4.56 vs 4.88?

[2018_ram]

I have a 2018 ram 3500 4x4 6.4 hemi I’m planning on regearing my truck and wondering what gears I should go with? I tow 5th wheel camper. I have 3.73 right now. The people that have those type of gears what kind of rpms are you running at 60 mph?

 

[DILLIGAF]

 

[Mountaineer83]

I had the 4.10 factory and went to 4.88 Yukons. Almost went 5.13 because of my 5th wheel. I am running 275/65/20 tires and at 65mph I'm about 2600 rpm in 5th while towing.

In 6th at 60mph I'm tight at 2000 rpm. My mileage didn't change a whole lot because it doesn't work as hard now. It's is an absolute pleasure to drive. The guy who installed mine drive a Cummins and he was super impressed with the new drivability of my truck.

 

[Bldrinker]

I had 4:10. Went to 4:88.
I have 285/75/18 tires. Trailer is 37’ long 10k dry 14k loaded.

if you are keeping stock tire size go 4:56.
If your trailer is under 10k leave truck alone.

 

[RLJ10X]

I love it when my tac needle is above 2000 rpm; So does my engine.

Let that Hemi turn.

 

[VernDiesel]

The mechanics at Tire Star truck shop were talking about this the other day. Their consensus was 6 speed go to 4.88, 8 speed stay with the factory 4.10s. Being the extra lower gears and better gear spacing made up the difference. I tow daily with a tuned ecodiesel 3.92 8 speed. I've thought even with more torque and at lower rpm than the 6.4 that it would benefit from 4.10s IE a little lower gear. Mountaineers post and my experience seem to confirm what the mechanics at the truck shop were saying.

 

[68PowerWagon]

I would say either will do you fine. I went with the 4.56 & stock tires. At 70mph I am right at 2,000 rpm's. My trailer is 13,500 all loaded up & the re-gear made a great difference in how it pulled & frankly drove as a daily driver. If I didn't average 16-17,000 miles a year I think I would have went ahead & went with the 4.88's.

 

[GsRAM]

I would say either will do you fine. I went with the 4.56 & stock tires. At 70mph I am right at 2,000 rpm's. My trailer is 13,500 all loaded up & the re-gear made a great difference in how it pulled & frankly drove as a daily driver. If I didn't average 16-17,000 miles a year I think I would have went ahead & went with the 4.88's.

Question Sir....If you use two haul, does it lock out 6th gear? If it does, what rpm are you turning at 65 which is the max I do when towing.

2k rpm isn't bad at 70 as I rarely exceed 75 even on the highway.

My 17 just turned 14,500 miles this weekend, so I'm considering committing to keeping it for a long time...and maybe try to keep it another 13 yrs.and then going to a 3500 before I retire.


Its garaged and not driven in the snow and with my OCD maintenance, still looks new.

If I do, I will seriously consider a regear. Thanks

 

[62Blazer]

The mechanics at Tire Star truck shop were talking about this the other day. Their consensus was 6 speed go to 4.88, 8 speed stay with the factory 4.10s. Being the extra lower gears and better gear spacing made up the difference. I tow daily with a tuned ecodiesel 3.92 8 speed. I've thought even with more torque and at lower rpm than the 6.4 that it would benefit from 4.10s. Mountaineers post and my experience seem to confirm what the mechanics at the truck shop were saying.

Not sure I agree with that. IMO adjusting axle gearing for towing is mainly for highway driving and not taking off from a stop. If you look at the top three gear ratios (4,5,6 for the 6 speed and 6,7,8 for the 8 speed) that you are mainly using on the freeway they are basically identical. The only big advantage the 8 speed has is a lower 1st gear, but you are rarely in 1st gear if you are towing down the road.

 

[VernDiesel]

Thinking about it I get your point. If you tow in the plains of the midwest than I would agree that it's mostly about the top 3 gears. If you are towing in the mountains or where you vary your speed a lot even in town where you have to deal with start stop start stop. Then how well the 6 speed handles 2nd & 3rd vs the 8 speed dividing it up between 2nd 3rd & 4th to always be in the right gear / powerband at the right time. I can see where the 8 speed would work great with 4.10 where as the 6 speed would benefit from the lower gear.

Guys who have towed with the same truck same motor and both the 6 and the 8 speed will tell you the 8 speed is a lot better to tow with. The guys that complain about the 6 speed gear spacing and rave about the 8 speed are often towing a big TT on mountain roads & switchbacks. So yea not so different the 6 & 8 speed on a flat at 55 or 65 like you say but add in some hills wind switchbacks and you will like the 8 speed much better. So much better that you may not feel the need to drop as much gear to optimise it depending on where you are towing and what you are towing.

 

[Bldrinker]

Stock tires go 4:56.

34’s or 35’s 4:88

37’s 5:13 ( you should have got a diesel)