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i have a 91 e150 im thinking of going with a 4.10 gears in it but how would that affect mpg. like how much would i lose. and im thinking of doing the rebuild my self .oh also i have an aod with wide ratio plantaires.
Depends on where you drive, if it's around town, stop and go, it'll improve or stay the same, hwy could possibly decrease your MPG, unless you have problems keeping it in OD, if so, it'll stay in OD, possibly increase MPG.
Unless you have the tools and knowledge, I suggest you to take it in, or you could possibly ruin the gear, carrier and housing from improper alignment, costing you a fortune to have corrected. Look for another van with the ratio you are wanting, cost is cheaper this way, and it's already setup/broke in.
What is your current ratio, if higher than a 3.55, that would be a lower number, you wouldn't want a 4.10, more likely a 3.73 or 3.90 maybe. I have 3.50 gears, wanting to swap in a dually axle from a box van with a 4.10, wanting a dually, needing lower gears.
where would i get a diff with 4.10 gears.a junk yard? and how do i tell what ratio it is or what model van has 4.10 ratio.thanks .oh and how much mpg loss are we talking on the hwy like 3mpg .thanks
MPG loss depends on the size of jump you make with the gears, and if you have had issues with it holding in overdrive on the hwy. There is a metal tag on a bolt of all differential covers in vehicles, it tells the gear size, if it has a limited slip differential or open axles, as well as codes for various other things. Sometimes they are disposed of when serviced, not everyone puts them back.
The change in mpg will depend on what the current gear is and what kind of driving you do. You didn't say what gear was in it now or what motor (although I am betting its a 5.0).
As a note: My 5 liter came with a 3.31 and I use it mostly for interstate towing. I swapped the 3.31 for a 3.55 and the towing milage went up about 15% while the unloaded interstate mileage went down slightly. Around town is about the same.
i know someone who swapped to 4.10 in a 94 f-150 and had trouble with the trans shifting wrong. he found out that the pcm controlled the trans and it would have to be reprogramed. don't know if this applies to yours but you might want to consider it before you go to all that work
A '91 should have a plain AOD automatic. AOD's are not electronically controlled.
My van has an AODE which is electronic. It shifts fine after the gear change but the high end of the speedo reads erratically and the speed limiter hits at about 90 mph instead of 98 mph.
i guess im going to get the gears from summit and try to install them i think i can do it .oh and say i go on a long trip with lots of luggage and weight by using 4.11s could help my mpg loaded
You need to know what gear ratio you have, a carrier for anything higher than 3.73, you can't bolt a 4.10 gear, you'll need another carrier, unless you have a 9" Ford axle. Then you need all new seals, gear oil and bearings. If you have not done this before, Have it done, there are tools required for measuring lash and some require other special tools for dis/reassembly.
The carriers are sized for the gears, 2 sizes, one to 3.73, and another for over, buddy, if you don't know this already you'll be in over your head, have it done by someone who knows how, and has the proper tools. This job is not something that can be done under the van, and definately isn't a swap out.
you have made up your mind. so do the swap and tell us how it goes. shiming it should be no problem (you do have a depth gauge or at least a micrometer huh). not your only vehicle is it. do it and keep us posted