New Gears..... Update!

I agree with you, GMW. I've been absolutely pleased with this truck and have no plans of getting rid of it. Guys can't understand why we keep these things on the road. I can't understand why someone would trade up for a few years newer with absolutely no idea of how the vehicle was maintained and what problems could be looming.

I just spoke with Gears Unlimited and they used Lucas 75-140 gear oil. HIs explanation was that many of the rear differential manufacturers are now recommending good old fashioned mineral oil for your gears and claims that there are some noise problems associated with running synthetics in rear ends.

A visit to the Eaton site confirms this:
Q: What kind of oil should I use? Can I use synthetic? Do I need friction additive/modifier?

A: A quality petroleum/mineral based oil works best in the Detroit Locker units. We do not recommend synthetic oil. Friction additive/modifier is not required.

Also, from Popular Mechanics:
Synthetic oil is a confusing topic, and there's a lot of rhetoric, largely because some manufacturers and peddlers of synthetics have made a lot of inaccurate and self-serving claims over the years.

I have no doubt that the synthetic oils have their place in our vehicles but not in every instance. If GM says to use synthetic oil in their rear differentials, it's likely that some synthetic oil manufacturer is paying them to recommend it. It's about the $$$ and it happens in every industry. If people don't think this happens, just watch TV and count the number of Physician Recommended products that are advertised daily.

gmw photos wrote:
OP, glad to hear you are happy with the outcome. And again I go back to one of my earlier posts in that it's good to see guys keeping an older, paid for truck on the road, and modding it if they feel the need, for current duty. There is a LOT to be said for a vehicle that we don't have to have a fortune tied up in, that can still do the job, and also make us really enjoy driving it. I feel the same about one of my trucks, a 11 year old vehicle that I love driving every day.

I'm still curious what exactly the gear oil is they installed in your diff. If you know the brand, weight and type, that would be interesting info to share with us.

As a side note, I ran royal purple ( syn ) for a while in the Nissan diff, and sent a sample of it after about 25K miles to blackstone lab. The report was essentially identical to the report I also did earlier with Nissan branded diff oil ( no idea who makes the Nissan oil ). Royal Purple sure is costly !

To those who keep their vehicles a long time, having fluids analyzed at a lab is a fun exercise if you are a vehicle information junkie. I use blackstone-lab. It's fairly costly though if you do it often.

OP, glad to hear you are happy with the outcome. And again I go back to one of my earlier posts in that it's good to see guys keeping an older, paid for truck on the road, and modding it if they feel the need, for current duty. There is a LOT to be said for a vehicle that we don't have to have a fortune tied up in, that can still do the job, and also make us really enjoy driving it. I feel the same about one of my trucks, a 11 year old vehicle that I love driving every day.

I'm still curious what exactly the gear oil is they installed in your diff. If you know the brand, weight and type, that would be interesting info to share with us.

As a side note, I ran royal purple ( syn ) for a while in the Nissan diff, and sent a sample of it after about 25K miles to blackstone lab. The report was essentially identical to the report I also did earlier with Nissan branded diff oil ( no idea who makes the Nissan oil ). Royal Purple sure is costly !

To those who keep their vehicles a long time, having fluids analyzed at a lab is a fun exercise if you are a vehicle information junkie. I use blackstone-lab. It's fairly costly though if you do it often.

Guess I'm no longer driving a GMC Suburban K3500 anymore...ever since changed out the OEM steel wheels to Alcoa Forged Alloy's....or that did not buy new tires from GM but Michelin & now Bridgestone and they are NOT the OEM size...or that my fuel filter is not Delco...or that my air filter is not Delco...or that my radiator is an after market (can't remember the OEM of that thing)...or that my fan clutch is no longer Delco, but TRW...or that my automatic door lock motors are no longer Delco...etc, etc, etc, etc...

Oh for that matter...just about everyone out there who has replaced their components with non-OEM no longer drive the OEM vehicle that left the factory with....

And that you have tuned the computer...it is no longer OEM, so what does that say about your vehicle...

Yes, best toss the glove box manual and if you bought the shop manuals...toss them too...ditto for any Internet search for info...it no longer applies to 'your' vehicle 'cuz 'you' changed some components on it....

roadjunkie wrote:
Who warrants my new gears? GM or the gear manufacturer? I'm running what is required to maintain the warranty on the new gears.

HTElectrical wrote:
Not running synthetic gear oil goes against what the manufacturer recommends. The Purple Grape Juice is Full synthetic, and right from your owners manual GM recommends:

GM wrote:
Rear Axle
SAE 75W-90 Synthetic Axle
Lubricant (GM Part No. U.S.
12378261, in Canada 10953455)
meeting GM Specification 9986115.

Who warrants my new gears? GM or the gear manufacturer? I'm running what is required to maintain the warranty on the new gears.

HTElectrical wrote:
Not running synthetic gear oil goes against what the manufacturer recommends. The Purple Grape Juice is Full synthetic, and right from your owners manual GM recommends:

GM wrote:
Rear Axle
SAE 75W-90 Synthetic Axle
Lubricant (GM Part No. U.S.
12378261, in Canada 10953455)
meeting GM Specification 9986115.

https://my.gmc.com/content/dam/gmownercenter/gmna/dynamic/manuals/2005/gmc/sierra_1500/2005_gmc_sierra_owners.pdf

Not running synthetic gear oil goes against what the manufacturer recommends. The Purple Grape Juice is Full synthetic, and right from your owners manual GM recommends:

GM wrote:
Rear Axle
SAE 75W-90 Synthetic Axle
Lubricant (GM Part No. U.S.
12378261, in Canada 10953455)
meeting GM Specification 9986115.

A few things people have misconceptions about:

#1. Gears give you more power at the wheels.

They don't. In fact, the lower the gear (numerical higher) the LESS power they put to the wheels. They just give you more torque at the wheels but less power. If gears gave you more power you would see 18 wheelers flying up the mountains around here. Instead they crawl up the hills at 20 to 30 MPH, sometimes less.Learn about power explained.

#2. Torque and power are the same.

They are not. Power is time based. Torque is not. Torque is just a twisting effect with no time penalty. Power is how much twisting effect you have and how fast that twisting effect is applied.

#3. Gasoline tuners give you a bunch more power.

They don't. Unless you think 10 to 15 HP is a bunch. The only way to make a bunch more power with a gasoline engine is with a bunch more air flow and tuners don't/can't do that. Sure, you can pick up a handful of power (15 HP) like the OP did by playing with the engines timing. This is the reason supercharging an engine gives you a bunch more power. With gasoline: More air= more HP.

#4. Manufactures leave a bunch of power on the table.

They don't. Well not really. They leave it on the table, but for a reason. An example of this is the Corvette with a 700R4 transmission. When the Vett came out with the 700R4 tranny way back when, the tranny wouldn't live under full power shifts. So GM got tricky and pulled timing (and power) so the tranny would live. This is just one example of a long time ago. There are bunches now days and more all the time. Another example is fuel mileage. Manufactures can get better fuel mileage. The problem is NOX would go sky high. It takes fuel (energy) to run the cat converter. If we didn't care about NOX getting out of hand we could have vehicles that get better mileage. We do, so we don't.

I learned a lot about perception of performance when I used to run my Mustang out at the drag strip with some friends that also had performance vehicles.
My conclusion is that perception is often deceiving. However I am sure that the new gears and tune together have made a real difference in drivability.
I would recommend same mods to anyone else any day of the week.

It all makess a difference, but the diff ratio does the most or has the most impact...all other things equal


Just look at any OEM MTWR (tow rating) or GCWR (gross combined weight rating) chart

Note that these are all 'stock' vehicles and 'stock' engines. Within anyone of them...there are two or more MTWR or GCWR and the difference is in diff gear ratios




GM....as the OP has a GM/GMC pickup...and as always...note the fine print qualifying those MTWR's that is on ALL OEM specifications. Also note that he went to 4.10's, which is off the charts so to speak...

GM TRAILERING AND TOWING CHARTS








For the Ford folks
Ford F150 2016 Pickup






For the RAM folks and chose the 3500 to show that this is NOT just a half ton thing, but any sized rated truck...even cars, but there are no charts for towing that I could find
RAM 2017 3500 towing

Hey! If you're happy with it, then it's worth every penny! I'm still standing by the performance you feel is from the new gears. They'll make the truck feel half it's weight on take off and highway cruise. The tune is almost all in the re-ramped gain of the TPS. That will give the perception of more power as it IS giving more power for the same throttle position. I'm anxious to read your towing report! :B