Toyota Rear Differential Saga

Joined
Sep 18, 2002
Messages
6,056
Location
VA
My story started summer of '22. I replaced the rear diff cover on my '02 4Runner. Looked great, excellent welding. For whatever reason,
the mechanic that was doing the work somehow didn't fill the diff properly. In about 500 miles I started to hear bad sounds from the rear end.
I checked the level and drained the fluid and it was black as tar (it was a very widely known 75-110 brand). Mechanic admitted he made a mistake.
Agreed to fix it. Patiently waited a couple of months. A few texts here and there. Nothing. Decided to be more proactive.

Timmy the Toolman had a video of ECGS and how he was working on a 4Runner Rear Diff. I liked what I saw. Contacted ECGS and got it set
up to replace my Rear Diff. I proposed to the mechanic that he pay half of the new diff and I would pay other half and for the install.
I chose to let ECGS do the install. Hey, I figured they should be experts and know what they are doing. Let them do it all.

I followed ECGS's instructions to the T. Driving home I would pull over and let diff cool down all the way from their shop to my home. About a 3 1/2
drive one way.

First of Feb as I am greasing underneath, I notice the left rear backing plate is wet and the tire shows those wet strips and around the edge.
Like something has been slung off the tires. I smell it and it is gear oil. I immediately check my gear oil level and it is good.

Took to my new mechanic to confirm the rear seals are leaking. He said ECGS should have been replaced the seals when replacing the rear diff. He said he always gives his customers the option of replacing the seals even if they aren't leaking. Within days, my right rear is now wet.

Contacted ECGS and they said they always replace seals on a Chevrolet but rarely on a Toyota. But since it was leaking to bring it back in
and they would replace seals at no charge. Just a day of vacation for me, LOL. My new mechanic said to get drum brakes and 2 backing plates
as well. Brakes were soaked in gear oil and the backing plates were too rusty. Told ECGS about the brakes and backing plates and my free
seal replacement went to $2100 for them to do the job. I got upset and they finally agreed to refund me $200 of the original $1350.


I just got it "all" replaced today for $1800 total. Toyota OEM parts were $1000. From the diff to the drums were replaced.


What is the moral of this story?

Make sure your diffs are full.

All mechanics are not created equal.
 
Had a tiny pinhole at top of cover. You could see it was damp.
 
I thought the cover was welded on those. Coukd the pinhole have been plugged somehow from the outside? There’s not exactly pressure in there.
 
I have to wonder, if the seals went from heat damage… but its an unknown here. But if the backing plates were shot anyhow… Wonder if the seals and stuff were not on their last legs anyhow.

This much rust? what does the rest look like?
 
The mechanic that rebuilt the diff had to pull the axles to remove the diff carrier. Not sure why he wouldn’t have replaced them then. Are the axle bearings pressed on?
 
There goes
I thought the cover was welded on those. Coukd the pinhole have been plugged somehow from the outside? There’s not exactly pressure in there.
it is. JB weld was discussed. It wasn’t that expensive to do it right.
 
I have to wonder, if the seals went from heat damage… but its an unknown here. But if the backing plates were shot anyhow… Wonder if the seals and stuff were not on their last legs anyhow.

This much rust? what does the rest look like?
I could’ve reused the backing plates. My mechanic suggested that for $200 I should replace them both. We did wheel cylinders, too.
 
The mechanic that rebuilt the diff had to pull the axles to remove the diff carrier. Not sure why he wouldn’t have replaced them then. Are the axle bearings pressed on?
That’s what my mechanic said. I know he mentioned a press and how difficult it was.

I think that is why they offered to do that for free. I’m thinking ECGS feel they goofed up.
 
There goes

it is. JB weld was discussed. It wasn’t that expensive to do it right.
Maybe I misread the story. Sounds like the diff was ruined from low fluid which would have been prevented by plugging the hole proactively. Did I miss something?
 
Maybe I misread the story. Sounds like the diff was ruined from low fluid which would have been prevented by plugging the hole proactively. Did I miss something?
Yes. Diff was never low on fluid until the rear cover repair. Mechanic failed to fill and check properly. He told me he goofed up.

This was just leaking enough to make a dime sized wet spot on the top of the diff. I was trying to be proactive. LOL

$3000 + later....:cry:
 
I have an old habit looking under our Jeeps often at all the places where diff fluid, transfer case fluid & trans fluid could leak. It helps prevent problems. One of the bad things about people never doing their own oil changes is you never notice small leaks before it’s too late.
 
The mechanic that rebuilt the diff had to pull the axles to remove the diff carrier. Not sure why he wouldn’t have replaced them then. Are the axle bearings pressed on?
Yes they are, and the tone ring is a 50/50 sacrificial part when pressing them off, requiring $75 each to replace. All has to come off for new seals. Toyota also uses sealed bearings on their axles, which don’t get to enjoy circulating diff lube. Idk why they do it this way.
 
ECGS labor rate to me was $144/hr. I’m picking, but that ain’t exactly what I would call “tedious”.
:)
 
By diff cover are you talking about the axle housing? 🤔

But yes, what a **** show! Hopefully it’ll be trouble free moving forward
 
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