Gears and Lockers

If you do decide to go with a gear change before you make the leap, go to the gear calculator on the website, it’s listed above in the useful links page.  Lets you play around with different combo’s.  It will show you just what the gears will do to rpm on the road and on the dirt.  And pay attention to final drive ratios.  This is more important on the rocks than the rpm of the motor.  See what you have stock right now then compare with new gears, the final drive ratio is where the difference shows.  First gear shows how well the rig will work in the rocks and 4th (or 5th if you have it) tells you how it will behave on the highway.  The way my diesel is set up I have a final drive ratio of about 55 to 1.  The low first in the tranny and the 2.29 low range in the t-case account for most of this by the way.  And just for comparison a stock FJ 60 on 31’s only has about a 30 to 1 final drive ration in 1st and low range.  Quite the difference.

And I have some words of wisdom about the gear calculator and auto trannys.  An auto functions in such a different way than a manual transmission that some of the numbers do not compare with a manual tranny.  You can wheel just as hard and get over the same rocks with higher final drive ratio’s in an auto due to how it works internally.  The gear calculator is more useful for the rpm and mph info with an auto than the drive ratio’s.

What gear ratio you use is a personal choice but a lot of it depends many factors, tranny and tire size being the most important.  Since most of us have changed out the tires for a larger size, you need to remember just what they left the factory with.  Your door tag will tell you, most of them had only 29in tires.  Put this into the gear calculator and you will be shocked at just how much you have already handicapped your rig.

In a stock 60, 4.11’s work well with 33’s but are not that much different than 3.70’s, only about a 10% change.  You might even be able to find a pair of used 3rd members from a 62 that would bolt right in.  Eric still has the stock 4.11’s  in his 62 but he runs an H41 that has the low first gear (same as my H55 1st gear).

4.88’s would be a bit much and say goodbye to your top end unless you still have the factory auto in a 62, then it is perfect with 33’s.   This is why I have 4.88’s in the diesel, swapped the axles out of my 62 and just kept the 4.88’s.  This combo of the auto and the 4.88’s was perfect in the 62. If you are running 33’s on a 62 swapping the gears to 4.88’s will give you all your factory power back and let the tranny run like it was designed to.  Once you drive one with this combo you will see just how bad the rig drives with 4.11’s and 33’s.   And Eric can confirm this, as at one time both of our 62’s had auto’s and 33’s.  Only difference was the stock 4.11’s in his and the 4.88’s in mine.  The difference is night and day.  Don’t let anyone tell you differently.

In my diesel,  top speed is about 65 with a screaming motor!  And that is with a 5 speed.  I drove it to Oregon while I still had the 4 speed, after a 100 miles wife said I could buy a 5 speed.  I drive this thing to work everyday (22 miles on a rural highway) and it is no problem but remember, I have 5th gear which is an overdrive and driving over about 50 on the way to work is not much of an option.

4.56’s seem to be a popular change but it will impact the highway mph and mileage due to a higher cruising rpm.  If I did a gear change again I would probably go with 4.56’s just for the slightly better manners on the highway.

I went with Yukon gears and they seem to be holding up just fine.  Just had the rear 3rd out recently to change some O-rings in my airlocker and the wear seems to be OK, nothing ridiculous and no metal on the drain plug so thats a good thing.

Another possibility for re-gearing comes from a conversation with Ken Eshelby at Cruise the Woods in 2010  His idea is to throw a Marlin Toybox in to a stock rig with the four speed and gears you already have.  Great idea as you keep all your road manners and still get a really low first.  The Toybox is a 4 to 1 reduction gear that fits between the tranny and tcase.  Takes some mods (driveshafts and cutting the output shaft of the tranny) but should run about the same as paying for a gear change but only if you do the install yourself.

Changing out the tranny for a 5 speed is another option.  Even though the H42 4 speed has better road manners, I do love the low first gear and overdrive  of my H55 both of which are pretty much  mandatory for how I drive my rig and for the gears even with 33’s.

If you are going to someday put in lockers, I would do it at the same time as the gears.  Kill two birds with one stone.  But once again the cost goes up.

What would I do today?  I would take a hard look at the toybox option.  Gets you the low range you want and keeps all the good manners on the road.  Might be just what you are looking for but I haven’t used one (even though I want one).  Main drawback is cost.

My second choice would be a 5 speed or possibly an H41 with the low 1st.  I would look really hard at the H41 option if I was on a budget as this would get you the most bang for your buck.  You get the really low first, which gives you a final drive ration of almost 40 to 1.  While you lose some of the road manners, this tranny doesn’t affect your highway mileage like a gear change would.   And these trannys are reasonable in price compared to all other options.

3rd choice would be the gears.  And I would only change them in conjunction with other changes, meaning low gears only if you will be getting an overdrive to compensate on the highway, 5 speed or an auto or some other type of overdrive.  But if you could find a set of thirds with 4.11’s (all ready in them) cheap I would definately do that regardless of any other change.

If new gears become your only option I would more than likely go with 4.56’s in a stock 60 running 33’s and 4.88’s in a 62 with the same tires.  For the expense 4.11’s may not do it for a stock 60 and 4.88’s would be too much without an overdrive.  62’s start out with the 4.11’s but run much better with 4.88’s.

And don’t forget that tires are the poor mans gear change, shorter tires equate to lower gearing and taller tires are the same as higher gears.  It’s not called the rubber overdrive for nothing.

Now that I have made it clear as mud…    Unfortunately none of these options come cheap.

-Lockers-

The difference between lockers and open diff’s makes the cost of lockers worth every penny.  Not that all options are really expensive but none of this comes cheap.

The least expensive option is Aussie Lockers or Lockrite’s.  These are just a kit that converts your stock open diff to a locker.  In the rear you don’t even have to remove the axles, just pull the cover, swap the parts in the kit and your are good to go.  While generally not recommended for the front axle if you engage the front axle on the road for snow and the like, Eric has had a Lockrite in his front axle for years and it has never been a problem.  He has just learned to drive a bit different in the snow.

The other end of the spectrum is selectable lockers.  Not only do they lock up the differentials, you can also turn them off with the flick of a switch.  Then they work just like open differentials.  You can get them in electric or air operated versions.  I went with the ARB’s as they are readily available and have a proven track record.  I love the fact you can unlock the front end when you want to turn and they do not effect the on road use of 4WD.  I used to chuckle when the guys with lockers went to turn and couldn’t!  Found out why once I installed my ARB’s….

Detriot Lockers are another option.  Lots of guys run these in the rear axles of their rigs.  A little noisy on the road but less expensive than air lockers and have a good reputation to boot.