Ok before I even start I'll say this, If I could find a 205 I'd put one in!


I installed a part time kit in my 203 yesterday, everything went togeather well and I followed the instructions to a T.
Also if it makes any difference it's a 73-74 case with the solid carrier.

Put my driveshafts in today and when I'm in 2WD I get this crunching sound. Nothing like a gear clash or anything, it kinda makes the same sound as a really bad U-joint but they're all fine.

Strange thing is if I lock the hubs while in 2WD it doesn't make any noise or if I unlock the hubs and have the TC in 4 high it doesn't make the noise but as soon as I unlock the hubs and put it in 2WD the noise is there and only when I'm under power.

A friend has a 79 Chevy pickup with a 203 and he put his kit in back in 82. He says that after he put about 10k on it his started making the same noise.

Any ideas?

What brand kit? I have heard that the 73's and some of the 74's had some sort of clearence issue in the tails shaft. I have two trucks with the Mile Marker cheaper kit. The only thing I can think of causing you an issue is the not installing the thrust roller bearing between the diff carrier and the back of the front drive top chain gear. If it wasn't in there or the washers were not put on both sides then the unused Diff gear on the back of that chain sprocket might come in contact with something. The other possiblitiy is you installed the shims in the wrong place (very common). It is easy to think you need to put those shims between the yoke and the bearing when in fact they need to be on the otherside of the bearing so as to push the diff towards the front of the case. If they are put in the wrong location the the diff assembly would hit the tail shaft housing. You can also get the diff in backwards and you can get it assemble that way. Again the same issue. The diff assembly would hit the housing.
I personaly think it is something to do with that thrust bearing that comes with the kit since it goes away when you get the chain spinning. Reason is everything will now be spining the same speed. Only other thing I can think of is that the diff lock collar is not fully dis engaging.
Might come over to www.coloradoK5.com and post the problem. Lot more of us running them and better chance of finding somebody that has had the same issue.
Also another tip is over fill the hell out of the case. One of those gears is actually a pump that feeds the tail shaft bearing and forces oil up into the top chain gear roller bearings. it is supplied with oil from a resivior in the tail shaft. That was kept full by oil slinging off the chain. Over filling it will make it easier for oil to get into the resivior when you go up hills or make a hard take off.
I personaly think the 203 is a pretty tough case. Both of mine have close to 300k on them and other than worn out chain no problem. My 75 was full time till last year. Tetting 200+k out of a case that is always running is pretty good. I think the bad rep came from people that converted them and did not over fill and put into LOC every couple of hundred miles to get the resivior refilled. Then they burned the bearings.