Rear Differential Fill Plug Issue - FIXED

I'm already beating myself up enough as is it so please be gentle.

I successfully drained and refilled my front diff.

I either overtightened the rear diff fill plug turning it the wrong way initially when taking it off or somehow overtorqued it when putting it back on (only tightened to 36ft lb) but noticed it turned further when double checking.

The plug is pretty tight and is not what I would define as loose. It will not rotate by hand but will rotate again when ratcheting. It is now sitting at the tightest it will go without rotating again.

As a bonus, I haven't been successful in getting it out either but have only tried the vise grip and screwdriver method to back it out.

Since it's Sunday the dealer parts departments are closed. None of my local parts stores have one either. I tried looking online but I can't find the part number.

I'm planning on calling the dealer tomorrow to see if they have any in stock.

1) This is my daily driver and while the plug is pretty tight it could potentially leak oil and I don't want to permanently damage my rear diff. Should I just not drive or check for leaking fluid since it's the fill and not the drain?

2) Does anyone have the part number for this? I haven't been able to find one.

If you've read this far thank you. I don't post a lot but I do read threads because there's a lot of great information on this forum.

 

I don't think I understand your current situation. You put it back on and torqued it to 36 ft-lb, but doing that resulted in being turned farther than you expected? Is that with the original washer, or a new one? I'm not sure what you mean about rotating by hand vs. ratcheting - if it's at 36 ft-lb, that's what I would expect.

 

Yes, I used a new washer.

I may have damaged the plug before take off by overtightening since i was turning it the wrong direction like the idiot i am, or by overtightening with the torque wrench, I am not sure. I got plug tight, got one click on the torque wrench, went to click it and the plug was loose again.

My concern is that it gets fairly tight but then loosens again with continued turning and I don't want to lose the oil until we can back out the plug and replace within the next few days.


*edited for typo*

 

Not to worry bud. We all make mistakes and this is fixable. If it was me I would drive around the neighborhood for 5 to 10 mins. Then leave it running in your drive for 10 to let it get to a bit more temp. If no leaks, or issue I would just drive it until you get it to the dealer or you find the right parts. Don't beat yourself up bud. I have done it too.

 

It sounds like maybe the threads are damaged either on the plug or the differential. I would say whichever is the softer material. I wouldn't mess with it until you have another plug and washer in hand. And prayers that the threads in the case are okay.

 

Threads might be damaged from tightening it first, but I really doubt it’s gonna come loose. Just get a new one.

 

Drain plug tread is most likely is striped. Unlikely to have cast insert of a diff damaged. Get new plug and washer, tighten to specs and you are good to go.

 

and have a mechanic or mechanically inclined friend install it

 

Why? He might as well put the newly-one experience to work. It’s probably just the bolt. It’s better the mistake was on the rear diff instead of the cast aluminum transfer case. That for sure would end up stripping the threads in the case. Much gnashing of teeth and rending of clothes would ensue.

 

Yes this is my fear. I read on one of the Tacoma forums that the bolt material is softer than the case material so I am hoping it's just the bolt. I guess I'll see when I get it out.

 

Small update: I drove around town about 20 miles yesterday checking at stops for leaks. I did not see any but I'll be very careful to not put miles on until I can get it fixed, which hopefully will be later this week. I will be stopping at the dealership on the way to work this morning and I'll update after it's done.

Thank you everyone.

 

I shouldn't respond to this but here I go.

Yes, I will be fixing it. I made a mistake. I like working on my vehicles. I know when something is above my skill level, and ask for help from people with more experience when necessary. I'm capable of doing this and a lesson was learned.

*edited because I need more coffee*

 

Drive it as normal. Replacement crush washer is 1215710010. Replacement fill plug is 9034118006. Dorman 090042 works, too, though it takes a 19mm socket instead of 24mm.

Caveats about torque wrenches:
1. Some torque wrenches have high internal friction and don't click if you go slow. I snapped a wheel stud because of it.

2. Unless otherwise stated, the service manual torque specs are for dry threads, which for fluid plugs will not happen unless you're building up a new engine or axle on the bench. Just use a long ratchet (say 17") and give it a tug, that's it. You'll feel it when the crush washer compresses and the force goes way up. Stop tightening when that happens. I stripped a transmission pan drain plug relying on a torque wrench before I knew about this.

 

Thank you for the helpful info!

 

Driving around for 5 or 10 minutes will heat up the oil in the rear differential.

Leaving the engine running in your driveway for 10 minutes will do nothing but COOL the differential oil. The diff isn't turning so it won't heat up.

 

No need for Locktite on drain/fill plugs.

 

Wasn't the drain plug.

 

Fill plug, I know, same solution.

 

In for the fix.

 

Yep, I totally smashed the threads on the fill plug bolt but the diff case threads are okay!

Getting the old bolt out was a PITA. We had to heat it up and it still took both myself and my brother pulling/turning it with vice grips to back it out.

The new one went on okay but for next time I will:

1. Make sure I'm turning the correct way on take off
2. Have extra plugs on hand.

 

I'm glad it turned out OK.

 

Great news! Disaster averted.

I have made that mistake too, live and learn.

 

That is one issue that you will never encounter again...

Kinda like when I did my first drum brake job and tore both sides off at the same time. Never did that again...

 

Righty tighty, lefty loosey.

 

Congrats on getting it done!

Yikes! Vice grips?!?! Why couldn’t you use a socket with breaker bar instead? Was the bolt head rounded off?

As much as I like my 1/2 milwaukee impact wrench, I’ve learned to use it sparingly and with much more care, after my first Al Pachino style “say hello to my little friend” attempt to loosen a bolt…with it set to tighten.

Much better to make that mistake by hand.

 

The way that bolt looks, I'd guess that it probably wouldn't just screw out. It probably needed some outward force during the rotation due to the thread damage. I suppose you could still use a socket if you could work a wedge under the head at the same time.

 

Yes, this!! Unfortunately, there wasn't enough of a gap to get something behind the head to get enough leverage to get it out that way.

 

oh I get it. Yeesh, this was pretty bad then. Glad you got it done!

 

Some one mentioned impact wrench… Removing any frame bolts that could have rusty weld nuts with impact gun is asking for trouble. Those nut welds will certainly break off. Use breaker bar instead. Don’t ask how I know this.

 

Glad you were able to sort it easily.

Please add this to your list and remember it: ALL FASTENERS GET STARTED AND RUN IN BY HAND BEFORE USING A WRENCH OR SOCKET

This will alert you early to misalignment and damaged threads. Will also make it harder to make the problem worse.

"Hi, I'm Jason M, recovering gorilla fister"

Jason