4.30 gears 34-36" tall tires and a 1.9 ALH

[obrut]

I have an 80 that I'm building.  I finished doing a W56B and dual case swap and have long term plans for a M-TDI ALH swap.  My truck has the factory 4.30 (4.37?) gears and I currently have 34" TSL, I might swap to 36" at some point and that would probably be the tallest.

Thinking long term, am I better off with the 4.30s for the diesel or does it still make sense to re-gear to 4.88 or 5.29s?

I'm concerned about the lower redline on the diesel and too much gearing especially with smaller tires like 34-36"

[H8PVMNT]

A few years ago I would have said to re-gear for sure.  Recently though my kid slapped a hand-me-down Weber 38 on a later model 22r in his '83.  The thing has so much more power than I am used to I can't even believe it!

He is running 4.10s with 33s and it will pull on my hot 20r with 5.29s.  Actually it runs circles around me.

So armed with this new and disappointing experience, I would say to try it out with the 4.37s.  Be sure to let us know how it goes.

If you aren't happy re-gear later.

[emsvitil]

You really don't need to regear with a dual case.    You can get your lower offroad gearing with the dual case.

[Gnarly4X]

Selecting diff gears is about what RPM do you want for each transmission gear?

With your W56B and your current gearing and 34" tires in 4th gear your engine is turning 2975 RPMs at 70 MPH.  In 5th gear it's turning 2380 at 70 MPH.

What is your peak torque at RPM now?

What would be the peak torque at RPM for a diesel swap?

Highway travel is my consideration.  On my 85 standard cab, I ran 33's with stock 4.10 diffs.

5th gear was not usable for highway speeds.  In 5th gear my RPM was 2338 at 70 MPH – about 1,000 below my peak torque for my 22R.  I had to be in 4th gear at 2922 RPM at 70 MPH.  If I ran at 80 MPH, my RPM was 2672 in 5th gear – just at the beginning of my peak torque range and only usable on the highway with no head wind and on the flat.

As emsvitil said, off-road in 4-wheel drive, the dual cases will handle gearing requirements for practically any wheeling conditions.

Gnarls.

[emsvitil]

What's the torque curve for that engine?

[emsvitil]

Considering the usual lower rpms of diesel engines, 4.30 might be the correct ratio.....................

[obrut]

thanks for the replies.  I noticed my pinion seems to have a little play in it so I was going to pull it apart.  I know that can of worms so I though it would be a good time to change the gears if I need to.  My truck is not a daily driver so it can sit until I fix the pinion.  My other though was if I keep the 4.30 gears then maybe I can find a 4.30 gear elocker to swap into the front and then take the front center section and put it in the back.

BTW is it 4.30 or 4.37 gears in the 1980 trucks?  I think the e lockers are 4.37, is that correct?

[RUGER]

factory toyota pinons are color coated. if look threw the driveline yoke(or unbolt the driveline) the pinion will have a color from the factory. if i remember right pink was 4.10 and red was 4.3 but its been years, im sure there is someone on here that will know fer sure.

edit: http://www.4crawler.com/4x4/4R_TechInfo.shtml  toward the bottom it has the pinon colors

RUGER

[obrut]

4.37 for sure, thanks

[helipilot77]

I'm currently running 4.10's with 35's in my diesel but I did prefer the 4.30's I used to have in it with 31" tires. I am planning to install 5.29's and 40's which should put me close to where I was with the 4.30's when I had 31's. You may end up wanting something closer to a 4.56 if anything different at all.