Binding sound when accelerating in straight line

I’m not sure if the chain has slop in it but only overcomes the gear I fits on under lid we may not, while the front shaft was out I had to have the center locked to get any power to the rear cuz the front flange would just spin since nothing was attached to it, it makes a noise like a bad bearing but much quieter, I thought maybe it was jus the sound of the bolts moving through the air quickly but when I remove the front shaft again I’m going to really pull on the front prop shaft and see if it feels like a bad bearing. According to another post where they had to replace their chain it only takes a few mm to make it skip. I’m going to wait for a warm day and take the case out and open it up and see if anything’s loose or the issue is obvious it it’s repairable I will try and salvage it but if not I will swap in another. I will take pictures and video of opening the t case since theres really not a lot of info on the tcase like ours, plenty of the v6 but it’s different since it doesn’t have the center locker there’s a whole planetary headset in ours that’s not in the v6 so I will thoroughly document the process! Thanks to everyone for their input. I’m going to focus on changing the timing belt next, wish me luck!

 

I just got under and spun my transfer case. It's just like you described it, mine has a bad bearing sound as well. Continuos scraping as as I rotate it regardless of position. The front axle does not make this noise as it's rotated.

Does a bad chain make this noise? I'm asking because I've never heard what a bad chain sounds like. Just want to be prepared, I'll probably order a chain instead of an entire transfer case if that's the issue.

I'm going to drain my t-case and examine the fluid. I topped it off but never drained. I'll post pics of what it looks like.

I've read that an under lubricated t-case can cause chain stretch in rare cases it seems. Makes sense since my t-case developed a leak and god knows how long I drove with it with less than a cup of gear oil. That was awhile back though. So it might be unrelated.

It seems it was about half full when I topped it off last time. The manual states the capacity is 1.5 qt so I had ~0.75 at remaining. Maybe that was the straw that broke the camel's back.

 

Just to add prior to this I had only spun it with the axle attached and I didn't hear a thing. With it off I was able to rotate it faster by hand with the bolts only. Very easy to hear.

 

Same here I just got done trying eight just the front axle and diff lock had to be on to spin the front shaft but it sounded exactly the same as before. I’m not sure what a stretched chain sounds like since I couldn’t find an Audio clip but it does sound kind of like the chain trying to move the front output gear and slipping then catching then slipping. “Jimmy dean” whatever u do so NOT take the actuator apart. I didn’t know it had a timing to it and disassembled part of it now I’m struggling to retime it total pain in the ass. Also our situations are almost identical so the issue is most likely the same for both of us as I too had only a handful of fluid and for who knows how long.

 

Thanks for the heads up! I most definitely will not take that out. We do have the same problem, I'm sure of it. I listened again and I retract the scraping sound. It sounds like a bad bearing though but I can't tell if I'm hearing gears or a chains.

I drained the t-case and ruh-rohhh. Here's the drain plug. The oil glissens with metal shavings and is rough when rubbed between fingers. The most telling sign is the globulous layer of shavings I circled in red that settled in the bottom.

This can't be good.

 

I scooped it out with a q- tip and this is what was inside. The circled part are metallic solid flakes.

 

After browsing through split transfer cases I realized that there's a bearing attached to the output shaft leading to the front axle of the vehicle.

Given that mine sounds like a busted bearing then it's not unreasonable to assume it is. It has all the traits when I rotate it. Sounds just like my right rear axle bearing when it went. The bearing has failed and the balls are grinding away leaving me with lots of metallic shavings and large flakes.

 

Any update???

 

Not for me, I won’t have a chance to take the tcase out until it gets warm so I’m idle on this issue till spring, but I will update this thread if I find anything between now and then! Again thanks for everyone’s help this was a weird issue and because of u all I think we’ve got it narrowed down pretty well!!

 

I am gathering the tools and parts necessary to complete the job. The output shaft bearing is en route along with an output shaft seal. It is recommended to change the corresponding seal after changing the ball bearing. Over time a leak at the transfer case motor actuator has developed and I will be swapping the necessary seals as well. Since I will be doing the job by myself I will also source a transmission lift from Harbor Freight to drop the transfer case.

However, being that it's the holidays and the 4Runner is finally drivable I am going to take advantage before putting her out of commission again. Realistically, I will probably get the ball rolling in January. Until then I just have to be more cautions in the snow with power only going to the rear wheels now.

 

A bearing puller will also be necessary and it looks like it's an interference fit so I will need to figure out how to press the new bearing back in.

 

We’re any solutions reached for this issue? I know this is an old post but I’m having the exact same issue with my 2004.

 

Joshua - inquiring to see if you were able to resolve the problem with the popping? My 2004 just started this.

 

Hey guys wondering if anyone has found the issue as I am now experiencing the same thing as well.