Decision 4;56 or 4:88

[CincyCuda68]

‘18 2500 6.4 with 3:73
37” tires and 6” lift.
Towing 36’ toy hauler.

Which way do I go and what is the effect on highway speeds? I rarely go over 75 and don’t want to completely kill the whopping 13 mpg for regular (non towing) driving.

7792C4AB-37FF-4265-8230-D478320B1217

• CincyCuda68
• May 18, 2021

 

[chris1126]

i did 456 with 37s and towed my camper and it did fine. plenty of people will tell you 488 and i cant disagree, but 456 will do the job.

 

[chris1126]

p.s....dont buy nitro gears

 

[crash68]

^^^ what he said.
If your truck had factory 33" tires, then going to 4.10 would bring you back to original rpm. Dropping to 4.56 would be equivalent of having 4.10 on the factory 33" tires.

3.73 gear at 75mph on 33" 1760 rpm
4.10 gear at 75mph on 37" 1750 rpm
4.56 gear at 75mph on 37" 1950 rpm
4.88 gear at 75mph on 37" 2100 rpm

 

[CincyCuda68]

i did 456 with 37s and towed my camper and it did fine. plenty of people will tell you 488 and i cant disagree, but 456 will do the job.

Did you go with Yukon?

 

[CincyCuda68]

^^^ what he said.
If your truck had factory 33" tires, then going to 4.10 would bring you back to original rpm. Dropping to 4.56 would be equivalent of having 4.10 on the factory 33" tires.

3.73 gear at 75mph on 33" 1760 rpm
4.10 gear at 75mph on 37" 1750 rpm
4.56 gear at 75mph on 37" 1950 rpm
4.88 gear at 75mph on 37" 2100 rpm

Still a tough decision. Only 150 RPM difference between the two. Toy hauler is about 11,000 fully loaded. I did take it over the Rocky Mts with the 3:73 but it wasn’t fun. I suppose either ratio would be a huge improvement.

 

[crash68]

I suppose either ratio would be a huge improvement.

Base the decision on how you use the truck. If your mostly stop-n-go and/or towing over the mountains then go with the lower 4.88
If most of your travels are long(er) strechs and where you tow is mostly flat then go 4.56

 

[Daw14]

You will be happier with the 488s.

 

[CincyCuda68]

You will be happier with the 488s.

think that’s where I’m going. Not much rpm difference between the two.

 

[chris1126]

Did you go with Yukon?

no, nitro and their service sucked

 

[CincyCuda68]

no, nitro and their service sucked

Sorry to hear that.

 

[89grand]

I have Nitro 4.10's in my TJ Wrangler. They're dead quiet and no problems at all. Maybe different applications are better than some others, who knows.

 

[chris1126]

I have Nitro 4.10's in my TJ Wrangler. They're dead quiet and no problems at all. Maybe different applications are better than some others, who knows.

i have no issues w the gears now. the customer service is **** poor and they lie! there was a flaw in them. not just mine, years worth of flaws. my shop found it, they admitted to it and said they had the design sent to china to get them resolved. their website says "made in usa" buncha liars. plus my shop had to work them so they didnt fail potentially. stay away from nitro! trust me.

 

[89grand]

I can't stay away from them, as they were installed about 2 years ago, but yeah, if some of the gears are junk like for our trucks, that's a good idea I suppose.

 

[ram1500rsm]

Don't fear the gear, especially if you have the 6 speed trans.