New gears.... REM polish worth it?

Anyone have experience with the REM polish on gears? SDHQ offers it on the gear kits for an extra $250. Trying to figure out if it’s worth it... the website says

“REM treatment results in a smoother surface. The end result is less friction, less heat, and less wear. Any machined part has high and low areas left over from machining, grinding, etc. Those high spots become the initial contact points which in turn can become localized hot spots. Those localized hot spots can take the temper out of the heat treated area of the surface and then become a pit. REM reduces that possibility.

Other benefits include elimination of stress risers on the edge of parts and less friction on any metal on metal surfaces.”

Thoughts?

 

This process is called "lapping". Here is a link to Crown Gears explanation of manufacturing processes: http://www.racegears.com/lapping.html

My takeaways from Crown's summary is that "lapping" the gears is a common step in the gear-making process for a precision fit of the gear set. They say that lapping may be over used by some manufacturers to avoid large investment in precision machines that minimize manufacturing defects. While it levels the manufacturing defects that can become "hot spots" and pits, it is also wearing off the case hardening all over the gear surfaces, and that has to result in shorter gear service life. If the vendor is supplying quality gear sets, I would have to ask why lapping is extra cost if it's necessary.

 

That’s great info. Thank you!

 

You didn't read far enough:

What I would like to know is if you really don't have to break them in if you get the REM polish. I asked Nitro, but this was their response:

Nitro lists a VERY extensive break in process. I would like to get the REM polish so I don't have to break them in, but I'm waiting for Nitro to answer about how that will affect their warranty.

 

OK, so the REM polish is more like a "Lapping Lite"?

To me, all this does is beg the question: "How does Nitro's (and other aftermarket) gear sets compare quality-wise with Toyota's original equipment differential gear sets that require no exceptional break-in procedures; e.g. "No towing for 500 miles, for the first 1000 miles "Do not drive at extremely high speeds", "Do not drive continuously in low gears", "Do not drive at constant speed for extended periods". And, yet these OEM gear sets last 100s of thousands of miles? With all this special treatment, just HOW LONG will an aftermarket gear set last?...And, will that service life be so long as to be irrelevant to a normal human lifetime?

I must be missing something here.

 

REM is a tank of fluid with little ceramic particles. They blast ultrasound into the mixture and it basically polishes off the microscopic high points on the surface. Supposedly those high points create heat, which fatigues the metal, which creates a pit, which leads to failure. Thats why nitro wants you to break them in, to wear off the high points without heating them up.

As for oem, my guess is that the tolerances are much lower so the high points don't create hot spots. I have my diff replaced under warranty and toyota told me just drive it no break in. I have 30k hard miles on that diff now

 

Thanks @osidepunker. Good info for me and the OP. REM Polish is nothing like lapping. It's like cleaning jewelry except with an abrasive. I wonder how much tank residence time is required on average to accomplish the desired result, i.e. a specified RMS surface finish?

Fascinating subject for an engineer with some exposure to industrial gears. Being naturally skeptical, I wonder if aftermarket manufacturers aren't (1) specifying rigorous break-in procedures to eliminate possible problems with their gear-sets and warranty exposure (Not unreasonable except why is special treatment necessary?), and (2) Up-selling the REM polish option for additional money as an insurance policy to eliminate owners ignoring the specified break-in. All very interesting.

 

Nitro recommended I do not waste money on the REM

But I'm going to do it anyway and probably just do a minimal break in.

 

How’s the break in going?

 

They get installed on Monday!

 

Awesome. Hope everything turns out great!!!

 

What gear ratio you opting for?

 

I inquired into REM polishing when I bought my 5.29’s. A local gear shop told me the same and to not opt to get it done unless I was racing the truck. I’m at roughly 300-350 miles into the break in process and doing great so far!

 

Break in is mostly important on cheap gear sets. Most quality gear sets are run in with the lapping process to create a smooth area for the contact pattern. Set them up to the specs that they were lapped in at and they will be good to go.

A few heat cycles is what's best for initial use. The REM polish is going to provide any noticeable enhancement for 98% of the uses.

You don't see trophy trucks driving around for 500 miles taking it easy before a race.

 

So I got mine REM polished because I won't have time to break them in before sedona. I was hoping that getting the polish would help if I don't fully follow the break in process.

Do you think I will be fine if I just drive it to work a couple times before the trip? My commute is 40 miles one way, mostly freeway. I can probably get in 2 or 3 drives to work and back but thats all I'll have time for.

What about the front gears???

 

You will be fine, just try not to sit a constant speed for a long time on the freeway. Vary it a little and you will be good to go.

 

With the REM polishing, it does not need to have a break in period which is why we offer it that way. A lot of people can't afford to do it as we have had people driving from rural arizona areas as well as out of state for us to do them. You can pull out of the parking lot towing a trailer, doing a burnout, on your way to the trailer, whatever you please.

With the REM polishing, you don't need to do the gear heat cycling of driving 50 miles, let cool, etc. Most people think that gear break in period is a "recommendation" and not a requirement which resulted in people paying for gears twice. The amount of metal in the first inital 500 mile fluid dump was dramatically less. Every gear company is going to say that you don't need the polishing because if people had to do an extra step, why would you choose that gear brand over another? All of our gears ship directly from Nitro to our REM polishing company and then to us. It ends us cost customers more money if we do the break in period for them rather than doing the REM polishing.

 

Here in a REM polishing pinion gear

 

Really? So I can just drive it like I stole it immediately??

 

Yes. Still recommend doing a fluid drop at 500 miles though.

 

Hey man, how's the REM polished gears treating you?

I just sent my 5.29 for REM and cryo, want to see if its true that it reduce break in period.

 

Machinist here with a machine shop, I would venture to say that Toyota had state of the art equipment that can produce a finish that requires minimal break in time. Machine rigidity and tooling are most likely responsible for this. An after market manufacturer would more than likely not have this luxury as the equipment and tooling would be very expensive. FWIW, this is just my guess as gear manufacturing is a specialty just as grinding, honing, or forging are. Not as common as say milling and turning are, my specialty.

 

Where did you end up sending them?

 

Hey Chad, I sent them to https://www.racegearbox.com/ , they are local to me , getting rem and cryo, just in case I go Harrops.

 

Looking forward to how it goes.
Still waiting to install mine.
The less downtime and break in, the better.
Hoping to find someone close.

... I have gotten front and rear bumpers and some sliders, so, I’m not lacking stuff to do.

 

Been a year or two and no issues. I beat on The Truck and gears are running just fine. I had the axle housing replaced last year and gears looked brand new

 

The lack of lengthy break in alone is worth the extra costs.

 

Agreed. I literally drove 500 miles through Baja like a day or two after installation. In fact, I drove 80mph for 60 miles when I picked it up from the gear shop

Btw, The Truck weighs 8000lbs. Trust me, those gears are getting a workout

 

8000lbs? What do you have done to your truck to get to 8k? I'm just asking because I had my 21 crewmax weighed and it came it at 5900 with 35's and full tank of gas

 

Hahaha check my build thread. I have everything plus the kitchen sink. Literally