??? on gearing in 68 duallie rear
 

What would the gearing be in a 68 chevy duallie rear end that would have been in a tow truck back then? Were there a lot of options or just a few?

Re: ??? on gearing in 68 duallie rear
 

4.10 or 4.56 most common

Re: ??? on gearing in 68 duallie rear
 

Most likely 5.13s

Re: ??? on gearing in 68 duallie rear
 

Are they replaceable?? More highway driving gears?

Re: ??? on gearing in 68 duallie rear
 

Tim has it right 5.14 with the HO72 & RO5 DRW option (9000 or 10000GVW). But if by some chance it has the 11K rear axle they would be 6.17s (14000 GVW). If you do have the HO72 then the 4.10s from a SRW pickup should drop right in and that is 20% right there unless you are running tiny tires too.

Re: ??? on gearing in 68 duallie rear
 

6:17's???? Good lord I bet the motors were screaming at 45 mph. But I also bet it sure would pull.

Re: ??? on gearing in 68 duallie rear
 

These rears are extremely easy to change ratio on. It's bolt-in. You pull the axle shafts back,disconnect the driveshaft,remove the entire differential assembly as a unit from the front,and reverse all steps. 4.10 is the tallest gearing you will get. My '92 K3500 has 4.10s with 5spd overdrive and it's perfect. Got grunt power,compression braking,and an excellent hiway machine. Actually,my '85 Jimmy is also 4.10 w/overdrive and an excellent hiway machine as well as great off road and towing. My '72 K2500 has 4.10s with no overdrive and it cruises just fine at 65. I used to drive them 75-80 all day long just fine. These days I am saving fuel at 60-65

Re: ??? on gearing in 68 duallie rear
 

The problem is this rear is in a 70 K20 pick up I'm looking at. Was installed 30 years ago so I don't know what wrecker type it came out of. Is the axle marked somewhere?

Re: ??? on gearing in 68 duallie rear
 

Here is an ID chart for '68.

Re: ??? on gearing in 68 duallie rear
 

My 69 wrecker has a factory 4.10. (thank God!) I'll let the 6.17's for you guys. :lol:

Heck, I put a 4.57 in my daily driver once and could actually watch the fuel gauge decline as I drove it! NO THANK YOU!!! :waah:

Re: ??? on gearing in 68 duallie rear
 

Now that I think about this, 6.17!

Geez, top speed in 1st with a 4.10 is about 5mph. What would a 6.17 do to that! :jdp:

Re: ??? on gearing in 68 duallie rear
 

My wrecker has 5.13s and it can comfortably pull 4th gear at 20-25. I can start in 3rd and it feels about how a three on the tree starts out. Starting in 2nd,I'm in 4th in about 60'. I have a 4.10/No-Spin for it,if I end up keeping it

Re: ??? on gearing in 68 duallie rear
 

This is a 350 4 bbl with a 3 speed auto trans. I will check for numbers.

Re: ??? on gearing in 68 duallie rear
 

I know we are talking about a 68 but my father-n-law says his 67 GMC with a 305 and 4-speed came out with what he calls highway gears new. He said that it is so high that he couldn't use it in the field farming. Although he did haul rock on it for a living for a while. So not sure what to think about it. Maybe he has the 4.10's

Re: ??? on gearing in 68 duallie rear
 

4.10 would be the hiway gears. I had a '70 CST/30 Custom Camper 157" cab & chassis that started life as a Winnebago RV. It had a TH400 and obviously was mean to travel the hiways. It had 4.10s. There were aftermarket ring & pinions available for a 3.90 ratio...big whoop! Not much change there.