PSD drive train questions
 

Is there a simple way to determine final gear ratio in a used PSD?

For example, with stock size tires, XXXX RPMs at YY MPH equals Z.ZZ drive ratio.



Secondarly, is a shorter ratio harder on the drive train than a taller ratio? (I've thought about this, and can think of good arguments for both sides).

Thanx.

ttt

Try this:Drive Train

Final Drive Ratio Computation


The formula is:

Final ratio = (Tire Diameter in Inches x RPM) / (336 x MPH)

2000 PSD 4X4 automatic w/3:73 rear turns approx 2050RPM's at 70MPH with 265/75/16 tires.

I believe the 4:10's turn about 2300-2350 @ 70MPH

Thanks guys.


Does the drive train have more stress (likelyhood of breaking) with the shorter ratio than the taller ratio, pulling a load?

You can take the Vin # and call the dealer they will be able to tell ya from that. What is your concern? I think that your boat is not going to put any stress on that truck what so ever. I pull mine and I keep looking back to see if it is still there. Curts Cig that was substantially heavier then our 302's you could tell was back there but it would hold 70-75 no problem and averaged about 12-13mpg all the way home

Jon: Concern is a strong word; it is more an interest. After using what little gray matter I have on a ponder, I hate to leave it unresolved. Our 10-12,000 lb loads wont challenge either one, heck I pull it now with a stock-drivetrain half-ton burban. (Yes, the breaks and suspension are beefed up on it).

So, do the individial teeth on the gears in a drive train have more stress applied with a short final ratio than a tall ratio, or is it the same.

After all the time we spent on "which freezes faster: hot or cold water?", there should be some good insight on the gear question.

I am going to say that there is less stress on the drive trail with shorter gears. IE causing your RPM's to be higher on the highway. The axle I would think is under more stress however.

Jon