RV8guy

I have a 1989 1 ton dually with 4.10 gears out back. Does anybody make a ring and pinion in the neighborhood of 3.50? Google search has not been kind to me lately.

Second question. Would there be any issues with swapping out the 1 ton springs with half ton versions? I don't really need the load carrying capability any more but would like to have a bit better ride.

RV8guy

Anybody know where I could find a 3.56 ring and pinion?

the_supernerd

I believe some turbo trucks had 3.42 gears in an 8 inch differential, but that will be tough to find. As long as the springs bolt up, which I would think they would, you could just get a 7.5 inch axle and spring set from a regular 1/2 ton Toyota pickup. Lots of 7.5 inch 2wd trucks had a 3.42 differential, and I think some had a 3.58 or something close. If I remember correctly, according to my sales brochure from 1987, 3.58 gears are on Sport, non-turbo extended cab 2wd trucks (other trucks of other years probably have that ratio that I am unaware of). 7.5 inch third members will also swap with a 2wd Tacoma, which gives you access to more ratios and newer gears. Somewhere in my mind I remember certain Tacomas (maybe automatic 4 cylinders?) come with 3.58s. Search for Toyota axle codes, then print out the list before you go to the junkyard. That will help while you search, but I would verify that the original gears are still in the truck by counting the number of times the pinion turns while you turn an axle shaft. Get the speedometer gear out of the transmission while you are there so the speedometer matches.

If you want a better ride, then you have to swap the springs, but keep in mind that if you have a large flatbed or an RV, the regular 1/2 ton springs will not support it. I am still researching if removing springs from a pack is going to cause problems, and I actually just posted a thread about it, but I do know there can be a lot of springs in the 1 ton packs if removing some ends up being a good solution for a better ride.

RV8guy

Thanks for the info. I know that Toyota has codes for taller gears but I have yet to find a set. The after market has mostly nothing. I have found some 3.73 gears and will go that route if it's my only option.

I wish that I could find toyota trucks in junk yards. I would like to pick over some looking for a few things and maybe some spares. There is nothing in my area.

MichaelKLerner

Hi, I have a 1988 Extended Bed pickup. I am not sure what gears are in it, but I think its 3.73. I really want to get more low end power. but I am having trouble finding 4.10s. I don't think there are any taller gears available to fit my housing, but I am not sure. Any advice you have would be appreciated.

As for springs, there I'm an expert so I would be glad to advise you.

the_supernerd

As far as I know, 3.73 is as low as you can find with stock gears and the 7.5" housing. There are 8 inch, 5-lug, 2wd housings available that should be able to use a 4x4 third member, which is easy to find in a 4.10 ratio or lower. These housings can be found on one-tons, turbos, and certain 4-speed trucks. On the VIN tag, look for the axle code G. Code F is 7.5". Most of the 4 speed trucks I have worked on with the 8 inch differential have the code G662, which is 3.07 gears. Those will be much easier to find in the junkyards than a turbo or one-ton truck. Your axle shafts from the 7.5 inch rear will be different, so you will need those, also.

MichaelKLerner

This is very helpful. Thank you. It will take me a while to digest this, but I think I am getting it.

By the way, please tell me, What is meant by passenger side drop diff versus driver side drop diff? What is drop referring to?

MichaelKLerner

Can a Toyota V6 rear axle be used in a 4 cyl truck?

the_supernerd

Passenger/driver side drop refers to the location of the differential on the axle. Some axles do not have the differential carrier, where the driveshaft connects, centered in the axle. This is usually in reference to front axles, but some rear carriers are not centered, either. This is not an issue with your truck, as the rear axle has a centered carrier. From what I understand, a 4 pinion third member (V6/turbo) can be used in the 8 inch rear axle housing.

MichaelKLerner

I kind of figured that's what drop meant, but as mine has no drop, I cannot understand why there is so much discussion of it on some sites that are supposedly about my truck.

Apparently, if you have a 7.5 inch rear there are no options, and you need to change to an 8-inch rear before the fun really starts?

Now what I am wondering is, do all 8-inch rears have 6 lugs, or are there 5 lug units as well?

And, are all 6 lug rears 1 ton, or only some of them?

MichaelKLerner

To answer my own question, yes, 8" rears with 5 inch lugs are available, but rare. Easier solution: use a 6-lug to 5-lug adapter. Does anyone have any recommendations for this?

the_supernerd

5 lug 8 inch rear axles are not as rare as some people think. 4 speed trucks with 3.07 gears have them, which are much more common than 1 ton trucks. I have personally owned a couple of them, and have seen a few in the junkyards. I would think that you could find one at a Pick-n-Pull in your area fairly easily. Look for axle code G662 on the VIN plate under the hood (or an G axle code). More than likely you can find a 4.10 third member while you are there (more than likely in a V6 4Runner), then make sure it fits the housing you want to buy to make sure no one has swapped it out for a 7.5 inch axle before it ended up in the junkyard. I am not sure if a speedometer gear from a 4x4 truck will work on a 2wd truck, but you might grab that at the same time if it looks like it will fit so your speedometer will be correct.

MichaelKLerner

Thank you for all the advice I have received.

While learning about Toyota truck axles, I have had to unlearn a lot of what I have been told locally, which was that the only solution for me is a 1-ton rear diff with 4.10 gears. Having read countless articles, pored through Craigslist and Ebay, and Google Images, I have managed to get a broader understanding of how a solution could come together for me through more readily available parts. Just when I thought I was on a new and rewarding path, a local yard came up with ... wait for it.... a 1-ton with 4.10 gears!! Recently wrecked truck, well-maintained, pretty clean.

This ends, at least for now, my quest for the ultimate rear-end build-up for my handyman worktruck, as I have the newly acquired axle sitting in the truck bed, to be installed with the existing 1-ton springs, in the new year.

Thanks again, everyone, Mike