I'm sure this has been beat to death but I just spent quite a while reading through posts trying to find some help and now I'm here. I did the CAD mod on my 91 XJ. Drove down the road and after about a mile I heard a loud grinding noise, sounded like gears stripping. I quickly reached down and pulled it up into 4 wheel drive and he noise instantly went away. I pulled over and pulled off the vacuum lines thinking it may have been trying to engage via vacuum and this did not fix it. Any ideas?

 

by cad mod, you mean manually shifting the collar over the two axle shafts and somehow locking it there via either a hose clamp or bolt to hold the fork in the lock position?

if so, i think something came loose and now the collar is grinding on the axle shaft spline.

when i was using a posi lock cable mod, it used to do that all the time. would sort of kick out of 4wd, till you pull the cable back into the lock position.

you should just look for a d30 with the larger u-joints and the one piece shafts and swap that whole axle in.

 

Yes, that's what I mean. I did the mod with washers. I'm not sure how it would slide back but that's my thought to is that it is somehow moving. I'm gonna undo my mod and take it back out to see if it fixes the problem. Just really need 4 wheel drive next week for hunting season. That's the only thing I use the jeep for.

 

Do it this way:

https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/

 

^^ Great mod to do if your not thinking on upgrading. Had this for a while until i changed the 2 piece axle to one

 

Did you do the washers? Im not too hip on just using the c clip.

 

Really? Clips are what held it one way or the other all these years...........

I've probably done 10 or so of them with no issue.

 

Yeah, I guess the washers just seem so much more solid. It obviously hasn't worked on mine so maybe I can try the clip.