Another rear end question....

[BuzzGun79]

if it was me the 3:73 would be the better option for overall use,gives you a little more gear for towing,without sacrificing a great deal of cruising economy,It should keep the rpm's below the 3k range still imo.Its kind of a Happy medium between the 3:54-4:10.when you get into the 4:10 range, yes it is a good pulling ratio but the tach needle rises as well at cruising speeds.3k-3500 rpm range is my educated approximation

 

[LEB Ben]

Here's the rpm break down at 60 mph with 30" tires:

3.07's- 2063 rpm
3.54's- 2378 rpm
3.73's- 2506 rpm
4.10's- 2755 rpm

Now if you're not towing and cruising the highway at 70:

3.07's- 2406 rpm
3.54's- 2775 rpm
3.73's- 2924 rpm
4.10's- 3212 rpm


You're biggest shock factor is going to be swapping the 3.07's. I think 4.10's would be pointless for your application. 3.73's put you on the upper level of the sweet spot and a little too far over for highway cruising IMO. If it were me, I'd find a good D60 rear with 3.55's and call it a day...swap the axle in and you have an afternoon and $250 in to the whole process.

 

[Workin' Rig]

So 3.55's (or 3.54's) is my best bet...even though i want more pulling the truck still spends 90% of its time bobtail....

How exactly do you make sure a junk yard rear is in good shape? Make sure the pinion dont slop and minimal leaks?

 

[LEB Ben]

Minimal bearing play...minimal oil seepage...avoid obvious damage. If possible, pop the diff cover off, check for rust and busted teeth...it's like 12 or 14 9/16" bolts. If it were me...I'd probably go ahead clean it up anyway with new seals, paint, etc.

 

[m78]

I've got 350 gears in my E350 and have no problem towing anything up to 8k lbs. (Flat lander)

 

[Workin' Rig]

I was planning on replacing the seals unless the rear looks good and solid. Maybe ill take me a 9/16 socket and pop the cover off and look inside...thanks for the help guys i appreciate it.

It pulls my camper pretty good with 3.07's but it gets a little aggravating on hills, and i feel like it woudl be eaiser on stuff in general.

 

[BuzzGun79]

Ben does have a valid point in his explanation workin..and the 3:54 will be a considerable jump in ratio from what you have now.It will also be easier on fuel mileage than the 3:73.The 3:54 is a good all around gear i have them also and no complaints here.It comes down to your personal choice and how you use the vehicle to get the most of what you want out of it.

 

[LEB Ben]

^^^Yeah...I have 3.55's in my Bronco with 35's...leaves a little to be desired off the line, but they do the job.

 

[BuzzGun79]

Ben quoted "^^Yeah...I have 3.55's in my Bronco with 35's...leaves a little to be desired off the line, but they do the job."

This may sound Crazy to you Ben..Mine is a pig to move in reverse,especially when it is cold...Now drive i cant complain really soon as i hit the throttle it is off and i am really quite impressed at how the truck accelerates off the line .Now it could be engine/trans combo's between the two and how their setup,but hey i am happy with it so far.

 

[m78]

I always thought a 2 speed rear end would be handy. To bad they don't offer it for this size trucks.

 

[Workin' Rig]

I wish my truck had a 4sp then id pry be ok with the 3.07s.

 

[m78]

Here's a 300 for sale.
http://norfolk.craigslist.org/pts/3288208762.html

 

[Workin' Rig]

^^^^^^^Best engine ever built^^^^^^^^


Youll never ever change my mind of that...i was always a believer but one day at a mud bog when i seen a guy overheat (to the point it was steamin), and then hydrolock a 85 300 and then dry it out and drive it home....defintaly made me a believer....