Toyota FJ Cruiser Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Vehicle:
2007 FJ Cruiser
80k miles


Well,

I had my pinion bearing go bad a second time. It's been less than a year since I had it replaced.

I'm pretty frustrated at this point.

I had some very loud noise coming from my rear end so I decided to take it in to have it looked at.

Toyota wanted to replace the entire rear differential for an absurd amount of money so I took it to a local guy who tore it apart and determined it was the pinion bearing.

Bam! Noise gone, sounded great.

Fast forward to about 2 months ago I start noticing the noise again. Getting louder every week. I am driving a lot more. My commute went from 10 miles a day to about 60/65 miles a day back in March (Shortly before it was replaced the first time)


The only thing I can think of that I do differently is I tow a big camper around occasionaly. I went on a long trip in July. I weighed the camper (fully loaded, water, supplies, etc) and it was 4600lbs (yikes, the gas milage!)


So, my local guy has my truck again right now and is replacing the bearing again because sure enough, that's what it was.



My real question is what is causing it to go so bad so fast? This can't be normal.



Any input?
 

·
Registered
Joined
·
3,101 Posts
Vehicle:
2007 FJ Cruiser 80k miles

Well,

I had my pinion bearing go bad a second time. It's been less than a year since I had it replaced.

I'm pretty frustrated at this point.

I had some very loud noise coming from my rear end so I decided to take it in to have it looked at.

Toyota wanted to replace the entire rear differential for an absurd amount of money so I took it to a local guy who tore it apart and determined it was the pinion bearing.

Bam! Noise gone, sounded great.

Fast forward to about 2 months ago I start noticing the noise again. Getting louder every week. I am driving a lot more. My commute went from 10 miles a day to about 60/65 miles a day back in March (Shortly before it was replaced the first time)

The only thing I can think of that I do differently is I tow a big camper around occasionaly. I went on a long trip in July. I weighed the camper (fully loaded, water, supplies, etc) and it was 4600lbs (yikes, the gas milage!)

So, my local guy has my truck again right now and is replacing the bearing again because sure enough, that's what it was.

My real question is what is causing it to go so bad so fast? This can't be normal.

Any input?
Two issues here:

1. Setting up correct bearing preload and obtaining the correct gear contact pattern in a differential is very much a high-tech art. It can be very time consuming to do correctly, and you have to know EXACTLY what you are doing. Otherwise, guess what, the differential will fail again in a very short time. Most dealers will not attempt to rebuild or replace a bearing in a differential, they just don't have the expertise to do it correctly (as well as it was originally done at the factory). That's why there are only a few "specialist" differential builders who will warranty their work.

Rebuilding a differential correctly takes much more than just carefully "replacing parts", it's about having all the special tools and the skills for making measurements and adjustments to a precision of less than one-thousandth of an inch.

2. Once there has been a bearing failure in a differential, EVERYTHING inside the differential housing is contaminated with metal particles. A thorough cleaning would entail removing the entire rear axle from the vehicle, completely disassembling it, and hot-tanking it or flushing it with solvent to remove all bearing debris.

It's think pretty unlikely that your "local guy" has the expertise to correctly setup bearing preload and gear contact pattern after disassembling a differential; the rapid failure is pretty strong evidence of that. Time-wise, you said it was "less than a year" between bearing failures, but roughly how many miles was it?

Bear in mind that a correctly set-up differential, supplied with the correct lubricant and kept free from contamination will last 300k or more miles.

And, why did you wait until you had a "very loud noise coming from my rear end" before having it looked at? Every "new" noise is trying to tell you something, whether it originates in the engine, transmission, differential, etc. If you would have had this checked out & repaired at the very first hint of a new noise, you probably would be better off than you are now.

The best option is probably to purchase a complete, rebuilt 3rd member from a reputable differential specialist, or buy a complete new 3rd member from Toyota, and have it installed by someone who knows how to clean out all debris from the differential housing. Or, slightly riskier, buy a complete rear axle from an FJ that was in a front-end collision, etc.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
The 'local guy' does lots of differential work.

I should have been more specific. It's a transmission shop that is pretty reputable. It's a pretty big shop with 8 stalls and keep pretty darn busy.


I would say I put on about 20k miles since it was last an issue. Perhaps 25k.

As far as the noise goes, I had not noticed because it gradually got louder and louder and I just adjusted to it. At the time it sounded like road noise.

Since it's been fixed however I have been much more alert, so this time I brought it in pretty early.




Everything else aside, why did my bearing go bad at/around 50k miles? If it should be lasting until 300k why did it fail the first time?
 

·
Banned
Joined
·
9,090 Posts
I know the OEM pinion parts use a crush sleeve pinion spacer and any decent wack to the pinion area could further crush this beyond the amount needed for proper pinion spacing when setup. Thus loose parts. Any chance your off road habits or a situation or two have allowed this happen?

ECGS makes a solid spacer to replace this. Maybe see about uing one of these in your next rebuild??
TOYOTA 8' SOLID SPACER
 
1 - 4 of 4 Posts
Top