My 4runner has had a vibration in the rear end for a while and recently it got really bad. It only vibrates when are giving it gas and i only really notice it going about 30mph or so and higher. when it got really bad i looked at my third member and saw it is leaking really bad right where the driveshaft ends at it. My u joint is fine but when i wiggle the driveshaft it feels loose just inside the third. This isnt much information but if anyone has an idea of what is wrong that would be great. If it helps, I do have a Detroit locker in it with 4.88 gears but they have never given me any trouble.

Thank you,

 

The pinion bearing is bad, or the pinion nut has come loose, either way you will probably need to replace the pinion bearing and gears if you have been running it like that for a while.

 

Thanks for the information. How hard is it to replace the gears and pinion bearing? I have basic tools and Im not a mechanic at all but I have done multiple repairs on it.

 

You might want to look for a new third member. They can be found new for around $300-400 or used for around $100. IMHO just get a new one and bolt it in...a lot simpler.

 

It requires special tools, so you need to have a shop do it, or find a good used one some were.

 

I was thinking about just looking on craigslist for a used third but then I got to looking and its going to be hard to find a third with 4.88s and a locker. And if I got one without one of those I would have to switch my front or go without a locker etc... Any idea how much it would be for a shop to install new pinion bearing and gear and how much the parts would be?

 

Different shops charge difference prices, start calling shops in your area that can rebuild your third member and get several estimates, then go with the cheapest one.

 

Here are some parts for your truck. From new assembled units to just parts.

http://www.wabfab.org/Differentials/...-products.html