School Bus Conversion Resources

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-   -   Looking for information on locking differentials (http://www.skoolie.net/forums/f33/looking-for-information-on-locking-differentials-29465.html)

dzl_ 11-22-2019 11:56 PM

Looking for information on locking differentials
 
When I first began looking into Skoolies my plan was to find a cutaway ford E-450 and at some point in the future convert it to 4wd. Because Ford vans are so ubiquitous and Sportsmobile and a handful of other companies outfitted E-Series vans for offroad overland use there is a pretty great little cottage industry and community centered building out this chassis for offroad use.


Fast forward a few months and I've now begun to favor a conventional style short bus for a number of reasons. But i've found its much much much harder to find information, knowledge, and aftermarket support for conventional buses.


If I went with a conventional Skoolie (dognose) I would give up on 4x4 unless I found a great deal, but I would still want to outfit the bus for moderate off pavement use.


I would like to put a rear locking differential in it. Preferably a selectable (air or electronic) locker, but would also consider a limited-slip.


Searching the forums I have found many vague mentions of lockers in the abstract but no concrete details or first hand knowledge. Have any members added aftermarket lockers to their buses? Can anyone point me towards companies that make lockers for medium/heavy duty axles?

banman 11-23-2019 09:28 AM

Quote:

Originally Posted by dzl_ (Post 360277)
When I first began looking into Skoolies my plan was to find a cutaway ford E-450 and at some point in the future convert it to 4wd. Because Ford vans are so ubiquitous and Sportsmobile and a handful of other companies outfitted E-Series vans for offroad overland use there is a pretty great little cottage industry and community centered building out this chassis for offroad use.


Fast forward a few months and I've now begun to favor a conventional style short bus for a number of reasons. But i've found its much much much harder to find information, knowledge, and aftermarket support for conventional buses.


If I went with a conventional Skoolie (dognose) I would give up on 4x4 unless I found a great deal, but I would still want to outfit the bus for moderate off pavement use.


I would like to put a rear locking differential in it. Preferably a selectable (air or electronic) locker, but would also consider a limited-slip.


Searching the forums I have found many vague mentions of lockers in the abstract but no concrete details or first hand knowledge. Have any members added aftermarket lockers to their buses? Can anyone point me towards companies that make lockers for medium/heavy duty axles?

Me-thinks you're barking up the wrong tree --
Find out what kind of axle you have -- then research the parts available for that axle. Then try and see what other rigs used that axle. Many medium duty dump trucks, gravel trucks, construction site etc. would've wanted a locker as they frequented muddy sites. A used detroit locker will probably be available and affordable... Selectable would be cool but expensive or even unubtanium...
But you're not alone -- I will probably go this route -- I don't wanna get stuck in a muddy field or two inches of snow... Better treaded tires than my road slicks will obviously play a part in the traction equation...

PNW_Steve 11-23-2019 09:50 AM

I have been told that the International CE's share many components with the International medium duty trucks.

One gent claimed that you could buy a used MD 4wd truck and swap all of the truck 4wd components to the bus.

Can anyone speak to this?

I have my eye on a 4wd CE that a local school district has in service. They were going to retire it last June but have been unable to find a replacement. If they don't cut it loose in 2020 I will be looking at a 4wd conversion.

dzl_ 11-23-2019 05:06 PM

Quote:

Originally Posted by banman (Post 360301)
Me-thinks you're barking up the wrong tree --
Find out what kind of axle you have -- then research the parts available for that axle. Then try and see what other rigs used that axle.

I think you are right. It would be easier to find info if I had a particular axle to look into. But I haven't bought a bus yet, so I can't easily slide under and see what axle its got. My search for the right bus has been somewhat focused on early to mid 90's international 3800 short buses. I have been asking around and searching for information on the axle but I get the impression there were many different axles used on these buses.

Quote:

A used detroit locker will probably be available and affordable... Selectable would be cool but expensive or even unubtanium...
You are probably right that something like a detroit would be easiest to find and cheaper.

That said, in the offroad world, the price difference isn't too extreme between selectable, auto locking, and limited slip. Taking the Dana 80 ( upto 11,500 GAWR) as an example a parts site has an ARB selectable air locker listed for $1250, a Detroit locker listed for $950 and a Detroit Truetrac (limited slip) listed for $700. Obviously with the ARB there would be the extra cost of installing an onboard air system if your bus didn't already have them or adapting it if it did. But that price premium for selectable isn't too outrageous.

Not sure how similar those price differences would be with medium duty commercial axles. Or if its even possible to find selectable or limited slip for medium duty trucks (my guess is that the latter would be possible to find not sure about selectable though).

I know that there are some medium duty vehicles like the F-550 (~19,000gvwr) and the Mitsubishi Fuso 4x4 (~14000 gvwr) that are somewhat popular among the overlanding crowd and there is a bit of an aftermarket for 4x4 parts, not sure what axles they use.

One option might be swapping out the stock axle for an axle with better offroad aftermarket support, but I'm not sure how technically challenging that would be.

dzl_ 11-23-2019 05:28 PM

Quote:

Originally Posted by PNW_Steve (Post 360307)
I have been told that the International CE's share many components with the International medium duty trucks.

One gent claimed that you could buy a used MD 4wd truck and swap all of the truck 4wd components to the bus.


I have heard something to the same affect. And it stands to reason that International would use the same chassis and drivetrain components for both lines rather than reinventing the wheel when hauling people instead of things.


Wikipedia seems to vaguely support the notion that the Buses and MD trucks share the same chassis but then also seems to contradict itself at times:


Quote:

Originally Posted by Wikipedia
The bus chassis variant of the International S series [truck chassis] is a cowled bus chassis (conventional style) that was produced by International Harvester (later Navistar International) from 1979 to 2004...

Designed as a replacement for the International Loadstar bus chassis, the S-series bus chassis was produced in two distinct generations. Matching the development of the International S series [truck chassis], during 1989, the model line underwent a major update, becoming the International 3800...

Released during 1979 production, International Harvester introduced the S-series bus chassis alongside its conventional-cab counterpart. Replacing the bus chassis variant of the International Harvester Loadstar...

In a shift from being an adaptation of a truck chassis, the [first generation] Schoolmaster was designed as a distinct model line intended solely for bus use. Along with completely straight frame rails, the chassis was designed with a flat-back firewall, allowing for body mounting with minimal design adaptations...
The Schoolmaster was produced as a variant of the International S1700 and S1800 (Class 6 trucks)...

In 1989, Navistar introduced the second generation of the S-series medium-duty trucks, renaming the Class 6 range the 4000 series. Ending the use of the long-running "Schoolmaster" product name, the bus chassis received a separate model designation; the S-1753 was replaced by the 3700; and the S-1853 was replaced by the 3800.

Its not completely clear from the wikipedia article how identical the school bus and MD truck lines are, but it seems clear that at the least they are adaptions of the same chassis/drivetrain. I know the old loadstars were pretty much the same whether you got the bus or the truck version, but the article makes it sound like they may have begun differentiating the two lines with the S-series/3X00 series, but without knowing specifics hard to say how that would affect swapping over 4x4 parts.


I was looking at an old Loadstar a couple months ago that I'm kicking myself for not jumping on. It was an old 1960's search and rescue vehicle 20 foot bus body, 4x4, manual transmission, with a 2 speed rear end. At the time I hesitated because it was packing an old gas engine that apparently pulled like a diesel but only got 3-6mpg.

banman 11-23-2019 05:42 PM

You will find a lot of amazing build info here:
https://www.pirate4x4.com/welcome1.php

*Be advised -- Pirate prides itself in being a rough bunch...
Random "what if" questions will be met with hate...


Easy button...
https://www.pirate4x4.com/forum/102-...tion-vehicles/

banman 11-23-2019 05:57 PM

2 Attachment(s)
Quote:

Originally Posted by dzl_ (Post 360389)
I have heard something to the same affect. And it stands to reason that International would use the same chassis and drivetrain components for both lines rather than reinventing the wheel when hauling people instead of things.


Wikipedia seems to vaguely support the notion that the Buses and MD trucks share the same chassis but then also seems to contradict itself at times:




Its not completely clear from the wikipedia article how identical the school bus and MD truck lines are, but it seems clear that at the least they are adaptions of the same chassis/drivetrain. I know the old loadstars were pretty much the same whether you got the bus or the truck version, but the article makes it sound like they may have begun differentiating the two lines with the S-series/3X00 series, but without knowing specifics hard to say how that would affect swapping over 4x4 parts.


I was looking at an old Loadstar a couple months ago that I'm kicking myself for not jumping on. It was an old 1960's search and rescue vehicle 20 foot bus body, 4x4, manual transmission, with a 2 speed rear end. At the time I hesitated because it was packing an old gas engine that apparently pulled like a diesel but only got 3-6mpg.

Ha, ha! The SV (IHC speak for Small V-8 gas engine) I have an 304 SV (almost the smallest of the bunch in my Scout -- I'm happy to be getting 12mpg with it. Okay, maybe not happy, but it is what it is...
And it's ported with a mild cam and lots of love but it's still a POS boat anchor... It's lipstick on a pig :whistling:
But this is the same engine used in many a 1600/1800 Loadstars, school bus' or combines...

banman 11-23-2019 06:35 PM

https://lmgtfy.com/?q=site%3Apirate4x4.com+school+bus

You're welcome :thumb:
(I'm a @!ck, but I'm a helpful dick...)

dzl_ 11-23-2019 07:16 PM

Quote:

Originally Posted by banman (Post 360413)
https://lmgtfy.com/?q=site%3Apirate4x4.com+school+bus

You're welcome :thumb:
(I'm a @!ck, but I'm a helpful dick...)




Thanks. The problem I've been running into (and continue to run into after sifting through the first 8 pages of google results) is that "school bus" is way too general of a term and "conventional school bus" or "international 3800" is way to obscure a term outside of this site to return any results. It appears the Pirate 4x4 folks have converted many a cutaway to 4x4 (lots of parts and knowledge out there for this as its just a Ford Van with a bus body) and use lots of full sized buses for 'toy haulers' or turn them into flatbeds (and ironically most threads I read refer people back to skoolie.net for school bus specific info), but I can't find any specific or first hand info on conventional bus 4x4 conversions or axle or locker information. I was hoping someone here or elsewhere may have some first hand knowledge.


On another note, my search might turn up more useful info if I could figure out which medium duty trucks used the same axle as an international 3800, as I'm sure there is more interest in offroad capability with trucks than skoolies.


Edit: The search did turn up some pretty cool and some pretty weird looking conversions


Edit 2: I haven't browsed through that expedition section yet, but thanks for the link, that is probably my best bet for finding info on medium duty vehicles. I am frequent expeditionportal.com which has a ton of great info on everything overland but not much on skoolies. The most popular medium duty chassis' seem to be Unimog, Fuso, F450/550, and some of the European makes.


Edit 3: God i love the look of those classic old scouts, and yup, i'm pretty sure that's the engine the loadstar had in it, it may have been one of the higher displacements siblings.

dzl_ 11-23-2019 09:30 PM

Without any idea what axles were common on international or any other buses I'm kind of just stabbing in the dark. But so far I have found that:


  • The Dana 80 (upto 11,500 gawr) will take a ARB selectable air locker, a Detroit TrueTrac limited slip, or a Detroit locker
  • The Dana/Spicer S110 (14000 gawr) will take a Detroit Truetrac limited slip
  • The Dana S135 will take a Detroit locker
  • The Rockwell 2.5ton will take an ARB selectable air locker or a Detroit locker
I will update this list if I come across more relevant info


Anyone know if any of these axles are common on bus chassis'?

banman 11-23-2019 10:20 PM

Quote:

Originally Posted by dzl_ (Post 360447)
Without any idea what axles were common on international or any other buses I'm kind of just stabbing in the dark. But so far I have found that:


  • The Dana 80 (upto 11,500 gawr) will take a ARB selectable air locker, a Detroit TrueTrac limited slip, or a Detroit locker
  • The Dana/Spicer S110 (14000 gawr) will take a Detroit Truetrac limited slip
  • The Dana S135 will take a Detroit locker
  • The Rockwell 2.5ton will take an ARB selectable air locker or a Detroit locker
I will update this list if I come across more relevant info


Anyone know if any of these axles are common on bus chassis'?

I'm familiar with the Rockwell 2.5 ton as it's found on many military trucks usually with the detroit locker...

If you're set on an IHC bus/truck than this is the place to ask about what axles lived where. And the binderplanet is a much friendlier place than Pirate... It's helped me with my Scout quite a bit over the years...
Triple Diamond Trucks | BinderPlanet

dzl_ 11-23-2019 11:17 PM

Quote:

Originally Posted by banman (Post 360453)
I'm familiar with the Rockwell 2.5 ton as it's found on many military trucks usually with the detroit locker...


It seems like it is a somewhat popular axle with the hardcore offroad crowd as well, so there looks to be much more aftermarket support and knowledge out there for this axle. For that reason alone it is an attractive sounding axle. And with all the military surplus stuff out there axles and replacement parts would probably be easy to come by.


Quote:

If you're set on an IHC bus/truck than this is the place to ask about what axles lived where. And the binderplanet is a much friendlier place than Pirate...
Triple Diamond Trucks | BinderPlanet

Thanks, I'll check it out. I'm not set on an International but it is top of my list at the moment. I remember coming across that site when I was researching that 4x4 Loadstar I mentioned earlier. Seemed like people there have an impressive depth of knowledge when it comes to IH.


Thanks for the links and the guidance!

Booyah45828 12-02-2019 04:01 PM

If you're dealing with full sized buses, most axle manufacturers will have some sort of locker/limited slip option available. You're aftermarket options from eaton/detroit and the like won't be available on the larger axles.

If you need a locking differential, I'd go with the previous suggestion of finding something used from a dump truck or semi. A lot of those will have either something automatic or an air operated locker that you engage with the wheels stopped. If you're good/lucky, you might find one with more desirable rear gear ratios to boot.

Brad_SwiftFur 12-02-2019 05:37 PM

I did a quick search for "N175 locking differential" and rather quickly found a reference to "Eaton NoSPIN" locking differentials - apparently similar in operation to a Detroit Locker. I believe ARB Air Locker might offer one for my axle as well (or maybe another company makes air lockers for it?)

Booyah45828 12-02-2019 09:48 PM

Interesting, my 2013 catalog from dana shows the n175 as an obsolete axle. Try ordering a no spin and let us know what you come up with.

EastCoastCB 12-03-2019 02:50 AM

Here ya go!
https://www.eaton.com/content/dam/ea...tion-guide.pdf

Brad_SwiftFur 12-03-2019 03:13 AM

Quote:

Originally Posted by Booyah45828 (Post 361858)
Interesting, my 2013 catalog from dana shows the n175 as an obsolete axle. Try ordering a no spin and let us know what you come up with.


I don't know if the N175 was discontinued production in 2013 or not but many thousands of these axles are still on the road so I'd imagine parts will be available for quite some time to come.

Ronnie 12-03-2019 07:11 AM

Quote:

Originally Posted by EastCoastCB (Post 361889)


That is a great reference, think i will save it. Thanks

Elliot Naess 12-07-2019 04:47 PM

Quote:

Originally Posted by Booyah45828 (Post 361813)
If you're dealing with full sized buses, most axle manufacturers will have some sort of locker/limited slip option available. You're aftermarket options from eaton/detroit and the like won't be available on the larger axles.

If you need a locking differential, I'd go with the previous suggestion of finding something used from a dump truck or semi. A lot of those will have either something automatic or an air operated locker that you engage with the wheels stopped. If you're good/lucky, you might find one with more desirable rear gear ratios to boot.

Yes, most of the 18-wheelers I drove over 27 years had air-controlled locking diffs.
Check with Acme (used) Truck Parts in Stockton, dzl.
https://www.acmetpe.com/default.htm

Brian S 12-07-2019 05:34 PM

Try ujointoffroad.com. They sell Ford Van conversion kits and have a pretty good discussion of not only the kits but also axles and transfer cases.


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