88 22R hauling 1K-1.5K pounds of cargo, 90 percent city driving, relatively flat landscape, with occasional steep grades,

8-inch rear end with 4.10 gears, 27-inch overall diameter rear tires.

Currently, 3 - 3.2K RPM will get me to 65 in 4th gear. I never get to use 5th gear because I run out of torque after 70, given my weight and wind resistance. And I don't want to go faster than 65 anyway because stuff gets airborne and flies out of the back of truck.

Right now, I have decent torque and acceleration on flat ground, but I struggle when launching on hills.

Every time I drive I keep thinking there's more torque on hills, and more acceleration at the traffic light, if only I gear down with taller rear end gears.

Am I wasting the opportunity to use 5th gear at 65 MPH and get more power out of the lower gears? s

Can I live a fuller life by going from docile to brutal, by going from 4.10 to 4.56 (skipping past 4.3)?

Or would I be either overtaxing my engine by constantly forcing it to over-rev, or ruining my drivability and fuel economy by having to constantly shift gears?

Because this is an expensive mod and expensive to reverse, I want to get your advice.

Thanks for reading,

Mike

 

I recently switched from 4.10 to 4.56. I was running 30x9.5 Cooper STT Pro after swapping to 4.56 I’m
now running 33x10.5 BFG all terrains. I will say that the 30” tires with 4.56 made me feel like my rpm’s were too high and I like it better with the 33’s. I hadn’t planned on running the 33’s but found a good deal and they look nice 😊

In your situation I feel like 4.56 gears with 27” tires would be too low for my liking but that’s just my opinion. Have you considered finding a factory 8” third member with 4.56 gears to just swap in the rear to try out? 4.56 were a pretty common ratio with certain combinations of engines, trans and wheel sizes so you might be able to find one for a reasonable price to swap in and see if you like it. If you don’t you could just swap your 4.10 third member back in.

Here is a good resource on gearing and ratios with a helpful chart. Round Forge Gear Ratios

Here is another resource for information on Toyota 8” axle ratios and combinations. 4Crawler Toyota Differentials.

And more info on Toyota Diffs 4x4 Wire Differentials

I hope that helps give you some more information to make up your mind.
Happy Trails,
Winky

 

Thanks for your considered response.

Sounds like you might be have a 6-cyl engine. As far as revs are concerned, number of cylinders matters a great deal and 4k RPM on a 6 cyl is a hell of a lot more piston speed and noise than 4k on a 4-cyl engine.

Would you please clarify what kind of engine you have.

 

When I bought my 88 pickup from my friend (original owner) he had 4.56's with 31" tires and it was perfect. Might be a bit low for the 27" tall tires. If it is, you could always go up in tire diameter easier than swapping gears again. Oh, it had a 22RE and W56B 5 speed. I hope this helps.

 

W56B 5-speed: are there any other 5-speeds I should know about?

FYI, 8-inch rear ends for singe wheel axles are rare near me, and dualies are a nonstarter. The one I've got is probably the only one I'm ever going to own. I'm one short of a pair just to get the 4.10!

Going up in tire only works if you have 4wd. You can't fit taller tires under a stock RWD pickup than the 27s I already have. I tried, anything taller will rub unless I jack up the rear to a ridiculous rake.

So I am stuck knowing what to do. I figured a 4.56 would give me a 5th gear I could use on the highway between 60-70. Right now, I can't use 5th at all. Seems a waste to have a gear there that I can't use.

Thanks for your help.

 

Hello,

I’ve got a 22re (4 cylinder) with a w56 manual trans and 4.56 gears, now I’m running 33 x 10.5” BFG all terrains on my 4WD. 5th gear isn’t really an option unless I’m over 60 on the interstate which is rare. 31” tires would put my ratio back to stock but I like the look and extra clearance of the 33’s.

 

Mike you're right about not being able to use 5th. My son's truck was like that until we swapped gears but his was a 4x4 and he had bigger tires.

I think you should swap gears. I just don't know if you'll be happy with 4.56's and a 27" tire. If you've done the math and it's in an acceptable RPM range, go for it. You won't be happy if it's screaming either. 4.3's "might" be a better choice IF you spend a lot of time on the freeway. If it's surface streets, the 4.56's will definitely make it snappy. JMHO. Good luck with which ever you choose.

 

Their just 3rd members. Change them out in an hour. Buy all the gear ratios you can find and swap them out every other week to see which ones best. Then sell off the rest. Haha.

 

MarlinCrawler has a great tranmission page

https://www.marlincrawler.com/transmission

 

Thanks, I think I will eventually go for 4.56s because I really went to press the boundaries

 

I'm glad you made the decision. Please let us know how you like it once it's done.