Hey all! Just joined, couple gearing questions for ya all.

[alienman]

Hey there, first off I have a 1981 Chevy 4X4 1/2 ton.  It has a 350 with edelbrock intake, mild cam, and runs strong to a th350 tranny, with a np208 transfer case.  I use to run 33 inch mudders but I have just started a business and need my truck to haul a 18 foot car hauler with a 3500 pound compact excavator plus attachements so I switched to some aluminum rims with 235\75\15  8 ply tires.  The truck has 2.73 gears in it and is just a dog down low.  Putting the smaller tires on helped some but I recently found out both the front and rear diffs need to be rebuilt so I am considering a gear change.  The truck is going to be getting a complete body work job soon as well so don't mind the rust in the pics. 

What would be the best gears for me to use?  And would I just need to swap the crown and pinion?  It has a 12 bolt rear and a 10 bolt front. 

Whats size of ring/pinion gears would i need, i see listings for 7.5 inch or 8.5 inch, I am new to regearing so any help or advice is appreciated.

Here is a pic with the 33s


And here with the new little tires.

[Blazin]

Hauling a small excavator, and needing new gears. I would swap in a 14 bolt in the rear and either swap in some matching gears up front or a Dana 44 to match the rear. You would be able to get pretty readily 4:10s and you would be able to step up to better brakes for the extra weight. I have hauled a small excavator with a 78 K 20 ton with 4:10s. They were adequate for pulling but it was also an SM456 trans My 75 K 20 with 4:56s was much better at pulling the weight and slowing it down, it too was an SM456 trans. My current 79 K 30 350 SM456 has 4:10s but I am planning on swapping the 4:56 axles out of my diesel parts truck soon. Less brake use then when hauling heavy loads. PS Welcome from New Hampshaa.

[alienman]

I never thought much about the braking issue, the trailer has electric brakes on both axles which really helps the stopping.  But if those ever failed it would be a long stop on the highway I would think.  I was trying to get away from going to a 3/4 ton or 1 ton axle because i just got those wheels and I really like them on the truck. 

[VileZambonie]

You can always sell the wheels but I would find a 14 bolt rear if you really intend pulling a ton of weight around. In the meantime if you're having a hard time moving around all that weight see how it does in 4WLow range. What trans dod you have?

[anesthes]

If you use 4low with the front hubs unlocked, is it safe on dry pavement?

-- Joe