HJ60 Gearing (4.11->4.88) (1 Viewer)

[zander]

So I want to change the gearing on my 1987 HJ60 and I am getting confused and contradictory answers to my questions from most of the resellers. I would like to hear from someone with experience.

I want to change from the 4.11 stock gears to 4.88 so that I will have better torque (this should return me to close to original ratio given my 33" tires).

Can any of you with experience in this change over give me an idea of what to order and who from?

(My HJ60 has the A440 auto trans and the 2H diesel motor, I have installed an Auburn LSD in the rear I would like to keep)

thanks in advance for your time,

 

[HZJ60 Guy]

Well, are you sure that the gears in your truck are 4.11's?

You can get the gears from Man-a-Fre, or Spectre, or Randys Ring and Pinion. There are many places. You'll want the gears, and install kits too.

Have you done the math to determin where you want to be RPM wise on the highway?

That auto as I remember has a pretty good overdrive so you can go low without to much worry.



TB

 

[Radd Cruisers]

So I want to change the gearing on my 1987 HJ60 and I am getting confused and contradictory answers to my questions from most of the resellers. I would like to hear from someone with experience.

I want to change from the 4.11 stock gears to 4.88 so that I will have better torque (this should return me to close to original ratio given my 33" tires).

Can any of you with experience in this change over give me an idea of what to order and who from?

(My HJ60 has the A440 auto trans and the 2H diesel motor, I have installed an Auburn LSD in the rear I would like to keep)

thanks in advance for your time,

Pretty sure the HJ is 3.7s, pick up a set of thirds with 4.11s.

 

[HZJ60 Guy]

I thought that the gears were 3.73.

You might consider 4.56's instead of the 4.88's.

TB

 

[crushers]

ALL CDM auto HJ60 came with 4.11 gears not 3.7 (37 teeth on the ring and 10 teeth on the pinion) the BJs came with the 3.7 stock.
the 4.88 will be a bit steep, i would suggest 4.56 max.
but then that is just my opinion.
cheers
Wayne

 

[lowenbrau]

The auto does have a bit more OD than the H55f. Nominal 33s will likley have you in the 2900 rpm range at highway speed.

Just order fine spline 4.88s from Randy's. If anybody asks, tell them its an FJ62. The diffs are the same.

 

[zander]

Good to get that input... Yes the axle codes on my truck show that it is indeed a 4.11 (K08) The gear calcs I used seem to indicate that the 4.88 gets me back to stock. But I am open to 4.56 as well if that is more accurate.

I used the first calculator on this page:
http://www.off-road.com/tools/gearcalc.html
and plugged in 28" for stock tires, a diff ratio of 4.11 and left the tranny at 1 and got 50.3mph at 2500 rpm. Then I put in 33" tires and 4.88 and got 50.7mph so that is why I considered this the comparable swap.

Thanks for the note about the FJ62 being the same. So they have the same "HD" axles as my rig? I am double checking because when I put in the Auburn LSD it took 3 bearing changes to find the correct one as they kept being confused by the HJ60 "HD" axle.

ALL CDM auto HJ60 came with 4.11 gears not 3.7 (37 teeth on the ring and 10 teeth on the pinion) the BJs came with the 3.7 stock.
the 4.88 will be a bit steep, i would suggest 4.56 max.
but then that is just my opinion.
cheers
Wayne

 

[Radd Cruisers]

ALL CDM auto HJ60 came with 4.11 gears not 3.7 (37 teeth on the ring and 10 teeth on the pinion) the BJs came with the 3.7 stock.
the 4.88 will be a bit steep, i would suggest 4.56 max.
but then that is just my opinion.
cheers
Wayne

I did not know that, thought it was the same as my BJ60 wagon, even the HJ with five speed was 4.11?

Rob

 

[crushers]

according to the micro the standard has 3.7...
cheers

 

[HZJ60 Guy]

Good to get that input... Yes the axle codes on my truck show that it is indeed a 4.11 (K08) The gear calcs I used seem to indicate that the 4.88 gets me back to stock. But I am open to 4.56 as well if that is more accurate.

I used the first calculator on this page:
http://www.off-road.com/tools/gearcalc.html
and plugged in 28" for stock tires, a diff ratio of 4.11 and lef the tranny at 1 and got 50.3mph at 2500 rpm. Then I put in 33" tires and 4.88 and got 50.7mph so that is why I considered this the comparable swap.

Thanks for the note about the FJ62 being the same. So they have the same "HD" axles as my rig? I am double checking because when I put in the Auburn LSD it took 3 bearing changes to find the correct one as they kept being confused by the HJ60 "HD" axle.

ANytime you're talking about gear changes you're talking dollars. You MUST be sure of yourself before you make the move. Remember this, no tire measures true to size.

When I did the gear calculations for my truck I figured in 36" tire because that's what my 37x12.5x17 Goodyear MTR's actually measure.


TB

 

[beanz2]

I did this very same thing with an HJ75, but it started with 31" tires and went to 35" tires. 4.88's did indeed restore the power. No problems hitting indicated 110 km/h on the speedometer with an H55f.

I get my gears from Chimney Canyon 4x4.

Dave

 

[tlcruiserman]

Myth vs reaality

Just thought I would chime in with some truth about gears and changing them:


Myth - gears are complicated and it is hard to get them just right and if you screw it up you will destroy the gears.

Reality - gear are not that hard to put in just a little elbow grease and you are set, as far as setting the bearing pre-load and backlash a $6 measurement gauge at harbor frieght (if you do not have access to one) is all that is needed, well plus a work bench.

I am amazed at how much they charge to put in gears and how many people pay it.

Just my 2cents here.

Michael

 

[Sixty's Guy]

I too have been considering this. My HJ60 came standard with 205R16 tyres (29.3") and 4.11 gears. I have now gone with 33x10.5x15 tyres (32.5") and using a gear/rpm calculator, the new gears to restore factory ratios is 4.56

I have been contemplating going 4.88 anyway (H55f) in case I go with 35" tyres later. Or I could go a turbo. Not sure at the moment!

 

[zander]

Sounds like you are in much the same situation as I am, and you are running the same tires. interesting youa re getting a different number for the ratio though. I wonder where I am calculating wrong... I need to get the real measurement of the tire size but currently I am doing 58mph at 1700 RPM on flat ground.

I am definately heading towards turbo as well since I spend so much time at altitude. But I dont think that changes much.

I too have been considering this. My HJ60 came standard with 205R16 tyres (29.3") and 4.11 gears. I have now gone with 33x10.5x15 tyres (32.5") and using a gear/rpm calculator, the new gears to restore factory ratios is 4.56

I have been contemplating going 4.88 anyway (H55f) in case I go with 35" tyres later. Or I could go a turbo. Not sure at the moment!

 

[Sixty's Guy]

Sounds like you are in much the same situation as I am, and you are running the same tires. interesting youa re getting a different number for the ratio though. I wonder where I am calculating wrong... I need to get the real measurement of the tire size but currently I am doing 58mph at 1700 RPM on flat ground.

I am definately heading towards turbo as well since I spend so much time at altitude. But I dont think that changes much.

I get a differnt gear ratio to you as maybe the original tye sizes are different between the two countries. You mentioned 28" - what size tyre was this?

 

[zander]

I get a differnt gear ratio to you as maybe the original tye sizes are different between the two countries. You mentioned 28" - what size tyre was this?

Good point. I got that off a site. I have an old set of stockers I should measure...

 

[Sixty's Guy]

Mine was a one owner vehicle when I bought it and I still have the original owners manual, so mine definetely came out with 205R16 tyres.

 

[The Dude]

On my HJ61 with the auto I went with 5.29s and 38s. My brother in his HJ60 and 5 spd went 4.56s and 33s...He regrets not going with 4.88s.

With the auto I would go steeper!!! 4.88s for sure. With it's steep OD you will not regret the decision. It seems that with an auto, the ratio is always one step higher then with a standard...

I have never heard of anyone complain about going to a taller gear, lots regret under gearing...

 

[zander]

Just order fine spline 4.88s from Randy's. If anybody asks, tell them its an FJ62. The diffs are the same.

Nobody has part numbers for my 87 HJ60 it seems, but they do have the part numbers for an FJ62. They are all asking if I need the bolt kit ($50/end) as they cant tell if an 87 needs it or not, anyone know the answer to this question?

Any recommendations on the install kits for an HJ?

Sorry I am a bit gun-shy here as the last time I tore my diffs down it took three tries to get the bearings right for the LSD install (and this is my daily driver). I REALLY want everything on hand I may need.

 

[Mike S]

My 2F (pretty close in power to your H engine) has just enough power for most roads, and the H55F lets me run in 5th at over 70 MPH with 31" tires at 2500 RPM. This is with the 3.73 RE. If I went to 33" tires, I'd go to 4.11 to get back close to stock. In my opinion, the 4:88 set is too low for decent highway performance.

The other option is to shift down to 1:1 when you need more power.

My OPINION.

M