Our tow vehicle is a 2004 f350 with the v10 and 3.73 gears. It pulls just fine here in flat-land country, but not much of a grade is needed to make it shift down. We'll be heading out West in the near future and I don't think we'd do well in the mountains. The question is what gear ratio is needed to pull our 10,000lb 5er in the Rockies?

A super charger would be best option imho!But with this in mind. probably something in the 4/33 or 4/56 range. And even then, what you have will work. You will be in a lower gear than the ratio's mentioned. You will get the job done. Most of us that have pulled at 8k+ feet with gas rigs, have had to rev the motors more than we do in my case, sea level to get the power to do what needs doing. As you lose 2-3% of HP per 1000' above sea level that you are. So at 8k', you are down some 16-24%! Hence why a super charger might also be the what you want. It compensates for the most part for the lower air density.For a single trip.....reality, just go with what you have! Save the money spent on these items you in reality will probably not need.Marty

I had a 2008 F350 hauling a 36ft Mobile Suites with V10 and 4:30 gears and it was a comfortable tow in all terrain. That would be an easy swap in your case. Just remember that V10 is a small block and likes to rev. Often held a long steep grade and 4500-5000 rpm and did the job.

JMHO but I see it is a 4x4. You'll need to change out front and rear. You'll be a little slower on the grades with your present 373. I wouldn't worry much for one trip.

Personally, I would not change the differentials (you are aware, I hope, that you have to change BOTH of them on a 4X4!). That 2 or 3 thousand dollars would be very nice to have on the trip!You should be fine with your 3.73 ratios. I towed over the major mountain passes (on I-90, I-80, and I-15) in the Northwest with a 1994 Dodge 3500 CTD with a 4.10 ratio rear end. I still had to shift down frequently. My son towed the same trailer over some of the same passes with a 3/4 ton Dodge with 3.54 gearing, shifting frequently.Shifting gears is a fact of life when towing in the mountains. There is no gearing that will get over Lookout or Snoqualmie without shifting!Have a good trip.For comparison, I drove a 2 1/2 ton truck over a pass in Hawaii, with 1200 gallons of Avgas aboard, with 5.88 gears, and still had to shift down frequently.

Stick with what you have and just be paitient. You'll be fine. It's not worth the cost...

Differential swap | Good Sam Community

62 Replies

Jack_Diane_Free
Explorer
Sep 15, 2015
I had a 2008 F350 hauling a 36ft Mobile Suites with V10 and 4:30 gears and it was a comfortable tow in all terrain. That would be an easy swap in your case. Just remember that V10 is a small block and likes to rev. Often held a long steep grade and 4500-5000 rpm and did the job.
blt2ski
Moderator
Sep 15, 2015
A super charger would be best option imho!

But with this in mind. probably something in the 4/33 or 4/56 range. And even then, what you have will work. You will be in a lower gear than the ratio's mentioned. You will get the job done. Most of us that have pulled at 8k+ feet with gas rigs, have had to rev the motors more than we do in my case, sea level to get the power to do what needs doing. As you lose 2-3% of HP per 1000' above sea level that you are. So at 8k', you are down some 16-24%! Hence why a super charger might also be the what you want. It compensates for the most part for the lower air density.

For a single trip.....reality, just go with what you have! Save the money spent on these items you in reality will probably not need.

Marty

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Differential swap

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