Just changed my rear differential fluid..

Well if it's a bad u joint it can go bad instantly after a rear fluid change? I ask cuz I don't know. Because before I changed my fluid I drove to home depot, harbor freight, walmart, and then to get my trans fluid changed out. I also stopped by a fireworks stand and during the whole time it never made any noises. So I drove quite a bit then went home changed my diff fluid then the noise came(only in reverse). It did stop making the noise however and will continue to keep monitoring it until tomorrow when I top the rear diff fluid off with friction modifier. Then I'll continue to monitor it. If it is a bad u joint would it cost a lot to have fixed? I did find a high rating shop locally that works primarily on toyotas

 

If you do have a bad u-joint, it is in no way related to or caused by a differential fluid change. It’s merely coincidental and just has started doing it or you have only just now noticed it because you’re listening for any abnormal noises more so than usual. There should be no issues with the fluid you used, it should provide adequate protection to the gears. If the LSD doesn’t like the fluid, it will chatter and grab as you turn, you can hear it but you will mostly feel it. I used to have an 07 Sport with the LSD but it was a 4x4. My 07 would chatter and bind/grab on turns with synthetic gear oil even with friction modifier added. It only behaved with conventional 80w90 and a bottle of friction modifier. The u-joints themselves aren’t expensive but the labor to change them can be. U-joints are pretty easy to change if you are at all mechanically inclined, with the cost of labor you can mess up a few U-joints learning and still come out way ahead. I would replace the u-joints with greaseables (just my opinion) and check your carrier bearing while you’re under there. The carrier bearings are prone to going out fairly quickly on these trucks. Spicer U-joints are recommended.

There’s some good info in this thread.
https://www.tacomaworld.com/threads/1300-quote-replace-u-joints-and-carrier-bearing.502213/

And here:
https://www.tacomaworld.com/threads/u-joint-replacement-tutorial-needed.453021/

 

I mean you're probably right. I probably never noticed the sound til after the fluid change. I have always been attentive to noises (since my Corolla xrs has i/h/e/tune/after market clutch flywheel/pulleys /etc) and I'm ALWAYS KEEPING MY EAR for any unusual noises. But maybe this u joint noise got past me. I did read through some of these threads you sent me. And like another gentleman on here told me it sounds like a u joint. If it doesn't make that noise should I not worry anymore? It hasn't been today. But like I told others I'll add friction modifier and fill it til fluid dribbles out(I put more than 3 qts in already). I'm pretty mechanically inclined, so it shouldn't be too hard to replace. Maybe I can take it to the reputable Toyota mechanic shop for an evaluation then confirm it is a u joint (if the noise is still there) then I'll take it home and replace it myself with confirmation it in fact is the u joint (which sounds like it is) but again should I worry if the noise goes away? I felt like I was in the clear when I didn't hear the noise and I just went back outside to back my truck in and it didn't make the noise. I have a false sense of mind that my truck is OK


Thank you for your input

 

If a u-joint is making noise it would be best to go ahead and swap it out sooner rather than later. For one thing, it isn’t going to magically get better on its own, only worse until complete failure. It is also a safety issue, if it were to fail on the highway, it would likely render your truck inoperable (being a 2wd, you can’t switch to 4wd and get off the road in an emergency) and cease transferring power to the rear wheels, possibly stranding you in the middle of traffic.

If you do have a warranty that covers it, I’d go that route first and foremost.

 

I actually do have the truck under a warranty. And it does include the driveline and u joints/bearings pinion gears all that. But the only worry is they'll give me problems since I did the maintenance myself. And the warranty states all maintenance must be done through a dealership and have receipts to cover/pay for the work. Unless I just tell the mechanic shop I started hearing the noise and don't mention I changed the diff fluid. That way the mechanic can tell the warranty company it a bad u joint and I'll be covered

 

I should've mention this(probably going to open a can of worms) but I've had my lift for about a month. And maybe this is the reason this is happening to my u joint cuz the new angle. And that maybe I need carrier bearing drop. If so I ordered a carrier bearing drop kit from old man emu only 13 bucks

 

I thought the rear differential took 4 quarts. I have a 2016 and that is what the manual said to put in. When I did mine at just about 4 quarts it started to seep out.

 

It seems like I couldve put 4 qts in.. I'll have to put it on level ground and add the last qt or whatever it takes to dribble out

 

2007 manual says 3 quarts: https://www.toyota.com/t3Portal/document/om-s/OM35869U/pdf/OM35869U.pdf
2016 manual says 4 quarts with rear locker and 3.2 quarts without: https://www.toyota.com/t3Portal/document/om-s/OM04005U/pdf/OM04005U.pdf

 

Thats the manual I read 3 quarts for an 07..thanks for looking it up!

 

Have you been regularly greasing the u joints?

 

No zerks on PreRunner. They are run until worn out (evidenced by rotational backlash when twisting driveshaft by hand), then need to be replaced.

 

Sub'd for yet another thing to worry about. I've got 6 qts of

$30 Mobil 1 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

Mobil 1 75W-90 synthetic that I might have to return.

 

Why? You don't have a mechanical limited slip differential like the 2005-2008 TRD Sport models did.

 

Oh. I do have a Sport, but I didn’t realize it was limited to those model years.

 

I am with @07 sport 4x4 U-joint is bad, coincidental that you did fluid change when it showed up. My 07 Sport did the exact same thing in reverse only. U-joint covered by Toyota. There was an Extended warranty coverage campaign on this exact issue. Bad news: your truck may be out of the window for Toyota to cover it. I'd let the dealer look at it and see what they can do.

 

Some PreRunners did have the zerks.
The later the model the less likely it is to have them, but some did have them.

 

Since you don’t have clutch packs to “chatter” you don’t need to “worry” as much.
Lots of guys with the open diffs and “brake” diffs have run synthetic with no issues.
It’s the guys with mechanical LSD that seem to to report the most issues.

 

Oh really? That's interesting! On 3rd gens, Toyota gradually removed zerks on 4x4 models as well. My TRD Off Road has zerks on the front driveshaft, but not on the rear. It doesn't ease maintenance much, because the front driveshaft zerks are the ones more difficult to access with skid plates installed.

 

I didn't see any zirc fittings on there. These models of Tacomas don't have them I guess