4 Cylinder Rear End Gear Change

lonestar816 · #1 04-16-2015, 05:49 PM

Alright, so I just installed some beautiful new rims and tires onto my 2.5L 5 speed 2wd 2001 Ford Ranger. I went from 235/75R15 (when I bought the truck) to 265/75R16. Now because of this I sadly lost some power and I haven't been able to figure my current gas mileage yet.

So my question is if I swapped from my current 3.73 gears in the rear to 4.10s what kind of differences would I notice? My truck does have a couple miles on her and I don't want to blow out the engine from running it too high RPMs on the highway. However I do like a little power to have fun with. So I'm debating what I should do. I travel highway quite a bit for school so fuel economy is nice. However if I am not sacrificing too much I would love just an extra kick of power.

Just let me know if any of you have past experiences with this, I'd love to hear!

hat_man · #2 04-17-2015, 06:42 AM

I've looked into a rear gear swap but haven't done it yet. The 3:73 are a nice "middle ground" gear for in town and highway. I'm afraid with the 4:10's you would be running really high RPMs on the highway. Especially at 65-70 mph. The new tire and wheel combo is probably heavier and making it harder to get going with the extra rotational mass. I'm not sure about the 98+ models because I have a 97, but if you have the dual coil packs look up the dual coil pack mod. It doesn't help a lot with MPG (a little though) but it does help out on the low end. Once you get up to highway speed the rotational mass issue starts to go away. You could always go the other way and look at the 3:55's but with the larger wheel and tire combo getting started from a stop will be SLOW. Good highway mileage though. If your going to do a swap you'll have to research whether it will be cheaper to swap out the internals of just get a new rear end from the pick-n-pull and have it installed.

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Look for a guy here named nathan01xl. I'm pretty sure that's his name. He has an '01 and is getting GREAT mileage. Maybe he can be of more help than I can.

Like I said I don't have a 98+ model so I don't know about the computer and changing tire size. If there is an option to "reflash" the 'puter for the new tire size make sure you have done that or your speedo and odometer will be slightly off. If you are doing the simple math to figure MPG and the odometer is off the math will be off.

I went from the stock 225/70/14's on mine to a 215/75/15. My speedo reads 3mph slower than I am going. 55 mph on the speedo and I'm actually going 58 mph. 285 miles on the odometer is actually 300 miles. There are a lot of good tire size calculators out there, just Google them.

lonestar816 · #3 04-17-2015, 01:21 PM

Yea I have already figured how far off my speedo and odometer are off. My truck reads 9 of every 10 miles I drive. The plan is to fix that, however I need to figure out if I want to do the swap before I pay the dealership to reprogram the computer with the new perimeters. With the new tires my RPMS are about 500 or so lower at highway speeds right now. So I've determined if the 4.10 gears only raise it about that much I will more than likely do the swap.

Tyler46 · #4 04-19-2015, 01:44 PM

I have 4.10 gears and stock 225/70/15 tires. My RPMs in 5th at 65-70 mph is like just under 2k. Here in Socal, you have to cruise at around 80-85 with the flow of traffic where my RPMs are no higher than 3k.

So if you have 31's, your RPMs on the highway would be lower than mine ideally.

lonestar816 · #5 04-19-2015, 06:34 PM

It would be nice if my truck ran at that low of RPM in 5th on the highway. With my 3.73s I was running probably around 2750 and now with the new tires I'm sitting around 2250 at 65-70mph. Did your truck come stick with 4.10 or did you do a mod? And if so do you remember what you were getting before?

casey.mikl · #6 04-19-2015, 07:28 PM

Your 3.73 will keep you at lower rpm on the highway compared to 4.10. At 75 with my 2.3 auto and 4.10 on 31s I am right around 3000-3100 rpm.

Tyler46 · #7 04-19-2015, 07:40 PM

Yes, mine came stock with 4.10's. And Casey yours is actually at that RPM? I figured it would be lower. You have lower gears and bigger tires than me.

casey.mikl · #8 04-19-2015, 08:26 PM

Quote:

Originally Posted by Heyman46

Yes, mine came stock with 4.10's. And Casey yours is actually at that RPM? I figured it would be lower. You have lower gears and bigger tires than me.

I also have an automatic. 3 speed with over drive.

GLH · #9 04-19-2015, 09:41 PM

So it's a 4 speed auto.

Tyler46 · #10 04-19-2015, 10:28 PM

I mean I do have a different engine and transmission.

casey.mikl · #11 04-20-2015, 04:11 AM

Quote:

Originally Posted by Heyman46

I mean I do have a different engine and transmission.

Yes that will change it up

lonestar816 · #12 04-21-2015, 06:50 PM

Hmm well I'm not completely swayed one way or another. I think I'm going to price the swap and decide from there. Thanks for your input everyone though.

Tyler46 · #13 04-21-2015, 10:46 PM

You can't go wrong with 4.10's. My mileage isn't too bad either.