Questions/Options for JLR 38" Build

[c20040215]

I've seen folks in JKs bend the tubes on D60s doing that lol. They were on 40s and the rocks weren't small, but a built Jeep with some oomph behind her will fuck up all kinds of axles lol

That's why I said smart decision making is important. You can break anything if you make bad decisions.

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[roaniecowpony]

If I was going to do it again, I'd go right to a rear D60, whether full float or just semi float. The front I'd do a Pro Rock D44.

But maybe you're a very careful crawler and you may do fine with the D44s. But if you're a lead foot, D60s may be better for you.

I have 4.5" backspace wheels with 37s. That doesn't leave much room for big diameter shocks when you put the shock outboard relocation brackets on. I am running the bottom feeder Rocksport shocks, which I'm happy with for crawling. But they aren't great for situations where you're really working the shocks.

As for the lift, 2.5" doesn't sound like enough for 38s unless you go fenderless. Even then, you may run into compression travel limitations you don't like.

 

[AcesandEights]

Would appreciate some feedback and input before I drop a chunk of change...

I don't wheel hard, and it's a daily driver, but I live in the Rocky Mountains and am daily on mountain passes, forest roads, etc. and want reliability more than rock crawling potential...

Where are the weak points? Other comments on drivetrain, brakes, etc. are welcome.

-emphasis added

The weakest point is 38" tires on a vehicle that isn't wheeled hard. Other comments, it's poor decision making unless you wheel hard; hard on drivetrain, brakes, etc. You'd be better off with 33" tires.

 

[Testingthewaters]

While everything's apart and a big project is underway, thoughts on rear axle truss? The various weak points on the front have been identified and are known, is the rear less subject to stress and/or at less risk? Rear shaft recommendations would be welcomed, too. Super grateful for the input!

 

[grimmjeeper]

While everything's apart and a big project is underway, thoughts on rear axle truss? The various weak points on the front have been identified and are known, is the rear less subject to stress and/or at less risk? Rear shaft recommendations would be welcomed, too. Super grateful for the input!

The rear axle carries a lot more of the vehicle weightwhen climbing. So more stress on parts.

I trussed my 44 and put in chrome molly shafts.

 

[kah.mun.rah]

While everything's apart and a big project is underway, thoughts on rear axle truss? The various weak points on the front have been identified and are known, is the rear less subject to stress and/or at less risk? Rear shaft recommendations would be welcomed, too. Super grateful for the input!

With everything already apart and the welder already out for the front, trussing the rear will probably only cost you an extra $200 for parts and labor. Whether you need it or not, having one is at least worth $200 in style points.

 

[JMP]

Something that folks also rarely talk about is that, unless you go to a much larger tire, you lose clearance with a D60 vs a D44. The housing and tubes being larger on a D60 do add strength, but they do lower under-axle clearance. If you go from 37s on a D44 to 38s on a D60, you've lost a solid 1-1.5" of clearance, if not more. For that tire size and weight, I'd rather have the clearance of the 44 and hit my axles on stuff less.

This isn’t true anymore. Lots of high clearance castings out there. They are only about 1/2” less clearance than a D44.

My D44 needs a skid on the rear. Putting in a modern D60 and ditching the skid would GAIN me 1/4” of pumpkin clearance (skid added 3/4”).

Center of tubes to bottom of skid/pumpkin:

- Old school D60: 6”
- New school D60: 5.75”
- D44: 5.25”
- D44 with skid: 6”

I’m looking at going with a light D60 and 38 Nittos. I’ll gain a total of 1” over my D44 with skid and KM3 37s. It’ll put me at a bit over 12” of pumpkin clearance.

 

[Remorseless]

This isn’t true anymore. Lots of high clearance castings out there. They are only about 1/2” less clearance than a D44.

My D44 needs a skid on the rear. Putting in a modern D60 and ditching the skid would GAIN me 1/4” of pumpkin clearance (skid added 3/4”).

Center of tubes to bottom of skid/pumpkin:

- Old school D60: 6”
- New school D60: 5.75”
- D44: 5.25”
- D44 with skid: 6”

I’m looking at going with a light D60 and 38 Nittos. I’ll gain a total of 1” over my D44 with skid and KM3 37s. It’ll put me at a bit over 12” of pumpkin clearance.

Why does your D44 need a skid? You could simply run an upgraded diff cover just like the D60's going to have and keep all the ground clearance. No skid + 38s on the D44 would certainly net you more clearance than the D60.

 

[chevymitchell]

Why does your D44 need a skid? You could simply run an upgraded diff cover just like the D60's going to have and keep all the ground clearance. No skid + 38s on the D44 would certainly net you more clearance than the D60.

The need comes from the structural ribs designed into the housing casting.

There's about a 2" gap that once a rock gets in there, you won't be able to back up or go forward without a higher risk of damage.

That's the only reason I see a "need" for one. I'm sure there's a picture floating around here somewhere of what I'm talking about. I don't have any Jeeps here at the shop today otherwise I'd just take one.

 

[grimmjeeper]

Why does your D44 need a skid? You could simply run an upgraded diff cover just like the D60's going to have and keep all the ground clearance. No skid + 38s on the D44 would certainly net you more clearance than the D60.

Earlier JL D44s came with a drain plug in the bottom of the housing. Dragging that over a rock can damage it and cause leaks. A smooth bottom diff may show scratches but it won't leak.

 

[Remorseless]

Earlier JL D44s came with a drain plug in the bottom of the housing. Dragging that over a rock can damage it and cause leaks. A smooth bottom diff may show scratches but it won't leak.

It's on the side in the rear, it was only on the bottom in the front. They specified a skid in the rear.

 

[grimmjeeper]

It's on the side in the rear, it was only on the bottom in the front. They specified a skid in the rear.

Yeah, I forgot about the rear. I was thinking the front.

 

[Remorseless]

The need comes from the structural ribs designed into the housing casting.

There's about a 2" gap that once a rock gets in there, you won't be able to back up or go forward without a higher risk of damage.

That's the only reason I see a "need" for one. I'm sure there's a picture floating around here somewhere of what I'm talking about. I don't have any Jeeps here at the shop today otherwise I'd just take one.

The vertical ribs that extend out laterally from the housing and create that little valley? Seen plenty of folks drag that without getting a rock stuck in there.

 

[chevymitchell]

The vertical ribs that extend out laterally from the housing and create that little valley? Seen plenty of folks drag that without getting a rock stuck in there.

Agreed. It's just risk mitigation. Dragging slowly is different than smashing into it. For me, something like Metal Cloak's golden diaper was a no brainer and cheap insurance.

 

[chevymitchell]

Here's the pic I was thinking of in case others aren't sure what we're speaking to.

It's a MC pic.

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