6.4 Hemi Gear Swap

[Bldrinker]

I tow a 14k lb 5th wheel and went 4.88s and it does pretty good now. I can run 60-65 usually without much trouble. I am in WV though so nothing is flat here. But when towing, 5.13 would be nice, but I love the 4.88s for just normal daily driving. I am running 34" tires on my stock 20" rims.

Below is a pic of my truck at 65 mph with the 4.88s in 5th to simulate towing.

View attachment 214667

Thank you. Very helpful.

 

[mtofell]

I started this thread a few years ago since my 6spd tranny SUCKS and I was looking to improve the low speed towing - mainly to be able to hold 2nd easier up winding hills while towing my 11K 5th wheel. To date I haven't done the swap just since I don't get out towing that much and am just to busy/lazy to be without my truck for a few days. Also, as the years tick by it seems throwing 2K into my truck for an optional upgrade isn't the smartest financial decision. I'm 6 years in and almost to 100K.

Anyway, I'm intrigued with all the discussion about RPMs in 4th/5th/6th gear while towing. Honestly, that never even entered my mind. RPMs while flying down the freeway at 80 (without a trailer) is a factor but I guess I don't think that I'd know (or care) about the difference if I were rolling along at 65 in 6th with 5.13 gears or 5th with 4.56 gears. If the RPMs are the same isn't the power the same? It seems each ratio might have its own "sweet spot" but the upper gears seem to be pretty close together so a different ratio could just be compensated for with a different gear. (which is basically my complaint with this tranny.... large gap at 1-2, tight spacing at 3-6)

I'm not a MPG micromanager at all.... especially these days with gas prices. Is this a MPG thing? Or, is there some other reason it matters what gear you're in while towing at a common speed like 65MPH?

 

[68PowerWagon]

I tow a 14k lb 5th wheel and went 4.88s and it does pretty good now. I can run 60-65 usually without much trouble. I am in WV though so nothing is flat here. But when towing, 5.13 would be nice, but I love the 4.88s for just normal daily driving. I am running 34" tires on my stock 20" rims.

Below is a pic of my truck at 65 mph with the 4.88s in 5th to simulate towing.

View attachment 214667

I see a problem here Mountain... there is too much dust on your steering column. We must drive about the same amount of miles per year. There is only a couple hundred miles difference on our trucks. I don't use that dash page but I like it as it shows trailer brake percentage. I usually run the page that gives me all the trucks temps including the tranny. I might toggle back & forth to this one now.

 

[Mountaineer83]

Yeah, I've neglected cleaning for a while! Unlike me too.

Usually when towing I will watch the temps screen as well. I was just empty driving there but snapped the shot for reference for anyone wanting gears. I set it to always show my tranny temp and stuff no matter the screen.

I love the customization of our screens. It's nice to be able to show exactly what you want.