Been tossing around the idea of swaping 4.56 gears into my 1990 22RE pickup. The truck came stock with 4.10's and 235 tires. The truck has newer 31" tires on it now and the speedo is off around 5mph. I would like to keep the 31" tires as they suit the truck and have a lot of mlejs left on them, but I would like to have everything work as it should. Like having a accurate speedometer. I know that the 31" tire was an option on some truck.

What parts do I need to make my truck like these 31" option trucks?

 

Were you thinking of trying to find some used gears? Or seting up new ones in your diffs?

 

I think the 31" option trucks with manual transmissions sometimes came with 4.30's
But 4.56 is a good ratio for that combo. And comfortably you could even run 32's

 

Just find some used 3rd members. Just sold a set to a guy on here and he said that it was the best money he ever spent. I think he has about the same setup that you are after.

 

4.56 and 31s rock! I say do it!

 

Sounds like a good plan if the price is right. If you can only find 1 diff with 4.56 for a fair price consider getting 1 locker and 1 open.
The amount of MPH error on your spedo will increase as you speed up. Your actual error in % is constant. On my rig with 31" tire and 4.10 gears I get about 10% error. So when you calculate your miles per gallon or speed with this set up add 10%.

M / G x 1.10 = corrected MPG

Where:
M = miles driven according to your odometer
G = Gallons used

But I digress

 

Uh...wut? Not sure what your saying here, but make sure the gears in the front and back of your truck match.

 

That is the gist of it. I am saying that you can mix and match different lockers and open diffs. depending on the deals that you can find and your budget. As far as matching front and rear I assume that you mean gear ratios.

 

you'll be happy no matter which gear set you get, as long as it's lower than 4.10. definitely get F/R matching ratios if you plan to use 4wd again. if you get 4.56, i would think about upping a tire size a smidge to a 32" and gain a few MPGs back on the hwy. should drive pretty much the same as your combo now.

personally, i knew that my truck would be less DD and more for fun with at least 33s (or larger, lol), I decided to skip 4.56 and look for 4.88s. since my 31s had a ton of meat left, i ran that combo for nearly 2yrs when i finally found a smokin' deal on CL for some 33s. eventually, i'm sure i'll upgrade to 5.29s
i got my best gas mileage with stock 4.10 and 31s - once, I somehow got 27mpg (adjusted) with injector cleaner in the tank on a road trip - but I mostly averaged somewhere around 22mpg (adjusted) hwy with that setup - i'm guessing this is what you're getting now. when i swapped in the 4.88s/31s i was somewhere around 18mpg adjusted. now, with a "stock" ratio (4.88s/33s) i get around 20 hwy which i guess is normal

regardless, MPG has nothing to do with the increased torque you'll be getting at the wheels

 

I have 4.56s and 33s and I love it...I'm going back to 35s when my 33s wear out and I don't plan on regearing. I also have the R150 so 1st, 2nd, and 5th are just a little taller than your W56, but nothing significant.

4.56s and 31s aren't too bad at highway speeds...the W56 has a .85:1 5th gear so you'd be at 2730rpms at 65mph. I say do it.

 

Thanks for the I info guys! What trucks or 4Runners should I be looking at for finding a set of 4.56's? Can I tell what gears a Toyota has without pulling the diff?

My other main concern is having the truck display the correct MPH and odometer reading. How can I correct this?