[kgeorge]

I am thinking of replacing my 03 F-250 with a F-350 dually. My new fifth wheel seems just a little to heavy for my F-250. The 373 gears seem to pull even in mountains ok but with the tow boss option it seems you would be really turning some high rpms at 60-65 mph. Can anybody with the tow boss tell me what rpms you are turning at freeway speeds.

 

[SmokeyWren]

If my math is right, pick any speed you prefer and multiply by 33.2 and that will be real close to the engine RPM with a 4.3 rear end and stock-size tires.

55 MPH times 33.2 = about 1,825 RPM

60 MPH times 33.2 = about 1,990 RPM

65 MPH times 33.2 = about 2,160 RPM

70 MPH times 33.2 = about 2,325 RPM (vs. 2,000 RPM with a 3.73 or 2,200 RPM with a 4.10)

75 MPH times 33.2 = about 2,490

80 MPH times 33.2 = about 2,655

Although your actual red line is higher, I like to use 3,000 as a practical red line. At 3,000 RPM, you'll be doing about 90 MPH. That's fast enough on truck tires. /ubbthreads/images/graemlins/crazy.gif

 

[kgeorge]

Thanks for information. My new fifth wheel weight is about 14,000 lbs. wet weight. I'm thinking that the tow boss option may be a little more than I need. The 4.10 limited slip may be a better way for me to go. Thanks again for the info.

 

[SmokeyWren]

[ QUOTE ]
My new fifth wheel weight is about 14,000 lbs. wet weight.

[/ QUOTE ]

Hmmmmmmmmm. 14k trailer plus about 9k for a wet and loaded Dooley pickup is 23,000 pounds GCW. Close to the GCWR of the Dooley PSD.

If it were my money, I'd go with 3.73 rear end up to about 17,000 to 18,000 GVW. 4.10 up to around 20 to 21k. 4.30 for anything over about 21k.

If that "wet weight" is the GVWR of the trailer, then you might be happy with 4.10. But if that's a WAG and the trailer has a GVWR of more than 14,000, then I'd definitely go with the 4.30.

 

[AllDiesels]

if most of the trucks time is spent towing i would go with the tow-bos, i have it and i love it, now my truck is also my daily driver to and from school unless i drive the mustang so that kinda stinks, but it does great pulling my heavy tractors and camper. And it gets better milage towing than my 03 with the 3.73's got but a lot less emty. For example my 03(CC swb srw 7.3) got about 19emty on the freeway and about 12 pulling my camper. my new truck gets about 15 emty but 14 towing the same load.
robert
out

 

[lincster]

If I can get 15mpg empty with my Tow Boss I will be dancing a jig. I got 13.5mpg with my 04 SRW F350.... consistently.
Plus I hope to get 10mpg towing my 15,000lb toyhauler. That will be great!!!! /ubbthreads/images/graemlins/biggrin.gif

 

[powerboatr]

I test drove a tow boss with the 4.30 gears, at 72 she was "estimating" 16. MPG and this was on 20 or so miles.

 

[lincster]

I am very interested where my EGTs are going to run at freeway speeds. Want to put my gauges in this weekend.
Good thing about these 4.30 gears, it makes the tranny shift up quick and having the TC locked helps in cooling.

 

[powerboatr]

I am betting the egts run cooler than those of 3.73 gears.
the one I test drove seemed very responsive getting up to speed, almost like it was loafing. the little boost guage in the IP didnt appear very responsive, I geuss it gets electrical input vice straight pressure, I got it to go to 30 lbs but at highway speeds it seemed to hold right at 10 or less.
going to look at the 06 again this week, almost bought it two weeks ago, now i am convinced it will tow the new fiver.

 

[lincster]

I agree, the stock boost gauge is not very responsive. My 6.0L in my 04 made my needle move pretty quick.

 

[SeanBH]

kgeorge:

I have a 05 F350KR DRW, Tow Boss, with stock 18" [email protected] 70mph, I'm just almost exactly 2500rpm. It is sooooo sweet how it pulls my 40' WW. And Smokey is right based on your weights- don't try anything less.

 

[SmokeyWren]

[ QUOTE ]
I have a 05 F350KR DRW, Tow Boss, with stock 18" wheels ...

[/ QUOTE ]

You have a rare truck if you have stock 18" wheels on a Dooley. All the other 2005 Doolies have 17" wheels. /ubbthreads/images/graemlins/warmsmile.gif

 

[SeanBH]

[ QUOTE ]
[ QUOTE ]
I have a 05 F350KR DRW, Tow Boss, with stock 18" wheels ...

[/ QUOTE ]

You have a rare truck if you have stock 18" wheels on a Dooley. All the other 2005 Doolies have 17" wheels. /ubbthreads/images/graemlins/warmsmile.gif

[/ QUOTE ]

Smokey:

Again, you're right! I guess I assumed the 18's that came with the King Ranch were "stock"....me bad! /ubbthreads/images/graemlins/grin.gif

 

[lincster]

Just an update.
I am on my 2nd tank of fuel, I am getting 13.9mpg with 700 miles on the motor.
This is 75% highway at about 72mph.
I am very happy with this considering I am doing better than my 04 SRW.