For those of you who are considering doing away with the torque tube and converting to an open driveline, the Colorado/Canyon/Isuzu "I" trucks gives us a rear-axle swap option in a 6-lug (6 on 5.50"), drum-brake-only package. There are different 3 different gear ratios offered, the Gear Ratio RPO codes are: 3.42/1 code GU6 3.73/1 code GT4 4.10/1 code GT5 All variants have a Hub Diameter of 3.960"(100.5mm) which is larger than the hub of the AD. Spring perches will need to be replaced for proper spacing and pinion angle. There are 2 different Ring Gear SIZES available as well: ___________________________________________________________________ The AAM800 has an 8.0" ring gear, and 28 spline axles. ALL 4- and 5-cylinder trucks 2004-12 have this rear end, the rear cover looks like this: The 8.0" has a relatively relatively straight plane from ring-gear bump to the right side, mine (an '04) has no fill-plug. VIN 8th digit 8 (2.8L L4) RPO LK5 2004-2006 VIN 8th digit 9 (2.9L L4) RPO LLV 2007-2012 VIN 8th digit 6 (3.5L L5) RPO L52 2004-2006 VIN 8th digit E (3.7L L5) RPO LLR 2007-2012 A 2WD, Z85 optioned rear has a WMS to WMS width of 60-3/4" (verified 12/09/15) I do not yet have a width for the 4WD. ___________________________________________________________________ The AAM860 has an 8.6" ring gear, and 30 spline axles. Only V8 trucks 2009-12 have this rear, the rear cover looks like this: The 8.6" ('09 shown) has a noticeable bump to clear the ring gear and curves back to flat on the right side, and a fill-plug. VIN 8th digit L (5.3L V8) code LH8 2009-2012 A 2WD (they call it 4X2), Z71 optioned rear has a WMS to WMS width of 63-1/8" (verified 1/3/2016) From what I can gather, 2WD V8 trucks were only available in 3.73/1. 4WD V8 trucks appear to have all of the ratios available. Differential types G80 is a Gov-Lok (a type of positraction) (look it up for more info) if G80 is not mentioned, it is likely an open-differential. In a stock I6 AD, the VERY plentiful 8.0" should be fine. If you are planning an V8 swap, and a Colorado rear end, the 8.6" may be a better choice. As a bonus there is much more aftermarket support for the 8.6". All that VIN code/engine info and RPO code info listed above is to help you at the junkyard (or www.car-part.com for an online junkyard search). For reference, a car-part search today 12/3/15 showed only 5 8.6" rear ends, NATIONWIDE (rare until more V8 trucks make it to the salvage yard), but literally hundreds of 8.0" If you have added a Colorado rear to your AD, and it was a 4WD donor, please PM me the width, and I will add it to this post. Thank you.