4.56 vs 4.10 Gears

[kblazer87]

Have you decided on the rest of the drivetrain yet? Stick or auto?

 

[Recovry4x4]

Not really Mike. I'm leaning towards the 465/Ranger combo with this and put the 700 in my flatbed project. Right now it will likely stay as is. I'd like to draw a fair comparison of the gears first.

 

[still standing still cyco]

I have a friend with an M1010 with 6.2 turbo'd, 5spd (i believe a 4500 but not positive), 4.10s, on 35s. He says it'll cruise at 70-75 no problem. I've been considering the 4.10 swap for my M1010 (currently all stock), but I think I'm going to wait until after I lift it and put 35-38" tires to see how the stock gears/motor pull it. Eventually it'll get repowered, (most likely with a mild sbc, maybe a 4bt). I'm undecided on the transmission tho. I want at least a 4spd auto, but I don't want to deal with needing a computer to control it. I like the idea of a 700r4, but they're reputation of failing in big truck applications worries me.

 

[4x4 Forever]

I changed the gears from 4.56 to 4.10 on my M1008. Did not loose towing and acceleration is about the same.
If you have a reason to change, I'd say go ahead. Mine had loose internals in the front and decided to do the swap when I rebuilt it.
Cost was about $1100 each end but included everything new inside.

 

[Recovry4x4]

Well, now to see how it drives. Needs all new rear brakes before it gets driven. I did an add a leaf and an EZ Inch from DIY4X and the tires clear the box cross member but I'll still do some clearancing.

 

[ken]

Kenny, I'm thinking of a 4.10 swap myself. How much road speed did you get out of these? Did you notice and loss in power? Is it worth it?

 

[The FLU farm]

Had an M1009 that I played around with different gearing, tires, and transmissions in. With a 700R4, 4.10s and 35-inch tires it was pretty much perfect, including for doing 70+ mph. Although, that was with a Banks turbo.
An Atlas II transfer case improved the slow poking aspect.

 

[Recovry4x4]

Squeaked about 6 mph more. I drive this truck 65-68 all day long now.

 

[ken]

Thanks for the reply, I'm wanting to hold 60MPH towing my tractor. Anything less and I'm taking a big chance of getting rearended.

 

[biggerhammertx]

I have a question about vehicle speed.

I have a 1993 NAVY C.U.C.V. 1 1/2 (not the original and not yet the CUCV II.)

6.2 Diesel with 4L80E Transmission with factory 4.56 gears on 285/75R-16 BFG All Terrains.

WHAT highway speed can I reasonable cruise without overspeeding the Diesel and doing damage?

I've been told to keep it at 55 - 60 max speed. Any insight and help is GREATLY appreciated.
Any Calculator that can help me figure it out?

BIGGER_HAMMER

 

[98G]

https://www.ringpinion.com/calculators/Calc_RPM.aspx

 

[biggerhammertx]

Thanks very much 98G.

Quick Question for anyone out there.

How do I find / who do I need to contact to find the Final Drive Ratio off 4th / OD on my 4L80E?

A general internet search gave .75 for the Final Drive - don't know if there is any variations off the "military" versions or not.

That Calculator is pretty amazing, because I've never run Mongo much more than 60 on fear of overspeeding the diesel.

If I can open up on the highway at 70 or so, life will be grand indeed!

Thank You again for the help!

BIGGERHAMMERTX