Issue Resolved

Hello All,

I have a '17 OR with 9K miles that has had the rear differential recall (they actually replaced the gaskets, etc.). They did this after I had already done the rear diff breather mod and no one at the dealership questioned anything.

All was well with no seeping but recently (about 4 months from the fix of the rear diff), I have noticed a bump/thump/clunk that happens seemingly randomly. At first it was slight enough that I thought I maybe ran over a bump or pothole, however, yesterday it happened again as I was reversing out of my driveway which has a slight grade (maybe 15 degrees) and the surface is flat. I don't know much about vehicles, but it does not feel like the transmission as it seems more rearward (based on sound and movement of vehicle when the issue happens).

I still have the 15K and 25K service for ToyotaCare left. I am trying to figure out if the rear diff breather mod I did (routed the tube up into the left tail lamp cubby and used the OEM tip that breathes for equal pressure -i.e. I did not use any type of filter on it to prevent dust or water etc.) is causing a problem via water or debris getting into the rear differential or if this is something else entirely? I am concerned that the dealer might blame the problem on the mod and I cannot locate the original parts...

TLDR: clunk noise towards rear of vehicle with slight bump felt in vehicle when driving at slower speeds (below 30mph) in both reverse and forward that occurs maybe a few times a week - is it related to the rear diff breather mod I did or something else?

Thank you for any input.

 

.

 

First Tacoma??

It sounds like the classic "Tacoma thud/thunk". If you search it you'll see like a thousand posts about it going back to the first gen tacomas.

Only real "solution" other than just ignoring it is adding weight and possibly an AAL. I noticed the thud went away on both my previous Tacoma's after adding a shell (weight), my new 3rd gen sort of did it but became less noticeable after my bedrack and weight in the bed.

You can check your u-bolts to make sure they're not loose but its pretty much a standard feature for tacomas... that and the "surge".

Edit: or this guys seems to think he found a solution, doesn't stop the axle wrap which is the underlying issue but does prevent it from causing binding in the slip yoke which is what the actual "thud" seems to be:
https://www.tacomaworld.com/threads/thud-thunk-lunge-lurch-stopping-started-axle-wrap-solved.230722/

 

I tightened my u-bolts and it got rid of the thunk I was hearing while going over uneven terrain.

 

It is my second one, but I didn't have the first one long due to some rodent activity. I did a fail attempt at a search that only netted one page of results for the "surge". Thank you for the clarification on this issue. I am not bothered by this at all but wasn't sure if it was a mechanical issue. I will check the u bolts per the recommendations. Thanks and sorry to post this ad nauseam.