2018 Rear Diff Leak (SOLVED)

Hello Tacoma World. As most of us know (and for those that don't) these 3rd gens have a serious rear differential problem. Whether it's called a weep or a leak a $40K truck especially brand new ones should not be having this kind of problem. I first noticed my leak back in April 2019 with less than 15K miles and immediately thought the worst. After a quick search on the internet to see if anyone else had this problem I soon realized I was not alone. My first question was what is causing the leak? From what research I found the nuts/bolts were not torqued properly from the factory. It seemed like a simple fix, tighten the nuts/bolts. For those still under warranty like myself, this could be a risky task. Shearing the bolts was my biggest concern so rather risk voiding my warranty, I made a trip to the dealership. My first attempt at informing the dealership of my problem ended rather quickly. They assured me there was no leak by saying, "it's just blow-back" cleaned off the visible diff fluid and sent me on my way. Needless to say just a few short weeks later the leak was visible again. A second trip back to the dealership and now they agreed it was a leak. They replaced the seal and sent me on my way. A few more weeks later the same leak was visible and yet a third trip to the dealership but this time they claimed there was no leak saying, "it's just staining." Feeling like I was getting the run around with every excuse they could come up with I assured them I would be back with the same visible problem. One week later I returned to the dealership for a fourth time and requested to speak with the service manager. I informed him about my ongoing problem and he decided a new diff was the next option. A few weeks later after the diff arrived I made one more visit (trip #5 for those that are still counting) to the dealership. I requested to inspect the new diff before I left just to give me some piece of mind (pictures included.) I was also able to speak to the technician who would be doing the work and asked if he could take pictures of the old diff after he removed it. He was able to do so and much to my surprise rust was visible all around the machined surface of the old diff. In my opinion this most certainly would prevent a perfect seal thus causing a leak. It's been just over a week now and no visible leak (fingers crossed.) Hope those suffering from this same problem will find this useful. Pictures of the leak along with the old and new diff are included.

 

Cool, but 40k is not a lot for a truck.
For perspective, 40k will buy you 29 top of the line iPhones lol

 

Are Tacoma rear diffs still made in Thailand?

 

You know there was a recall for this, right?

 

https://www.usatoday.com/story/money/cars/2017/04/27/toyota-tacoma-recall/100980084/

Curious as to whether this issue was resolved at the factory for the 2019 models?

 

Not for 2018s

 

It's only a matter of time then. Mine looked identical to yours before I took it in for the recall work.

 

I'm curious as to whether the replaced diff is still leak free. I doubt the original diff had rust on the flange when it left the factory. I'm thinking the rust began after it rolled off the line due to a poor seal of the gasket and mating surfaces, in which case it could have happened again to the new diff unless they used a different and better type of gasket. OP if you're still here would you care to check in on this? Please and thank you!

My '21 has this notorious "seepage" and it's pretty disappointing.

 

I wish this was the case, but seeing as it's still happening with new trucks today it seems the mating surfaces aren't flat enough after being machined or the gasket used is garbage. I say that because from what I've seen, there's a TSB that increases the torque applied to those bolts during installation, and I'd hope if there's a TSB it would have been rectified by now for new trucks before they come off the line.

 

Post #2019 on this link has 2 PDFs with lots of info on this problem back in 2017. Not sure if the TSB has been updated to cover later years.

https://www.tacomaworld.com/threads...le-loss-of-control-of-vehicle.488536/page-101

 

Thanks for the info. Interestingly, the first PDF specifically states the recall does not apply to any TRD Pro or TRD Off-Road vehicles regardless of year. But it seems the dealers are mostly giving in regardless of year or trim, because I see a lot of OR guys on here saying their dealers at least attempted to correct the issue. From what I've seen, in most cases they were not able to fix the leaks for longer than a few months, even after changing the gasket and nuts. I checked the NHTSA website and my truck has no open recalls.

I'm going to bring my truck to my dealership and see what they say. I honestly don't even know if it's worth the hassle if it looks like it's going to end up seeping again anyway. In that case I'd rather them not touch the thing.

The PDFs also give some clarity on the retorque on the bolts. Torque goes up from 18 lb-ft to 28 lb-ft if and only if the gasket is replaced and the nuts are replaced with a different variation.

Edit: Looked at different threads again and I think those that had the gasket and nuts replaced had some success. At least for longer than a couple months. Some reports of the dealer just checking torque on existing nuts and not replacing anything, well those guys it seems mostly ended up back at the dealership soon after. Also, looks like the dealership will usually address it regardless of year and trim if the truck's still under warranty. Makes sense.

 

I had the TSB done in 2017 and the weep has not come back.

 

That's good news. They replaced your gasket and nuts? It's incredible that 4-5 years later new units still have this issue.

 

Toyota retorqued the bolts. I was waiting for the weep to return, but maybe in hindsight for me it was good I did not push for them to take it apart.

 

Wow nice, seems like you got a bit lucky with that. I definitely agree that the minimal amount of intervention was definitely the best. Thanks again for directing me to those recall documents! I think I will try checking torque and cleaning myself first, and if it comes back I'll take it to the dealer.

 

2020 with 43000 miles. Dealer told me they would not repair unless it was dripping/ leaking.

 

Not hard to check the differential oil on these. If it's just mild seepage like that. Squirt a little diff oil in it if necessary.

I'm only suggesting this partly as a motive for myself, since I Fluid Film everything under the truck. I would never know if I had a diff seepage issue like that...

 

You need to be more persistent. The dealership just doesn't want to admit this is a problem. Ask to speak with the service manager and don't take no for an answer. Remember... YOU are the customer.