CK5 - The Full-Size GM Off Road Community

I have finally gotten my 72 K/5 on (and off) the road, and just two weeks after starting to drive it, the pinion gear came loose, and fell into my rear differential. It had completely destryoyed my ring and pinion gears, and I was forced to make an emergency replacement of the diff with one from a 69 pickup to get the Blazer home. My main problem is, the ratio is different. The Blazer HAD 3.73 in it originally, and the diff that i put in is somewhere near 4.11. My question is, is this going to damage my driveline and/or transfer case? Will it help if i remove the front driveshaft untill i can balance out the gears(put the 3.73 back in)? Also, it has started to get a strong vibration underneath the truck at around 20-25 mph now that wasnt there before. Any suggestions?

Yes, remove that front driveshaft to prevent damage if you accidentally put the transfer case into 4...

That vibration might be due to a bent driveshaft. Has it been checked?

You say "somewhere near 4.11". You don't know for sure? I wouldn't be so concerned about the front drive shaft. It's keeping the hubs unlocked. Even if you pull off the driveshaft off, KEEP the HUBS UNLOCKED!

The vibration could be any thing. Here's the first things I would check: driveshaft (like steve said), universals. Chances are when the rearend was starting to lock up you cracked a universal.

Hey if that rear is 4.11 or so and your replacing them let me know I need a set that size for a 12 bolt. if they are in good shape

I plan to take the diff apart again tomorrow, and I'll find out exactly what the gears are. Other than that, I've got a donor truck with the 3.73's I need, so I'll be swapping them out tomorrow. I checked the driveline, and turns out the rear driveshaft had become slightly unbalanced when the pinion broke loose. I plan to get a new one as soon as I can find one for a good price. More news to come if I've got it...thanks for the input, guys.