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Heavy Duty Trucking (HDT)  /  March 16, 2020

Mack Trucks introduced the Mack S852, an 85,000-lb. gross axle weight rating of its proprietary tandem drive axles, which is available for order now. Customers can spec it for specialized severe-duty or heavy-haul applications on Mack Granite models. For extreme loads at slow speeds, the S852 tandem drive axles have a creep rating of 105,000 lbs.

Today’s Mack drive axles are engineered with a double-reduction design and include several design advantages implemented through continuous research and development efforts, according to Mack, such as the use of Durapoid bevel and helical gears. This design provides favorable gear tooth geometry that helps eliminate localized stress and loading on the gear tooth end, providing enhanced strength and longer gear life. Frictional losses are also reduced in this gear design, allowing Mack axles to deliver up to 1.5% improved fuel efficiency.

“Low-traction situations can be a challenge for truck drivers, seriously impacting their productivity,” said Roy Horton, Mack Trucks director of product strategy. “To help address that issue, we offer standard inter-axle and optional inter-wheel power dividers that automatically distribute torque between the slipping and non-slipping axle or wheel respectively.”

The axles also feature a top-mounted carrier design that is not only less prone to main seal leaks, but also provides more than two inches of additional ground clearance. An additional benefit of Mack’s top-mounted carrier design is improved driveline angles between the drive axles. Instead of a three and a half to eight-degree angle, Mack’s prop shaft angle is just one to two degrees. This maximizes universal joint life, allows for greater axle articulation and reduces vibrations for a smoother ride. It also reduces torque losses for improved efficiency.

The new rating comes as Mack celebrates 120 years of drive axle design, engineering and manufacturing this year. “Mack has a long and rich history of engineering and manufacturing its own powertrain components, including drive axles, as it fits with our philosophy that components designed to work together, simply work better,” said Horton. “We welcome the new S852, which will broaden the applications our trucks are built to handle.”

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Now if only they offered this while they still made their manual transmissions, the North American Titan and still offered the MP10.

Then maybe they could have got back some of their Northern Ontario, and Quebec logging customers.

Here's one installation from Con-Expo. Not my pics. Were sent to me.

con1.jpg

con2.jpg

con3.jpg

con4.jpg

con5.jpg

  • Like 1

I kinda agree KS. While on this subject (I only have experience with low geared  planetary rears off road) but are there speed restrictions with planetaries? Can they be used at highway speeds to 55 MPH?

8 minutes ago, Bullheaded said:

I kinda agree KS. While on this subject (I only have experience with low geared  planetary rears off road) but are there speed restrictions with planetaries? Can they be used at highway speeds to 55 MPH?

They absolutely can !

All three of my Midliners were planetary hubs and I never had any problems with them. Smooth and quiet.

  • Like 1

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

Just now, Bullheaded said:

A Midliner?? I never saw one of those with a planetary rear?

Yup. CS-300P trucks. RVI drive axles.

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

3 minutes ago, Bullheaded said:

Do you have a pic Rob?

No, not of the axles. Don't believe I ever did photograph anything on those trucks as really never had any problems with them.

This was my personal one which I kept pretty much local unless another was in for service:

image.thumb.jpeg.2455f7d29058f7bd636c46cfcfd72990.jpeg

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

OK thanks. I would have never guessed that would be a planetary on that. Nice little truck. That would be handy as hell. I always wanted a rollback, but I had enough nightmares just trying to insure my F550 here in Ontario let alone a true medium duty. All the insurance companies told me "we can't insure it for personal use because it is a commercial vehicle, and we can't insure it commercial under your business because you are driving it for personal use." ????????????? LOL

1 minute ago, Bullheaded said:

OK thanks. I would have never guessed that would be a planetary on that. Nice little truck. That would be handy as hell. I always wanted a rollback, but I had enough nightmares just trying to insure my F550 here in Ontario let alone a true medium duty. All the insurance companies told me "we can't insure it for personal use because it is a commercial vehicle, and we can't insure it commercial under your business because you are driving it for personal use." ????????????? LOL

I hauled insurance salvage vehicles out of Chicago for years with two of the Midliners, a GMC 7500, and and two IH S1900, 4900, and S1700, 4700 series. Exited that business in 2005 when the industry collapsed and haven't looked back. Never had loans on equipment and sold everything clear and clean.

The Midliners were full air brake systems and besides the occasional air compressor problem, were trouble free. The rear axle housings were funny looking in those trucks and the cap had the planetary gears with the Sun being mouted to the drive axle shaft. Only ever seen photos and never actually had one broken open myself as didn't have leaks, or broken parts to deal with.  

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

That black one was a 1989. The white one was a 2000, and the blue one was a 1994, or 1995. All the axles were the same and the engines were 210hp with BDSL-181 six speed transmissions. In my memories of running them they were absolute "Gems" to own being very comfortable and smooth. They were however maintained very well during my tenure.

  • Like 1

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

I'll have to look for Polaroid photos of the blue one as it had a drop axle, 28' bed, and stinger to haul three cars. That scan of the black one is from a Polaroid photo originally too. Didn't get a digital camera till 2000.

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

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