3.73's going in whats gonna be my rpm

[Double-S-Diesel]

sent the 96 down to Greensburg Driveline on wed to have the rear pinion and carrier bearings replaced, I know something wasnt right with it.
Mark called me up and says bearing spun on the pinion.
need new pinion.
so new ring and pinion on the way.
gonna be the test dummy for 3.73s.
now I really got to find a front set.
how do I figure final drive
96 with an 88 s-42 zf5
3.73 gear, 315/70/16 tires,(34.2" tall)
was running 2250 at 70 before.
Nick

 

[tonkadoctor]

Here are some calculators Nick http://www.rocky-road.com/calculator.html The one you want is second from the bottom of the page.

The ZF5 5th gear is .76 and I come up with 1950 RPM at 70 mph with 3.73 gears in your truck. Should put you close to the sweet spot for economy.

 

[Double-S-Diesel]

thanks TD
I was thinkin I should be around 18-1900
will find out for shure when I get the truck back.
I have gps to get true speed, then all I need to do is recal the speedo, with the 315s it is about 6mph off.
gears wont affect it, but tire dia does.
nick

 

[Double-S-Diesel]

Dammit just found out my gears got delivered to greensboro
not to greensburg.
all weekend and no truck now.
on top of that it needs 2 ujoints.

 

[tonkadoctor]

Oh that bites. Did they land in Greensboro, PA or Greensboro, NC.

If NC I'll pick them up for ya and point them in the right direction if you need me to.

 

[Russ]

Dammit just found out my gears got delivered to greensboro
not to greensburg.
all weekend and no truck now.
on top of that it needs 2 ujoints.

Ouch that sux. BTW Wanna race this weekend ?

 

[tonkadoctor]

Ouch that sux. BTW Wanna race this weekend ?

That's gonna leave a mark.....Race line up will prolly look like this


Nothin' like a good when yer down is there.

 

[Double-S-Diesel]

got it back monday, took it for a long ride.
at 70 mph (gps) it was a needle over 2000
at 50 it was right around 1400
seems to run better with more useful rpm in any gear. doesnt redline as fast.
very happy with the swap.
thanks to Mark and Pat at
http://www.truckpulls.com/Greensburg_Machine.html

 

[rubberfish]

You'll like the 3:73's
I swapped out 4:56 and am happy.

 

[sle2115]

Having had 3.55's then converting to 4.10's, I think 3.73's would be the perfect gear. Good pull, without overrevving. If I ever switch, that is what will go in mine.

 

[Double-S-Diesel]

Having had 3.55's then converting to 4.10's, I think 3.73's would be the perfect gear. Good pull, without overrevving. If I ever switch, that is what will go in mine.

I was gonna go 3.55 until I put the bigger tires on.

 

[Double-S-Diesel]

towed with it last weekend, had to downshift a little more, but I did go from 285s and 4.10s to 35's and 3.73s.
over all I love em.
dont know about the mileage yet, hard to measure when your mixing fuel from oil cubies.