Has anyone gone to 3.73 final drive?

[NapaBavarian]

I'e been looking at the two options of 4.10 and 3.54, one is great on the highway, the other is best for everything else! Has anyone spent the money to move over to 3.73? It' a bit of an average closer to 3.54 with a little better pull out power.

Or, I could just keep 2 sets of axles around and swap as I felt like it?

I like the idea of aux overdrives, but I'm not sure what is available on the secondhand market and parts support now or in 5 to 10 years.

 

[Macrobb]

A couple of other options:
1. With a GearVendors Overdrive, parts will probably be available. They don't seem to be out of business or anything. Stuff is just... expensive.
2. You could run 3.55 gearing and two sets of tires - one normal size(for highway/cruising) and one smaller(for towing).
3. You could run 4.10 gearing and two sets of tires - one really large for cruising, one stock for towing.
4. If you've got a T19+4.10, you could simply go to a ZF5+4.10 - same towing performance, better cruising. Or go to ZF5+3.55 and have a nice overdrive... then bulletproof your IDI and run more power through it to compensate for the lack of gearing!

 

[jwalterus]

If I had a 2wd, it'd be a 6.9, t-19, Dana 70 3.73 rear when I was done with it............

 

[junk]

Ive run the numbers a bunch and the difference between 3.55 and 3.73 is like 5%ish. But 3.55 to 4.10 is like 15%. So if 3.55’s have you running 2200 rpm. 3.73 jump to 2311. And 4.10 to 2530. But the 4.10 gears should transmit more torque to the ground. Thus reducing strain on the drivetrain.

If i was to buy gears new for lite towing and general use. Id go 3.73. I think they are a great ratio.

I always run 238/85/16 tires. They’re easy to find around here.

 

[Pork_Chop50]

That is my plan to eventually ditch my 4.10s for 3.73. In Oregon our speed limits are topped out at 70 so I can hit that while spinning 2000 with 285/75r16 tires (theoretically). If I lived in a state that was higher limits I would likely do what @Macrobb said and run 3.55 with more power to compensate.

 

[HS108]

I looked into getting 3.73s for my truck, but the cost vs benefit was too high. I would never be able to drive enough to make up the cost in diesel.

 

[DaveBen]

All of my trucks were and are 4 wheel drives. @ diesel trucks and 4 gasoline trucks. All of them had 4:11 gears except for my current 2004 F-350 which has 3:73. I absolutely love the 3:73's.

 

[austin92]

I built a 10.25 for my 83 with 3.73s and a Detroit truetrac. Every time I tow I wish I had 4.10s but my 6.9 is na. It also has had a zf5 swapped in. Ideally I’d like to go 4.56 with a gear vendors + turbo. 3.73s are nice though. I can tow 70mph in 4th or 80 unloaded in 5th and still average 16+mpg. Im running 245/75r16 tires. If I had a turbo I’m sure 3.73 would be plenty but na I wish I had 4.10 when pulling much more than 5k. Not many here have 3.73s, I’m content but not impressed, ask what ever you want


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[towcat]

I built a 10.25 for my 83 with 3.73s and a Detroit truetrac. Every time I tow I wish I had 4.10s but my 6.9 is na. It also has had a zf5 swapped in. Ideally I’d like to go 4.56 with a gear vendors + turbo. 3.73s are nice though. I can tow 70mph in 4th or 80 unloaded in 5th and still average 16+mpg. Im running 245/75r16 tires. If I had a turbo I’m sure 3.73 would be plenty but na I wish I had 4.10 when pulling much more than 5k. Not many here have 3.73s, I’m content but not impressed, ask what ever you want


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finally.
someone who understands what really make these motors tick.
if you want to tow real loads, you need gearing.
it's that simple.

 

[Macrobb]

finally.
someone who understands what really make these motors tick.
if you want to tow real loads, you need gearing.
it's that simple.

... Or more power! Power solves all sorts of problems.

Honestly, N/A I'd want no less than 4.10 gearing - Once you double the HP with a turbo and fuel, well, it changes the game quite a bit as to what makes sense.

 

[frankenwrench]

My truck was 6.9 with the zf5 and I just found a 2001 superduty f250 with 3.73 and pulled the whole rear end and replaced hub seals gear oil and rotars and pads and everything was plug and play. And I love the gears with the modest 245, 85, r16 I have. Still pulls my smallish loads just fine and highway speeds are easy to attain. I also have an Ats 093 installed witch helps alot. Only issue is rotating tires due to the metric bolt pattern on rear and standard bolt pattern in front.