Will running a different size spare hurt the diff?

[absentmathis]

Thanks for the feedback fellas. Lots of good points - it's a short drive, people on both ends to help, etc. Only reason I'm giving it a second thought is that we've got a fairly new baby and none of us would appreciate being stranded tomorrow. I've actually never had a flat on the road in 15 years of driving, just figured I'd be prepared if possible.

Not sure about the wheel size talk, spares are often different wheel sizes at least from what I've seen. In fact I wouldn't give it a second though also if it were a 2wd vehicle. I was just wondering if running a different diameter would blow up a diff or transfer case in short order, and sounds like the concensus is that I'd be alright if I had to limp along. Cheers.