You would just use 5th a little more.

Just my .02

 

I ditched my 4.10's for 3.55's so in your case 3.73s would be ideal with the 6spd. I like being able to pull up on any hill grab direct to keep the stress off of OD and still pull 60-65 mph at a decent rpm not rapped out. I hated my 4.10s for that reason. Also i noticed mileage changes across the board. Empty and loaded. I used to gross between 24k-30k lbs regularly about 300k miles worth and never had an OD problem

 

Personally...I think 3.73's are purrfect (at least with manual trans).

3.54 @ 70 mph = 2000 rpm
4.10 @ 70 mph = 2350 rpm
3.73 @ 70 mph = 2100 rpm

I run at 12k #'s routine...16K on occassion w 3.54's and it would be nice to be a shade higher in the band.

 

go with 3.73's... if backing the trailer is that bad, get a 2w-low kit

Forrest

 

I have 3:55s auto, stock tires 4x4 and the 2 wheel low range selector is the hot set up, like Forrest said, but I 'm not sure of the axel disconnect on newer trucks ...sty

 

I would go with the 3.73s. If the weight gets to where you would need the 4.10s, gear down when you tow on a grade. Otherwise you will have the 3.73 gears for solo use and save some MPGs. I had a '97 diesel with 3.55s with an auto tranny and my '02 had 3.73 with a 6 speed. . I have 3.73s with a 48RE now and tow a combo weight of just under 20K#. No trouble at all. My '02 towed the same weight with no trouble either. 3.73s will do the job for you.
Frank

 

I have a friend with a 2003 HO 48re 3.73 pulling a Big Sky 3575. He grosses just under 21K. I talked him out of 4.10's and he thanks me for that every trip. I don't know about the 6 speed, but you could not give me 4.10's. I have them in my 2000 CTD at work and it is too loud. Besides you can drop into drive on bad hills and run 70 with a 24V. I can run 65+ in drive without a GSK and pull anything the tranny will handle. He says the sweet spot on his truck is about 2000 rpm and that is the same for my 12V.