Axle question

got my 80 4x4 chevy running again.

Been thinking about doing some work to the truck, but am wondering if it would be worth it.

Right now the truck has 2.73 gears in it. They are ok on the highway but suck for towing anything.

I managed to get a set of axles that have 3.73 gears in them.

Right now the truck runs about 2000 rpm at 65 with the 2.73 gears.

If I go with the 3.73's that puts it up to about 3000 rpm then.

I have been thinking if I go with the 3.73's I would upgrade from the 235/75/15 tires to either 31's or 235/85/16 (stock tire for 3/4 ton trucks).
That would take about 300 rpm off.

Another thing would be to go with a 700r4 od tranny which would put the rpms back to about 1900 rpm then, but I would have to buy one of those.

What do you guys think?

700r4 if you can swing it. They also have a lower first gear.

what are u going to tow???

3.73 with 31 10.50 15 will give you a 3.54---if u go up to 33's closer to 3.25's--then put the 700r4 in--u will need to shorten drivshaft and get the switch kits to make it operate correctly--it is an electric thing on the early one's--the later trans were/are computer controlled--mid to late 80's was the switch period--also need a bracket for your carb to hook up the tv cable(u want all the channels ,correct???---lol)

I have an 85 GMC with that tranny so I am told....500 and its yours

i will add that i knew of several guys that had the 700's that were not pleased and replaced the with 350's--they claimed they wouldn't hold up to loads

the 1 in Julie's 85 parisiene has been good--it got a whole lot better after i made the carb and tv bracket change--shifts at the correct spots and will squeal tires from a stop or a slow roll with just a tap on the pedal--i have been driving the "old fogey van" so long getting in her car is like getting in a race car these days for me

what i have been told is the seals and o-rings dry out real quick on the 700's when not in use

The 700s had some problems but th later ones were good and any good rebuild will fix most of the issues I'm told. You can bypass all the electronic stuff and put a manual switch on for the lockup. Same as most older od trannys, always shift down to D for towing and keep it cool, shouldn't have any problems.

I guess I would occasionally tow something like a car or a trailer with dirt gravel etc.

Looks like the consensus is to get a 700r4 then?

Wonder how much the th350 I have now is worth to sell or as a core.

The tranny right now is coupled to a np208 transfer case, since it came out a 87 burb that originally had the 700r4.