Was told my rear differential is shot - time to regear?

So a few months after installing an Icon RXT Leaf Pack in configuration II, I started noticing a "clunk" noise that seemed to be in my driveline. I fought the service techs at the dealership for ages trying to get a diagnosis, and eventually ended up getting the diagnosis done at a third party garage (shoutout to CoAuto in Reno, who are amazing).

Long story short, they found metal filings in my differential fluid and suggested I ask the dealership about warranty replacement. The dealership told me that because I have an aftermarket leaf pack they cannot perform the inspection required by Toyota to perform a warranty replacement.

So now I am planning on having the other garage do the replacement work for me instead. My question is this: since they are already replacing the gearing in the rear differential, is it a good time to have the truck regeared? I figure since they will be doing half the work already, I could save myself some time and money vs. having this replacement done, then later regearing.

Vehicle info is as follows:

2020 TRD Pro V6 Automatic
16" Wheels with stock size 265/70R16
GFC Camper Shell adding ~200 lbs static weight to the bed

Thanks for any advice/comments.

 

I feel pretty confident that you could fight the dealer on that bullshit excuse, but if you're considering a re-gear anyway then it's probably not worth the pain and hassle. Consider it a good excuse to re-gear.

Going to 5.29's made the biggest difference in driving enjoyment for my setup. Depending on your driving style, it might be too much gearing for your tire diameter. But if you think you'll go up in tire size at some point, I'd definitely recommend doing 5.29's. If you're dead set 100% going to stay at the 265/70, then 4.88's would probably work better.

 

First question, did it have the iconic diff howl before the leaf pack was installed? Also remember that on a 4x4 you need to regear both axles. As for weather or not to do the regear, do you have shifting complaints? if yes a regear will help, if it shifts ok in your opinion than just leave it.

 

Absolutely time to regear.

 

Your best bet and usually the cheapest route is to buy a 3rd member from east coast gear supply and have a shop do the replacement. On a lift the rear takes about an hour to do, the front takes quite a bit more time. Using the lifts at my work I think it took me 5-6 hours to do both diff's including cleaning up and the first 15m drive cycle.

 

I'd be sure the rear diff is actually broken. Metal filings can be normal and don't necessitate a gear replacement. If there's a clunk you should absolutely be able to confirm it's the diff.

 

Thanks to everyone who has replied so far! To answer some of your questions:

If you're dead set 100% going to stay at the 265/70, then 4.88's would probably work better.
Unfortunately due to garage constraints I am pretty much maxing out my height limit on stock tire size. At the very most I may one day go to 265/75R16

did it have the iconic diff howl before the leaf pack was installed?
No noise before the leaf pack replacement - I swapped the leaf pack to accommodate the extra weight from the camper shell and to handle the gear I take on trips. The noise I started hearing recently was like a low thunk/clunk from the rear of the vehicle that generally occurred once while accelerating from a complete stop after a few seconds (maybe around 30 mph) and once again when decelerating.

do you have shifting complaints?
Absolutely. I live up in the mountains and find that the truck is constantly hunting for gears while climbing the steep hills I encounter on my daily drive.

 

If you have complaints do it, and don't look back

 

Not saying your diff is fine, but this sounds a lot like axle wrap or something. It's also coincidental it started after your rear spring swap. I don't like coincidences. Just be sure what you're going to go pay for is actually fixing the problem.

A busted up diff should make noises constantly.

 

Ya I had mine done and it had the howl. Afterwards I changed the fluid and there was alot of break-in metal from the new diff, even some chunks that looked like machining chips. Same in the front, had a bunch of stuff that must have been from the factory because it was the first time It had been changed.

 

Absolutely - I appreciate the voice of reason. Axle wrap was one of the first things I suspected and checked myself and I was able to rule it out. Not only were there no visible signs of it when I took video while driving, but the noise is reproduceable with the truck on a lift which means it's definitely not a wrapping issue.