I think the Ford said these changes would add 1MPG. Is that worth it just for that. If you guy would drive more carefully you could gain that.

 

[QUOTE=pilotshot]
I have a job 1 F-350 truck with a 3.73 rear axle and been thinking of changing the rear end to 3.55 I understand that many of the parts are re-usuable in the switch so cost could be about $1000 for axle set and labor.

How much fuel will $2000.(possable cost of job) buy,and if you are only gaining 1 or 2 mpg what are you really talking about. Unless my math is wrong ( probabaly is) looks like it would take about 100000 miles just to break even, at my current highway mileage and cost of fuel.

 

I think that we need to hear from the Job 3 owners before anyone really knows what kind of mpg increase is going to be seen. As far as the break even point goes, that number could change if diesel goes to $4.00 per gallon or more (which may be sooner than we all think). Regardless, someone on this site is going to make the switch, no matter what. Then we'll all know the true cost to do it.

 

So whos going to step up to the plate and slow their engine 95 rpm at 65 mph with the swap from 3.73s to 3.55s?

 

Be my guest! And be sure and let the rest of know how it goes.