Isuzu FC Locking Rear Differential Info

[sae8425]

Can any forum member enlighten me as to which Eaton No-SPIN locker units fit the various Isuzu 2WD F and N series rear axles?

EVERY person I have talked to (in America) has been unable to provide me with ANY fitting information in this regard.

Isuzu axle codes published in the Body Builder Manuals, or shown on cabin labels, are insufficient for cross referencing lockers.

The Eaton No-SPIN Heavy Duty fitting list (2010) itemizes by axle manufacturer, not by vehicle manufacturer (brilliant : NOT).

The local Isuzu dealer and heavy truck repair/service emporiums say they don't have the needed interchange details (******).

It also appears that (ostensibly) identical 'axles' (i.e. OEM codes & weight ratings) utilize axle shafts with different spline counts.

All of this uncertainty is hampering my efforts to convince my partner that we need to buy yet another medium duty truck.

I have been offered a very low mileage 2006 NQR Crew Cab (diesel, 176" wheelbase, 12-foot tipping flatbed, full length 'roof' rack).

However, due to having a property on a 'seasonal' township road, I would need to add a locking rear differential to this NQR.

So; I'm trying to ascertain potential upgrade complications BEFORE purchasing an otherwise VERY desirable truck.

As No-SPIN lockers are OEM fittings in various 4x4 Isuzu FC's, a suitable locker MUST exist: but which No-SPIN would I need?

Isuzu Body Builder Manuals state that the NPR HD, NQR, NRR, and GMC W5500 share the same rear axle.

Eaton told me they have discontinued making No-SPIN units for many (older?) axles (perhaps including all/some Isuzu axles).

I've learned that firms besides Eaton make No-SPIN lockers; but how to cross-reference 'locker X' to 'Isuzu axle Y' eludes me.

Does any forum member know who made the NPR HD, NQR, NRR and GMC W5500 rear axles/components circa 2006?

Is any forum member able to match the Isuzu Axle Codes to the axle manufacturer(s) model/part/series numbers?

Is there any business or person who has the No-SPIN locker fitting information regarding Isuzu FC axles that I'm looking for?

Many thanks to any forum member who takes the time to respond to this post.

 

[Anti-lander]

From the scant research I've done (20 min or so on web) I've found that there isn't a diff locker for npr trucks, there was a factory limited slip option but they are rare and you likely won't just find the unit for sale it will be a complete axle assembly if you can even find one and you will likely have to ship it in from an Asian country's junkyard , again the factory ls was rare to begin with.

If you really want one likely you will have to do an axle swap with some other brand of box truck with lockers or ls available.

I'm not an izuzu owner the only one I know anything about is the dmax so take this all with a grain of salt, but the internet didn't return anything on the subject.

If its not a highway vehicle or taking turns fast I'd just weld the rear diff that will lock it permenatly

 

[charlieaarons]

Locked Drive Systems

Try these people in Australia. They’ve been in business for 20 or even 30 years. Be prepared to answer very specific questions to identify the axle. Like a model number on a tag attached to the 3rd member.
Replace (02) in the phone number with 612.

 

[sae8425]

Anti-lander -

All the Isuzu literature I have states that the 4x4 versions were fitted with No-SPIN lockers, NOT limited slip differentials.

As No-SPIN lockers were Isuzu OEM fitments, I assume that replacement locker units are/were available from ___.

From my perspective the No-SPIN is the MUCH better 4x4 drive solution for heavier, longer wheelbase, 4x4 working vehicles.

Class 5 to 8 No-SPIN lockers have been made by many firms over the years (Dyneer, Eaton, and Tractech are the big names I guess).

Yes, replacing an Isuzu NQR OEM rear axle with a Dana S135/150 axle (for which No-SPIN units are easily available) would work.

Then again, for all I know the NQR OEM rear axle is actually a Dana S135/150 (but it is definitely NOT a Dana S130).

Your absolutely right about the dearth of information on the internet about this subject!

But I absolutely believe the answers to all my questions are buried in some old skool file cabinets/blueprint drawers somewhere.



charlieaarons -

Thanks for telling me about Locked Drive Systems in Australia.

LDS lists 12 Eaton No-SPIN lockers for various Isuzu trucks from 2 tonne to 10 tonne capacity!

I sent LDS an email requesting locker suitability guidance for an NQR.

I will let the forum know what LDS tells me.

 

[Andy Hino]

The guys at LDS are great and Im sure Norm will look after you
The issue is that there is 3 diffs listed that could fit, so you will really need the axle code.

I tried to have a look at the archived Isuzu Australia spec sheets for a 2006 NQR to try and get some kind of guidance, but could not seem to locate a spec sheet that would help.
Will have a bit more of a look and see what I can find

Edit: Ok, so I found this manual which may be applicable to you

NQR 450 | Manualzz

manualzz.com

Lists the rear axle as RO66 which is one of the axles LDS has a Nospin rear diff for.
Maybe check the compliance plate for rear axle code??

Andy

 

[sae8425]

Andy Hino –

Thanks for the link to the 2006 NQR spec sheet.

Somehow, I managed to miss that document in my searching.

The Isuzu Trucks Australia repository of spec sheets from 1974 onwards is a great resource to have available.

Whoever decided to archive all the old Isuzu forward control spec sheets deserves MUCH more than one keg of beer!

For others searching for information on older Isuzu trucks, the archive can be found here: https://www.isuzu.com.au/spec-sheets/

The "Compliance Plate" axle code is 6CP – and EVERY heavy truck specialist I've spoken with says this identification is useless.

Eaton evidently identifies No-SPIN lockers by axle manufacturer, not by vehicle manufacturer.

So, the axle code 6CP is useless for cross-referencing component interchange purposes here in America. Or so I'm being told.

I know for a fact that Dana and Meritor made at least some rear axles used in Isuzu forward control trucks over the years.

My problem is I don't know the axle manufacturer(s) that made the Isuzu/GM 6CP axle in 2006.

My research has also unveiled that different axle shaft spline counts and center sections were fitted to the 6CP model housing.

Pictures of NPR HD rear axles (which Isuzu/GM state is also used in the NQR/NRR/W5500) show center section casting numbers:

DVD 593

DVD 594

Heavy Truck breakers selling used examples of these axles (Isuzu/GM code 6CP) in America quote different axle shaft spline counts:

DVD593 – 19 spline

DVD594 – 20 spline

Was the RO66 / 6CP axle available in two different weight ratings? I don't know, but perhaps the shaft spline count indicates so.

Is only one of the centre sections suitable for use with a No-SPIN locker? Again, I have no idea; but Eaton seems to think not.

Isuzu spec sheets show the 1999 FRR RO77 rear axle rated at 7,700 kg, while the 2004 FRR RO77 was only rated at 6,500 kg.

Are there actual differences between these model year RO77 axles? I haven't a clue; but axle shaft differences might well exist.

There are also some internet drivetrain outlets in America selling Eaton No-SPIN #275S65 (w/ 39 splines) for Isuzu trucks.

However, NONE of these internet suppliers has been able to tell me which, if indeed any, Isuzu axle/truck this No-SPIN locker fits.

I read an apt quote attributed to President Abraham Lincoln recently – "don't believe everything you read on the internet"

Absolutely remarkable foresight!

I'm looking forward to hearing what LDS has to say.

Worse case scenario is that I have to graft in a Dana S135/150 rear axle (for which No-SPIN lockers are easily available).