Towing differential

[Philip Saran]

Pete,

It sounds like you could be just as happy with something like 3:73
or 4:10's at the most for your truck, but that would also mean regearing
the front differential at the same time, unless you pulled the front drive
shaft out and just ran the truck as a 2x4 instead of a 4x4.

I think going down to 3:55 may be too much of a loss of towing power
though.

Does someone else have a opinion??

[NovaMan]

I have a friend with a 14-bolt full floater rear with 4.10 gears, so I might swap that in. I'd just keep the t-case in 2H until I got around to changing the front gears. Or I might keep the 14-bolt semi floater and put 3.73s in it.

My immediate concern isn't gear ratio selection, but differential selection. Eaton posi or Detroit Locker? I need to start pricing things out so I can figure out if I can afford gears AND diffs, or just gears.

[james schaechter]

I had a 1985 Heavy 3/4 with 4.10s (2wd) and T-400 warmed up 350 and it towed an open like it wasn't there. I didn't get great mileage, but it didn't change much towing or not. If you have a deal on a 4.10, I would go for it. If you start buying stuff new parts , it gets pretty $$$. I am guessing you have a 4 speed with granny low then.
If you start changing a bunch of things, you might be better off looking for a different truck. I have had several stick shift 4x4 3/4 tons (mid 90s GM). You can find them priced right. My brother has my old 1997 truck and it is awesome. It is an ext cab vortec 350 5 speed with 3.73s. It still pulls our 24ft enclosed at times and pulls it no problem. It has over 200k on it. Original engine and we just replaced the clutch. If yo usold your truck and bought one of these, I bet it would only cost a couple thou different. I would tow in 4th at 55 mph and 5th at 65 mph or above.Make sure you look for the heavy 2500 so it has the good HD trans. the med duty one has a small clutch and an integral bellhousing. They also ride nicer with the independent front susp instead of the straight axle. It might be worth getting a calc out the $$$ and do some research. you might find some deals.
By the way, many of the 1/2 ton SUV types like a Yukon for example have the power. I have a friend who towed a 26 ft enclosed with one when we he first got back into racing. I was expecting probelms with braking or suspension. With load bars, it handled well, stopped well (4 wheel discs). the weak point was actually the pinion bearing. Not strong enough for the weight on a long tow and he knocked 2 of them out before he upgraded to a 3/4 ton. JIm.

[Chris1529]

I don't think I would worry too much about the differential as long as it is in good shape. I don't know too many people that run detroit locker on the street though. I towed an open trailer with a 1/2 ton Ford 4x4 (351W Automatic) with an 8.8" rear and stock limited slip. The pinion bearing eventually came out of it.
The rest of the parts looked like new.

[NovaMan]

Originally Posted by james schaechter

I had a 1985 Heavy 3/4 with 4.10s (2wd) and T-400 warmed up 350 and it towed an open like it wasn't there.

Cool. Did it have a 14-bolt full-floater or semi-floater?

Originally Posted by james schaechter

I am guessing you have a 4 speed with granny low then.

Yessir. With the 4.88 gears, the trans in Low, and the t-case in 4L, I could start the truck going, hop out and walk faster than it moves.