Gears for Towing Please

[bass-o-matic]

Hi.

I have a 2002 3rd Gen.
15 inch wheels.
99' in the back
5100 bilsteiens
air bags in coils

Tows my 3200 lb trailer nicely but when going up hills I'm kicking down and doing 5k + RPM. That can't be good. OD off by the way.

OctaneJunkie and other say gears. I'm starting to agree.

What gears should I get?

Any threads on replacing them?

Anyone know a shop in Austin?

I hear you drop the axle, remove the bolts, Pull out the shafts. put in the new gear cluster. reverse... oversimplified.

Thanks for any advice

 

[Acorn22]

A little tough to say... New gears will definitely help with towing the trailer, but driving without it will cause you to be driving at highway speeds at a much higher RPM than normal, especially in a flater area such as Austin.

Is it a 2wd or 4wd? Do you ever plan on getting bigger tires or adding additional weight (bumpers/sliders/skids...etc.)?

If you are thinking about adding extra beef to your 4runner then you are going to want to take that into consideration so you don't feel bogged down a second time and have to regear again. However, if you want to keep it stock then that definitely makes the decision a lot easier.

Assuming you have stock 4.10 gears, I would probably make the jump to 4.56 gears if you plan on staying stock; that way it will be a noticeable difference with towing without having to sacrifice too much top end speed without the trailer.

As for the install of the new 3rd member, it's not too hard and can be done in a couple hours with pretty basic tools. There's some writeups out there for sure, just do some searching around. If your 4runner is a 4wd though, it is going to be a lot harder because you'll have to swap the front diff too with the same gears that you would buy for the rear. And pulling the front diff out is a PITA!!

Finding used diffs is pretty easy and cheaper than regearing your own as well.

 

[pauldub]

Assuming that you have 4WD, you'll need to change the gears in the front too. It wont be cheap. Are you trying to improve performance or just lower the RPM? If you lower the RPM, you'll reduce performance.

 

[JayRolla]

If your on small tires then only thing that will help is a supercharger.

These things are gutless stock. They are in my opinion to be used for towing in emergency or one off situations. I would never use it as a main tow rig.

 

[bass-o-matic]

I finally got the door code deciphered. I have 3.46 gears.

My bro suggests 4.11 but he's not a Toyota guy specifically but he will put them in. He's an experience mechanic... 30 years or so.

I have 27 inch 15 inch tires.

Attached is my door sticker.

He asked me to ask you guys do they need to be shimmed?

 

[spartacus]

I finally got the door code deciphered. I have 3.46 gears.

courtesy ou jomentum on ttora forum
1st digit= ring gear

A= 7.5"
B=8.0"

2nd & 3rd digit= gear ratio

01=3.583
02=3.727
03=4.100
04=4556 or 4.30
05=4.700
06=4.875 or 3.909

4th digit= # of pinions

A=2
B=4
C= 2 Pinion OEM limited slip

 

[bass-o-matic]

I finally got the door code deciphered. I have 3.46 gears.

courtesy ou jomentum on ttora forum
1st digit= ring gear

A= 7.5"
B=8.0"

2nd & 3rd digit= gear ratio

01=3.583
02=3.727
03=4.100
04=4556 or 4.30
05=4.700
06=4.875 or 3.909

4th digit= # of pinions

A=2
B=4
C= 2 Pinion OEM limited slip

Oh, by the way Spartacus Thanks for the tip on Airbags. They are awesome!

 

[bass-o-matic]

Oh, so I have 3.58. Close enough


".38 .39.. whatever it takes."

 

[jgue467]

Tows my 3200 lb trailer nicely but when going up hills I'm kicking down and doing 5k + RPM. That can't be good. ...

Well starting at the end, 5k rpms aren't 'bad'.

Interesting how an 01's and 02's gearing can be so different.

I also tow about 3500# in the texas hill country, which imo are very mild hills, not anything like mountain passes.

My rig will tow at 70mph doing 2150rpms, when overiding OD it'll get up to 3400 at 70mph. So not sure how yours gets to 5k around here unless you just like to. I've done 5k, but that was when I had to shift down to 2nd while climbing a 9+ degree road grade in colo while trying to maintain 55+. These trucks could really use a turbo or supercharger there.

:cowboy:

 

[spartacus]

Oh, by the way Spartacus Thanks for the tip on Airbags. They are awesome!

yeah air bags definately help in leveling out the back of the rig.

 

[gamefreakgc]

Oh, so I have 3.58. Close enough


".38 .39.. whatever it takes."

Regearing a size that did not come stock (4.56, 4.88) is not an easy job. It takes a lot of skill including setting backlash, etc. that takes finesse and skill and not for a first-timer.

That being said, you can easily find stock 4.10 gears on a junkyard 4Runner. You could swap out the entire 3rd member and if you do not have 4WD, you only have to do that. If you do have 4WD, you'll need to see if you can swap the front differential as well, not sure about that though.

I use this gear ratio calculator often, as I am hoping to jump to 4.88's on stock tires in the next few years for gobs of torque. For you, moving from 3.58 to 4.10 will increase the RPM as follows:

65 MPH: 2065 -> 2355
80 MPH: 2531 -> 2898

That's with overdrive on. http://www.grimmjeeper.com/gears.html

 

[phattyduck]

My truck has the "A01A" axle/gears stock (with 15" wheels) and it actually had the 3.73 gears from the factory. That's probably what you have, otherwise your highway RPMs would be way low (below 2k rpm at 70mph in 4th/OD).

Since you are 2WD, it will be a quick, easy and cheap rear end swap to 4.10's that tons of 4WD guys are getting rid of.

That will be 10% more torque to the wheels at any given road speed and shouldn't drop your highway MPG much. Speedo, transmission, etc. will be unaffected.

-Charlie

 

[bass-o-matic]

Thanks sir.

I don't see any write-ups. Do you know of any or if they new set of gears requires shimming?

Best

 

[bass-o-matic]

Regearing a size that did not come stock (4.56, 4.88) is not an easy job. It takes a lot of skill including setting backlash, etc. that takes finesse and skill and not for a first-timer.

Gear Ratio Calculator

Oh, I'm not going to do it buy my well grizzled brother.

 

[thegipper]

Thanks sir.

I don't see any write-ups. Do you know of any or if they new set of gears requires shimming?

Best

If you replace the entire 3rd member with a different one that has the gears you want, there is no shimming or special work required. You just remove the axle shafts (only need to slide them back far enough to clear the differential), disconnect the rear drive shaft and unbolt the 3rd member.

I bought a wrecked 99 4runner with the same gear ratio as my 97. The reason why I wanted the 3rd member in it was because it had a eaton trutrac limited slip diff installed in it.

It took me a couple hours to swap it in. Hardest part is lifting the 3rd member back in place without disturbing the FIPG/RTV on the mating surfaces. You'll want a helper because the 3rd member is pretty heavy and I'm a big dude.

Good luck

 

[octanejunkie]

Agree 4.11 is a good and easy ratio and swap. What's your tire size/OD?

If you replace the entire 3rd member with a different one that has the gears you want, there is no shimming or special work required. You just remove the axle shafts (only need to slide them back far enough to clear the differential), disconnect the rear drive shaft and unbolt the 3rd member.

THIS ^^^
Be careful of dragging or resting the axle shafts on the internal axle seals or you will have a leak soon enough.

It took me a couple hours to swap it in. Hardest part is lifting the 3rd member back in place without disturbing the FIPG/RTV on the mating surfaces. You'll want a helper because the 3rd member is pretty heavy and I'm a big dude

I swapped my third member in and out alone, twice, but I'm also less of a man today than I was then; I also used a paper gasket instead of FIPG. The hardest part for me were the drive shaft to pinion flange bolts, those suckers are tight and you have to be crafty to loosen and tighten them back to torque (crows foot on a torque wrench)