6x6 intermediate axle

997 Views 24 Replies 10 Participants Last post by Tickford, 2 mo ago

Aussie landy 6x6

Discussion Starter · 2 mo ago

2

Hi guys,
I’ve been trying to buy an intermediate axle for a 6x6 but can’t find one or no company will sell me one without sending my truck for a conversion $35 upto $60k even though I explain my truck is already a 6x6

I own an ex Australian army Land Rover 110 “Perentie” 6x6 that has a 4bd1t I want to change out the LT95 4speed gearbox for a 5/6speed gearbox (auto or manual) but in doing this I lose my 6x6 function
I see a lot of f450 & 550’s, jeeps, dodges chevies using for 9” drive through axles but my GVM is up around 12000lbs & GCM towing my RV Up near 18000 lbs so don’t think the 9” would handle the loads but then I can’t find one for sale anyway
So has anyone here know where I could find an intermediate axle that would fit in my truck capable of these loads or a company that would actually just sell the axle/diff? I was thinking the heavy duty 460/550 diffs would work but can’t find anything on them

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dreamin

· #2 · 2 mo ago

Nice rig. What axle is on it now? Does it only drive the front of the tandom?

irhunter

· #3 · 2 mo ago

Aussie landy 6x6 said:
I want to change out the LT95 4speed gearbox for a 5/6speed gearbox (auto or manual) but in doing this I lose my 6x6 function
I see a lot of f450 & 550’s, jeeps, dodges chevies using for 9” drive through axles

Wow, nice truck.

Why is changing out the transmission impacting your middle axle?

Got a link for those 9" you know about?

I can't think of a 6x6 in the US other than MD-chassis trucks. Like our 5-ton Military trucks which use Rockwells:

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Roy

char1355

· #4 · 2 mo ago

I was wondering the same thing. Normally, the 6x6 function is controlled by the transfer case, not the transmission. From what I read, the front and middle axles are powered off the transfer case in a full time 4x4 mode. The third axle is powered off a PTO on the transfer case. So changing transmission shouldn't affect anything. These are not super heavy duty trucks. Gross vehicle weight is 5500-5600 K. An F450 pickup is rated at 14000 lbs (6350K).

Aussie landy 6x6

Discussion Starter · #5 · 2 mo ago

Hi Dreamin

it has 2 rear drive shafts out of the gearbox with the rear diff selectable so in normal it’s a 6x4 then if you want 6x6 you engage it
The diffs are Land Rover Salisbury 8H

Reactions: 2

irhunter

· #6 · 2 mo ago

Cool. Can you post a pic of the transmission and its two rear outputs?

But, maybe you are using "gear box" differently than we do in the US? Transfer case?

Roy

Aussie landy 6x6

Discussion Starter · #7 · 2 mo ago

Roy,
The gearbox is a Land Rover LT95A
The problem is that the gearbox & transfer case are one piece which makes it difficult to divorce.
The front & middle diffs are constant 4x4 with a vacuum activated diff lock in the transfer case & the rear diff is driven from a selectable pto activated drive to give you 6x6

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irhunter

· #8 · 2 mo ago

Wow. That is cool. Thanks for the pic.

Sort of like a 3-out FWD transaxle mounted front-back.

And, you plan a more-normal transmission and transfer case with a drive through middle axle? And, that will be always-on-aft-2-axles plus a selectable front?

"I see a lot of f450 & 550’s, jeeps, dodges chevies using for 9” drive through axles"

You are saying, those trucks have three axles? I agree with Char, that axles under a F550 would be plenty for your application. I guess it is possible to over-weight axles...but, generally, the risk is over-torque. What motor you got? What is the torque output?

Roy

edpruss

· #9 · 2 mo ago

Sorry your picture of trans/transfer case is so small. Are the same casting/same main shaft? Can’t tell from the small picture. It seems the best idea since transfer case already has proper 6wd outputs to modify input to transfer case to fit whatever trans you use, even divorced if have wheelbase.

Ed in CO

char1355

· #10 · 2 mo ago

6x6 transfer cases are out there, but most are big and heavy units for heavy duty trucks. Here's an article you might find interesting. It's form some strange place called Australia. LOL. https://oka4wd.com/forum/oka-maintenance/1468-6wd-np205 Another option could be to run 2 transfer cases, one in normal position and the second in reversed position. That way you could run 2wd,4wd (1 rear axle + the front), 4wd (both rear axles only), and 6wd (all axles), and you could have high and low range in some modes.

edpruss

· #11 · 2 mo ago

Is your transfer case not useable!

edpruss

· #12 · 2 mo ago

Ed in CO

Aussie landy 6x6

Discussion Starter · #13 · 2 mo ago

2

Edpruss
Hopefully you get an idea or just google LT95
1 - is front diff
2 - middle diff
3 - rear diff
Front & middle are constant 4x4 & rear diff is selectable for 6x6
3 drive shafts out of the gearbox
Transfer case & gearbox are one casting as explained earlier, it is possible to cut the gearbox in half then machine the faces down

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char1355

· #14 · 2 mo ago (Edited)

Yeah Ed, that creature is typically British. Weird. Don't know why they would build the transmission and transfer case in one piece but they did. American military trucks in the Korean War era had a NP200 4x4 transfer case but those things don't like any speed over 45 MPH or they will overheat. Those have a second rear output that could be used for 6x6 but it's not the strongest unit around. There were NP201 and NP202 that were stronger and has PTO output ports. And of course the NP205 was the last child in that list which is ultra strong and could be converted to 6x6 as was shown in that article. Only issue there is there is not switching between 2 and 4 rear. If you use a NP205 that would do 1 rear and front. A second unit of some type mounted in reverse position could do the second rear. You'd even have a host of gear ratios. for the rear section. There would be 2H, 2L, 4H, 4L, and 4 double L. 6x6 would be restricted to 6H and 6L. Would keep the brain active as to what gear the transfer cases are in. You know, there's a point here I may be wrong on because I'm not sure with way the shafts would be turning with the second transfer case reversed. That would be something to mock up before install to see if it functions correctly. Don't want to dive into an empty swimming pool.

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edpruss

· #15 · 2 mo ago

Aussie,
Does Landrover have another transfer case that would work, they make lots of stuff we don’t have here. Cutting in half and machining case might work, but would have to look at innards first.

Ed in CO

Dougal

· #16 · 2 mo ago

There are companies in Aussie making 6x6 Landcruiser conversions using a separate splitter box. There are also Aussies who've swapped 6x6 gearboxes out for Isuzu have cut the transfer off an LT95 to make it a separate transfer:

Australian Land Rover Owners

I don't know if 123Rover50 on there is Keith ( @Tickford ) who posts here but he owned one: Is black smoke due to restrictive exhaust manifold?

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john.r.holbrook

· #17 · 2 mo ago

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ntsqd

· #18 · 2 mo ago

LR calls some of the rear axles that they use "Salisbury", but from the little that I have seen of them they look like what we in the US call a Dana 60.

On the transfercase path, a Dana 18/20 hybrid could get you the two full time rear outputs, but they're a bit small for the truck. I dimly recall that in the NP20X series there was a version made that had both offset outputs. If this is correct then it might be that a similar hybrid of those parts mixed into an NP205 could get you there as well. And a 205 should be close to stout enough for the size of the truck.

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john.r.holbrook

· #19 · 2 mo ago

differentialengineering.com

Differential Engineering

differentialengineering.com

This company makes a 9” pass thru diff.

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IRMtrackTECH

· #20 · 2 mo ago

I always wanted to make a passthrough axle based on either the 9in or the Dana S110. Cutting off the rear cover portion of the housing, welding on a mounting flange like the front, and bolting on a driven carrier or finding a way to tie into the back of the pinion somehow.

It's interesting that the Differential Engineering site says their axles are rated to 1000hp. I would think that would be plenty for the OP's needs.

Reactions: 2

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