How can I tell which chassis package my H3 has? The Z85 increased capacity or the ZM6 off road package? Are rear axle assemblies interchangeable between the two packages?

 

Glove box will have the RPO codes youare looking for.
If the glove box door was replaced the Adventure/Offroad package is easy to identify by a 285/75R16 size tire on driver door B-pillar.
The standard Z85 heavy-duty handling and trailering suspension was on non Adventure/Offroad packages.

 

Welcome to HF.

What year is yours?

All the rear axles themselves are the same: I5s have 4:56 gears, the 2008+ Alphas have 4:10 gears. Z85 had nothing to do with axles per se, except we know the Z85 did NOT have an Elocker. The Adventure/Offroad package has a small hole in the top for the electrical wire for the rear locker to run through. The axle capacity is the same.

Z85 was a GM bs lingo way of saying you got something special even though you do not have a rear locker or the off road suspension = you got the base level special stuff.

 

It's a 2006 and Im looking to get the rear axle assembly rebuilt or replaced and used assemblies tend to specify either ZM6 or Z85 so I didn't want to get one that didn't work.

 

Like Doc said the rears are all the same so you should have now questions on which way to go with the 06 rear...

 

Just find any H3 2006-2010 rear axle without locker from any I5 (3.5 or 3.7L) donor truck. You do have an opportunity to upgrade to a rear locker if that is important to you.

Or, if you have a local rear end/differential specialty shop, they can rebuild it with all ne internals fresh as a daisy. Not a cheap service these days.

 

Thanks to those for answering my post.