Portos

Alright so here is some back story to my issue. Me and some buddies out here in New Mexico were wheeling the Rio Puerco not to long ago and I got myself (in a completely stock 00' 4Runner limited w/ grey wire mod) into a sticky situation. Instead of using my better judgment and turn around I said what the hell and tried to do something well past the capability of a stock 4runner. The front was bucking pretty fierce during this one incident and I came down very hard. This jolt caused the front end to start popping very badly in 4 wheel drive only. The dash light will stay engaged and everything seems to be fine in 4 wheel until there is any load on it at all. I thought this could potentially be my half shafts until yesterday. I put it in all time with the button on the pavement, set it into drive and just rolled forward slowly while turning to the left. It pops very badly and almost seems to bind then unbind. Under further investigation I had a friend perform the same thing while I was watching drive shafts to see if a U-joint was bad and the front drive shaft would be going fine then without any acceleration at all the shaft would speed up by itself causing the front tires to jolt badly then the drive shaft would slow down again as if it were needing to catch up to itself. Well this leads me to believe that now I'm getting into some gear issues. The problem is....I don't know where to start. Transfer case or front assembly? The weather is changing quickly here in Alb. and I need to not waist any time on fixing this. Any suggestions? We luckily have a U-Pull it down here so parts really aren't an issue and they are dirt cheap. I just don’t have enough knowledge to be able to point out the damaged spot without just ripping into random things. Any advice is welcomed.

meisentones

With it in 4WD & neutral (parking break on $ wheel chocked) jack up the front end, and start turning things. Spin DS wheel and PS wheel should spin opposite direction. At this point you are only spinning gears in the front differential If it binds, then something in the front IFS is off. If no bind it could still be a problem with the pinion gear, since it is not spinning when you were turning wheels in opposite direction. Next, get under the truck and either try to spin the driveshaft of have 2 friends spin the front wheels in same direction at same speed (slow). It will probably spin most of the way then stop, then spin the opposite direction and then stop. Watch/feel/listen for binding in either the front third or transfer case.

My guess is chipped a tooth in ring or pinion gear, but could be a number of things. Just get it off the ground, and start spinning different things, with different setups (truck in 4WD & Neutral; 2WD & neutral). Jack up rear to and do 4WD and in gear.

Easier to diagnose with manual hubs, but you'll get it.

Good Luck!

Portos

Thanks for the advice. I'm going to give it a shot this weekend and see what is going on. Being that the vehicle 4wd is vacuum assisted should the truck be running during this diagnosis or can I turn it on, shift into 4wd, then turn the truck off so I can pinpoint noises better?

Portos

Alright so I performed what you had suggested and I am almost positive now that it is a chipped gear either in the pinon, carrier, or spider gears. I ordered an oil sample that will send out tomorrow to diagnose what kind of metal if any is in the front diff. Plus I borrowed a friends snake camera that has a light attached to it so I'm going to peak around in the drain plug hole and see if I can see some carnage. Hopefully its not to bad