Originally Posted by mulepic

[sorry for the long post. Here's the summary: 4.56 gears all around improve mpg and drive-ability. Read on for details.]

This morning I had the chance to do my towing test w/ my 4000lbs camper. It's a 70 mile round trip route that is a gentle climb with a steep climb at the end. It's out and back. I filled up the tank right when I began the test.

This is the first time I did this test w/ the new 4.56 gears. It worked out better than I expected. The h2 no longer down shifts all the time to maintain speed. and I have plenty of power between 65-70mph in 5th gear going up the gently climb. In fact on the way back I spent most of the time in 6th gear which is a first. If you read my earlier posts, 6th gear was completely out of the question while towing. Best of all when the steep climb at the end I could hold 65mph in 4th gear which happens at about 3200rpm's which seems about right for short stints (5-8 miles)

In the end the mpg blew my mind. Our 7.3l diesel Excursion (the h2 replaced) did the same test at 9.6mpg and the H2 did it at 8.5mpg with the original 3.73 gears. This test w/ the 4.56 gears matched the Excursion at 9.6mpg. I actually didn't believe it. So I filled the tank back up when I returned and only 7 gallons were put back in for the 70 mile test. Yes, that's 10mpg while towing. But since I've always uses the dash display, I'm going with 9.6mpg.

I couldn't be happier w/ the 4.56 choice. The H2 no longer constantly down shifts and has power at the mph I like to tow at.

There was a question about 4.88's. My only concern with those would be the gear strength i.e. smaller pinion and ring gear teeth. But if I only had to choose between 4.10's and 4.88's, I'd go w/ 4.88's.

Originally Posted by Baldfox

Forgive the silly question, but if you're getting better MPG, despite the revs being slightly higher (if i've understood correctly), what's the drawback ? Have you lost much low end grunt ? I guess the whole notion of regearing just not sitting that comfortably with me (or it's a brain fart!).

Originally Posted by H2CANEPADESIGN

Tow a 7k trailer as often as I can go camping. I have the stock 4.10 gears with 35" BFG KO2. My Deuce is an 03' so I just put it in 3rd gear and go unless it's going to be all flatland (which is rare here). Oh yeah, Magnusson Supercharger. works great. I tow in 3rd to keep the trans temps down. seems to circulate the fluid faster.