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Gear ratios to combine plowing and towing.

Discussion in 'Chevy Trucks' started by cumminswithplow, Dec 20, 2004.

  1. cumminswithplow

    cumminswithplow Senior Member
    Messages: 129

    Just wondered if theres anyone with any suggestions about gearing. What gears are more effective for pushing snow? I have 4.10s front and rear. Works good in the snow. Works good in town pulling my camper. But no power on the highway. Has anyone ever changed gears for the purpose of plowing?
     
  2. PackRat

    PackRat Member
    from Kansas
    Messages: 47

    No power???? 4.11 should be an awesome power gear, unless you are running out of the engine's power curve.
    What is the rest of your combo? Engine, trans, t-case, tires, etc.
     
  3. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    There is no awesome gear to does it all in a pickup. It is a factor of weight, tire size, engine size, altitude and load. a 4.10 is not as formatable with 31's as with 29's and even less so with 33's or more. Plus you have OD which make deeper gear a better option. At the risk of starting a flame war, with a small block you want to be able to turn about 3200 to 3400 at about 65 in drive to get best possible pulling power on a grade with a heavy load and then have OD for the flats or mild grades. This equals out to a 4.56 or 4.88 depending on tires sizes. A "small block" (and the modular V8's) does not make it best power until it is above 3000 towing and running it below that with a load will yeild poor results and poor MPG too. Try to pull a gas engine like a diesel gear ratio and RPM wise will yield poor results.
     
  4. cumminswithplow

    cumminswithplow Senior Member
    Messages: 129

    I have a goodwrench 350 with a mild cam. Suppossed to be good for about 20hp over stock and about 35lb feet of torque. It has small upgrades like k&n filter, dual exhaust, mallory ignition. There is a 2 inch lift with 285's which I understand to be about a 33 inch tire. I have the 5 speed which right now at highway speeds or 65 i turn about 2900. The speed limits here in neb are 75 on the interstate. And with the small engine I have I can forget about ever seeing 75 with any kind of a trailer behind.
     
  5. Midwest BuildIt Inc

    Midwest BuildIt Inc PlowSite.com Addict
    Messages: 1,280

    are you having any engine problems? because my ford has 4.11's , 285'', and 351w. i used to pull around a case 1845c(9000lbs) without a problem. and when on the highway i would usually do around 75 to 80. with the truck empty((5000lbs) i had no problem accelerating from 60 to a 100 without ever coming out of overdrive.
     
  6. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    Not so, years ago I used to pull stock trailer with a GM truck with a carb'ed 350 and a 4 speed manual with 4.10 gears, no OD and 30's and trailer weight between 8000 and 10,000 lbs loaded and I could do 70 to 80 if I wished with little effort. The 285 are killing your high speed performance big time with a load in tow with present gearing. (moving a truck weighing 10,000 lb it easier than moving a 5000 truck pulling a 5000 lb trailer) Some 4.56 would change things a lot. Easy way to find out is to borrow a set of 30's and tow with truck and compare it to 33's. Also, what year truck is it anyway?
     
  7. PackRat

    PackRat Member
    from Kansas
    Messages: 47

    With the 285's, 4.11's, in 4th gear, you should be right about 3000 rpm @ 70mph, or around 3200 @ 75. I'd forget about overdrive, unless you're running empty.

    Just for fun. 285's, 4.11's, .76OD, should be just over 2200 @ 70, and right on 2400 @ 75.

    If the figures are correct, then you are probably working the engine below peak torque range, and the big tires are definitely robbing power.
     
  8. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    4.10's with 33's are like 30's with 3.73's and neither one is a HD towing combo for a small block powered 4x4 truck no matter how you do your math. BTW my 99 K3500 does 2700 @ 60 MPH with stock 30's in drive and I could guess how it would suck with 3.73's with stock tires (equal ruffly to 4.10's and 33's). This 4.10 33 combo will yeild about 2700 at 65 and not good for heavy towing. A 4.56 would yeild about 3000 at 65 in drive and about 2250 in OD at same speed vs 2700 at 65 and about 2030 in OD that has little pulling power. The 350 will surprize you what it can do pulling but it needs to get above 3000 on a hard pull to do its best and 4.10's and 33 will not ever let that happen because even if you increase vehical speed to get those RPM's you have even more load and drag on engine from the increased towing speeds.
     
  9. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    My 7100lb truck went on a towing trip from Niagara to Windsor with a 2500lb tandem axle trailer and 4000lb Jaguar on the back.

    (See first picture in this post: http://www.plowsite.com/showthread.php?t=17148 )


    The truck was running the dead 305 (7 cyls only, one was toast) and the SM465 fourspeed (no o/d) and 4.56 gears with my new 33" rubber (duals on the rear). We used several main highways and kept the speed at or just over 70mph no problem. 70mph was 3250RPM. Easily.

    If a 305 on seven cylinders can do it with 4.56's, a 350 running well should be able to do it with 4.11's I would think...
     
  10. PackRat

    PackRat Member
    from Kansas
    Messages: 47


    While I agree with you on the 350 being a good puller, I can't go with the 3.73's being bad pulling gears. My 91 K2500, has a TBI 350, SM465(4-speed), and 3.73's. It runs 2750 @ 65, on 245-75R16's, and pulled my 1 1/2ton wrecker to Hays and back with no trouble. Maybe not the most graceful in tall hills, but very adequate. 4.11's and 4.56's are great, if you have overdrive, but ALL the manufacturers say NOT to pull heavy loads in overdrive.

    Bottom line in my mind, is too much tire. Why put tall rubber on a work truck? Looks great, but makes ride quality worse, given the extra unsprung weight. All the plow geometry is screwy, too. Unless you have a drop mount, which kills the ground clearance that the big tires are helping.

    Maybe I'm just not reading this thing right.
     
  11. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    The beauty of OD is that you can use some 4.56 or 4.88's if you want and still have a good cruising gear when not towing. If you do not have OD you generaly select one ratio taller than you would with a OD as a compromise between towing and cruising without a load.
     
  12. cumminswithplow

    cumminswithplow Senior Member
    Messages: 129

    Sorry Guys. I gave up hope for the chevy.Had a new motor. Was running great. But I just wanted more power for when I pull the skid loader. Or the camper. The skid loader and trailer weigh around 10k. So today I bought a 2005 dodge with the cummins diesel. Its the four door long box. With 3.73 limited slip rear and 4 wheel drive. Its the first dodge I have ever owned. So we will see how it goes.