Forgot differential check

Just wanted to say hello to the forum from panhandle of Florida!

Now my problem...one of many...

I have a 2007 Tacoma crewcab 2wd/auto that I purchased new. At about 65000 miles I was told to perform a differential check but for some reason I did not.

The truck now has 118,000 miles on it and makes a metal on metal sound from the rear end when first starting out. When I get about 65mph, the truck sound in the cab with the windows closed is noticeable. At first I thought something is wrong with the muffler is often load enough to cause my ears to hurt.

I brought it to Firestone for a check and they cannot find the problem. Told me it is not the u-joints, not the bearings, my brakes are 65% gone, other than that good to drive.

When I left Firestone, noticed sound was gone. Got home and checked (for the first time) the differential oil (used this forum for information on how!). The oil looked brand new. I think they filled it up then checked for the sound, but I am not sure.

What I am wondering, how will I know if I ruined the rear end? What should I be listening for? Do you think it is okay since the oil looks new?

Last question, is it worth rebuilding?

Thanks again,

Love the Tacoma World Forum

 

Take the 3rd member out and inspect the ring, pinion, and spider gears. If there are noticeable chunks missing...it's ****ed

EDIT: Like this...this is bad haha (Sorry Brady )
http://www.tacomaworld.com/forum/2nd-gen-builds/249585-flying-krawler-3.html#post9643359

 

If you grenaded the rear end, you would definitely know. It would make a terrible sound and you wouldn't be able to drive it. If a simple fluid change solved the problem, just keep your eye on it and you're likely fine. I would have wanted to see the old oil come out though to see if there were any metal chunks in it as they are a good indicator of damage done. If your truck came with a limited slip differential, that could have been what was making the noise and the fresh oil could have been all it needed. TRD Sport models and some SR5 models came with the limited slip before 2008. At this point, I wouldn't take on the expense of rebuilding it as there might not be anything wrong. Just keep listening for the noise to return and deal with it if/when it does.

 

Did they say anything about the amount of metal shavings in the old oil or on the drain plug magnet. If the noise is gone and you don't hear clunking, grinding, etc; or feel anything slipping/hesitating when accelerating, my guess is you're good...I'd drive it until something noticeable appears.

If you want to put your mind at ease, you could put the rear on jackstands and with the transmission in neutral, spin the rear tires listening for sound and feeling for play. In that configuration, everything aft of the trans should spin/rotate. just my opinion, I'm no expert.

EDIT: Yeah, what Pugga said.

 

You are right,

It does have a sticker on the differential that says "LSD oil only".

 

Ding Ding Ding

 

In that case, make sure you put the correct oil back in with the fricton modifier, otherwise it will make a terrible racket. Even the gear oils that say LSD on them may not have the friction modifier in the oil and you'd need to add it. The incorrect oil, or oil without the modifier, could have been what was causing the sound. The clutch pack in the rear end is picky about the oil it takes.

 

They do not fix them self's. If a rear was making noise from lack of fluid the damage is done fluid won't fix it. More than likely your noise had some thing to do with the brakes and they dumped out what ever it was when they checked the brakes.

 

What is the friction modifier? Is this something I can purchase at an auto store? What exactly am I supposed to look for?

Thank you

 

Yeah, you should be able to find it at any auto parts store. It should be in a little bottle or package and it's a Limited Slip Additive. A lot of gear oils will say LSD compatible but may not actually contain the additive.

Check this link out, it's a whole DIY for the rear diff fluid change but shows the LSD additive used also since it was performed on a Sport model with the same rear end as yours:
http://www.tacomaworld.com/forum/technical-chat/24545-changing-differential-fluid-step-step-how.html

 

Thank you.