I've been searching and reading for a couple days now and I'm still not definitive on my issue, so I'm resorting to a post.

I took my 88 IFS 4Runner out wheelin last weekend. I took several steep grade descents with the truck engine braking in 4lo. After three hours or so, I started hearing pops that were loud enough to hear outside and inside the truck, sounding like it was coming from the front end.

You can hear the pops near the end of this video. The first loud one is when the front wheel drops off the last ledge (you can't really see the ledge) and a couple more as the rear wheel is right before the drop and right after. I THINK that is the same pop I'm talking about.

http://www.flickr.com/photos/ocell/7...in/photostream

Here's where things get confusing for me. I REALLY noticed the pops when my buddy and I were standing outside the truck surveying another descent. The truck was in 4lo, in neutral, with the parking brake on idling next to us. It did a few more of those pops with no pattern or obvious cause. Axles weren't turning, gears in the transfer case shouldn't be turning, right? I put it in 2WD and drove the trails out of where we were, and then an hour and a half home on the road and I never heard another noise.


1.) My CV boots on the passenger side half axle are torn. The pops didn't happen while turning, it was always a straight line, and even when the truck was stopped, so I don't think it's the CV joints.

2.) My propeller shaft had quite a bit of grease around the outside of the yoke. I'm wondering if it's low on grease and the pops were from the propeller shaft extending/shortening. When the truck was sitting at rest, maybe this shaft was slowly relieving tension and popping.


Does anyone have any thoughts?

 

take a video of it poping while just sitting.

 

I'll try, I've got to find an offroad area where I can load up the front drive system, I think. I let it idle in my driveway with 4lo engaged for a while and it never popped.

What are you thinking it may be?

 

 

its cause that boot is torn. mine does it too.

 

Torn boot + shaft not spining = noise

nonono that math doesnt work out.

Thats like your boat sinking on land

 

Yeah, I wish it was as simple as a worn CV joint.

I still haven't had a chance to put load on the front driveline to diagnose further. There aren't many off road opportunities in downtown Austin.

 

bet its your cv about to taker a dump.... try just locking one hub at a time in 2wd and see if it does it

 

Who are these people? Read the whole post would ya. He said that it makes the poping noise even when the truck wasnt moving. Just running.

 

 

Yeah, thanks for reiterating that the popping was happening while the truck was sitting still. It's a key element of why this is confusing me.