90 runner 4wd problem
 

So im new here b/c I just got my first 'yota, a 1990 4runner:banger:. Anyways when in 4wd it sometimes make a weird rumbling noise like somethings rubbing. not really a grinding noise. it also vibrates a little bit. but if i stop or slow down to like 5mph it goes away. Any ideas? Also im looking for a good site to get parts for it from. I wanna lift it 4-5 inches and do some other stuff in the spring time. Thanks!

I found my rumbling problem to be the transfer case linkage that needed to be greased up and tightened. There's more info and description of the problem in this thread. Not sure if that's the problem you're having, but if so, it's an easy fix.

It could also be a driveshaft u-joint starting to go, or one of your flanges either on the diffs or on the transfer case, that is loose. Grab the driveshafts and try to shake them up and down to see if there is any play anywhere.

For your lift, IFS Toyota's don't typically enjoy being lifted 4-5 inches. Your CV angles will be a little excessive even with the diff drop kits that you can buy.

it could be a few differnt things front drive shaft u-joints maybe bearings add going crazy sounds to me like its speed though are you sure the 4wd is kicking in when you go into 4wd or not

Well I picked this rig up for 800 bucks, and I really havent found all the pblms yet. Too damn cold to work on it for any extended period of time. I'm not quite sure the 4wd is kicking in though. It feels like sometimes it works and sometimes it doesn't. Like I said im a total noob when it comes to yotas, so I appreciate all the advice you guys can give.