Verifying best practices for gear break in

[mrblaine]

Interestingly I ended up on Bob is the Oil Guy and they will tell this is internet folklore because Currie and other companies would not share their testing data with them and that there is no way that synthetic oil is the cause of failure. What is being ignored to some extent is that after Ford retired the 9inch in 1985 the GL-6 oils they preferred were soon retired as well. This was also when synthetics were first coming onto the scene and since there was no call for GL-6 they just made GL-5. GL-5 does not have all the same additives that GL-6 did which are necessary for preventing gear scoring like in high offset pinions ala the 9. These same additives are also beneficial when running very low gears in diffs like the Toy 8inch, 14bolt and others where the pinion has more of a tendency to slide across the ring gear.

Isn't there a saying about trying to prove a negative? Just because someone won't share data does not make the conclusion of that data inaccurate. I chatted with John many times about that and it never varied. They warranty their rear ends. If they see a bunch of failures and determine causation between two different scenarios, one being synthetic and one being conventional, it doesn't take a genius to see what they will use to slow down warranty claims.

I also don't think many folks know that Currie actually built a gear dyno and used it for a bunch of things. One was to define the oil path onto the pinion bearings in the high pinion 3rds set up in fabricated and Ford housings. They had some clear plastic over areas so they could spin the gears both directions and watch how the oil got slung around. Same kind of stuff Banks did but well over 20 years ago.

Currie at that time had absolutely nothing against synthetics and said as soon as they found some that worked, they would use it.

 

[Blackjack]

Isn't there a saying about trying to prove a negative? Just because someone won't share data does not make the conclusion of that data inaccurate. I chatted with John many times about that and it never varied. They warranty their rear ends. If they see a bunch of failures and determine causation between two different scenarios, one being synthetic and one being conventional, it doesn't take a genius to see what they will use to slow down warranty claims.

I also don't think many folks know that Currie actually built a gear dyno and used it for a bunch of things. One was to define the oil path onto the pinion bearings in the high pinion 3rds set up in fabricated and Ford housings. They had some clear plastic over areas so they could spin the gears both directions and watch how the oil got slung around. Same kind of stuff Banks did but well over 20 years ago.

Currie at that time had absolutely nothing against synthetics and said as soon as they found some that worked, they would use it.

There is truth, lies and statistics.

What I find interesting is that most of the time that forum seems to be a decent resource in all things lubricant except in this case. And they question why many companies are at the minimum recommending Dino juice or saying that not running it will void your warranty not just Currie. Eaton Traction, Auburn Gear (hell they extend your warranty by an extra year if you buy their Dino juice and LSD additive), East Coast Gear, Dutchman, Dynatrac just to name a few. Really what they miss is if there was nothing to it these companies would not spend the time or resources to make the recommendations.

 

[MikeE024]

Isn't there a saying about trying to prove a negative? Just because someone won't share data does not make the conclusion of that data inaccurate.

FTX's internal accounting audits agree with this message lol.

Kidding aside, I agree with your message. A decision to keep data internal does not necessarily determine its validity, nor does its validity necessarily determine if it should stay internal.

There's another saying out there about making assumptions.

 

[MikekiM]

When I had my gears done on a previous TJ I had Revolution gears installed and followed their procedures.

https://www.revolutiongear.com/ring_and_pinion_break_procedure

I did 4.56's earlier this year and followed the Revolution Gear break-in as well.

Side note...I did the reggae and TrueTrac limited slip as well and quite possibly the best mod I've done to my TJ.

 

[Jerry Bransford]

There is truth, lies and statistics.

What I find interesting is that most of the time that forum seems to be a decent resource in all things lubricant except in this case. And they question why many companies are at the minimum recommending Dino juice or saying that not running it will void your warranty not just Currie. Eaton Traction, Auburn Gear (hell they extend your warranty by an extra year if you buy their Dino juice and LSD additive), East Coast Gear, Dutchman, Dynatrac just to name a few. Really what they miss is if there was nothing to it these companies would not spend the time or resources to make the recommendations.

I think some people simply like to argue.

 

[mrblaine]

I think some people simply like to argue.

I don't think that is even remotely accurate.

 

[MikeE024]

I did 4.56's earlier this year and followed the Revolution Gear break-in as well.

Side note...I did the reggae and TrueTrac limited slip as well and quite possibly the best mod I've done to my TJ.

I had my 5.38 Revolution gears REM isotropic surface finished and still chose to follow a normal break-in even though it may not have been necessary.

With manual hubs up front I figured the REM finish made sense for the front gears since there isn’t as much load driving around in 2hi with the hubs engaged, relatively little to no load when disengaged, and a bunch of load when engaged in 4low with the lockers engaged.

I changed the front and rear fluid after 500 miles of driving around town with the fronts engaged, disengaged the front hubs and then changed the rear fluid again sometime later (all using conventional).

No negative issues to report at this time, but I was surprised at how many small particles there were in my rear diff oil on the first change. I was expecting little to no particles. Based on seeing that, I recommend folks to definitely change the oil per the break-in instructions even if they opt for the REM ISF. The second fluid change in the rear looked very clean.