Oh, sure you can. Our corporate overlords blame us for not being perfect all the time. Then again, they get paid to administer that tough love stuff-keeps us on our toes and all. That said, we also know that we can always do a better job when it comes to testing new trucks and new products, and we always welcome any constructive criticism-and any surly rants, too-that our readers care to share with us about such stories, since they sometimes provide us with some insights that we otherwise might have overlooked. That "learning experience" you mentioned cuts both ways, you know.
GM Axle Answers . . . and Mysteries
I'd like to add a few unsolicited comments regarding Robin Stover's article discussing the GM 9.5-inch 14-bolt axle (Mar. '10). First, I'm thankful to see your magazine highlight a fabulous-yet-overlooked axle for the GM guys. I personally run one of these axles underneath my '96 Chevy Tahoe.
As for the accuracy of the article, the author overlooked plenty of opportunities to acquire this great axle. The six-lug, 9.5-inch 14-bolt is also found underneath 4x4 1988-98 GM 1500-series pickups with a GVWR of 6,600 pounds. Additionally, the same axle sits underneath both two- and four-wheel-drive configurations of the light-duty 2500 pickups for the same years. The key to finding the right axle for your 4x4 vehicle is to make sure the donor 14-bolt comes from a four-wheel-drive model. The 4x2 model uses a 65-inch wheel mating surface (WMS) to WMS, whereas the 4x4 model uses a 70-inch WMS to WMS for the '88-98s. I've physically confirmed both measurements.
Also, beginning in 2004, the 6-lug, 9.5-inch 14-bolt made a return in the Vortec Max 1500 trucks with the 6.0L (LQ9) engine. As a curious side note, there is actually a five-lug, 9.5-inch version of the 14-bolt found in the two-wheel drive 454SS Pickups built from 1990 to '93. Anecdotally, I believe some mid-'90s 2500-series vans also used this axle. Regardless, there are plenty of axles available for the enthusiast.
One final note: For my '96 Tahoe, I needed a Saginaw-to-1350 U-joint conversion to complete the swap. Hope this helps your readers hunt down a good replacement axle for their 1/2-ton trucks.
I have a 1968 Chevy K10. It has the 307ci V-8 with a four-speed tranny. The front axle is a Dana 44, and the rear axle is a mystery. I checked all axle codes on the Internet, but mine isn't listed. It has a 10-bolt diff cover. The yoke side is stamped "GM52." The top right forward tube is stamped "W A 0328," then "K OR W." Underneath the "A" is the letter R. When you spin the tires in the snow, the left tire spins immediately with the right and will not stop until the right does. What does the stamping mean? I assume I have a 3.73:1 ratio.
Oak Creek, WI
Argh, you would have to ask about older GM axles. They're among the hardest to identify of all the OE axles-outside of counting the number of bolts on the diff housing-since their ID stampings differed according to brand application (Pontiacs, Chevys, and Buicks, for example, might use the same rear axle, but each would have its own ID stamp), and the stampings often differed between model years, even if the same axle was a direct carry-over from the previous year. The most obvious answer would be that your truck has the Saginaw Model 52 full-floater rear drop-out, which has a very stout 101/4-inch ring gear. Unfortunately, this unit was only used in HD K20/30 trucks and has a 12-bolt diff housing. The next likely candidate would be the fairly ubiquitous 83/4-inch rearend that was used in a slew of GM car and truck applications in the 1960s-but again, it's a 12-bolt.