1960 B75 Mack

[Wes J]

Interesting question. All the trucks I worked on used 75W-90 or 75W-140 in the axles and straight 50W in the transmission. But, I don't get out much.

I've worked on a lot of old machines though. Some give an SSU rating. I've found that almost any modern oil will satisfy the minimum SSU spec'd in these old machines (more than 40 years old). Many old machines used straight 30W in gear boxes and spindles. There are much better oils available today. I often switch to something like Mobilgear 630 or even DTE medium.

 

[DMiller]

Was the standard for literally decades as to 40 or 50w in Spicer, 80/90 mineral in most Fuller and Eaton products, 85/140 third members or 80/120 for a select few. These days I know of so many variables due to my own machines and looking thru a few spec manuals, just could not imagine a Fuller running 50wt but they are.
Old Jeeps, a few Chrysler gearboxes and a very few old HD trucks with single countershaft gearboxes used the Whale Booger as we called it. Nothing else would hold up or lubricate well enough, I do believe the Chrysler dealers still sell that specific oil for the Jeeps as no one else offers or engineered a replacement.

 

[Truck Shop]

Eaton/Fuller has been 50wt motor oil since mid 70's, damn near everything these day's run 50wt synthetic. Eaton went to 50wt in their twin counter shaft boxes early on
because on a grade the 80/90 would fling out between the front gear sets and cause galling of the limiting washers especially if the clearance was set too tight.
When Eaton went to pressure lube on the front gear set and output auxiliary drive gear plus machining the main shaft with the clearance built in 50wt synthetic is the only
way to go. Hold the clutch down in real cold weather on start up with 80/90.

All rear drives have switched to 75/90 synthetic, but you don't want to use 75/90 in anything with brass parts it will deteriorate the brass same with the 50wt synthetic.
The oil companies don't tell you that on a container and most oil distributors don't even know that but call the service line at the oil producer and they will tell you it's
not a good idea to use it in old drive train with brass parts. I called Shell and it was verified.

We use 75/90 in wheel ends and the new Detroit DT series auto-shift transmission uses 75/90 for lube

Fact is transmissions and rear drives just last way longer with synthetic oil and run much quieter too.

Truck Shop

 

[DMiller]

Thanks TS Guess I am just old and too old school.

 

[Truck Shop]

Thanks TS Guess I am just old and too old school.

Your no more old school that me, I have been called a dinosaur more than once.

Truck Shop

 

[Truck Shop]

Scored some free parts today, three 1710 yokes for the SQHD drives and a 1710 intermediate drive shaft all parts in very good condition. Allen Chase of Hagerman truck parts/
salvage just up and gave them to me. It probably has something to do with the fact he has a AC Mack, Kenworth and old Pete collection plus a museum of old logging equipment,
construction equipment and some tractors. Thanks Allen.

Truck Shop

 

[DMiller]

DAMN!!

 

[RZucker]

Eaton/Fuller has been 50wt motor oil since mid 70's, damn near everything these day's run 50wt synthetic. Eaton went to 50wt in their twin counter shaft boxes early on
because on a grade the 80/90 would fling out between the front gear sets and cause galling of the limiting washers especially if the clearance was set too tight.
When Eaton went to pressure lube on the front gear set and output auxiliary drive gear plus machining the main shaft with the clearance built in 50wt synthetic is the only
way to go. Hold the clutch down in real cold weather on start up with 80/90.

All rear drives have switched to 75/90 synthetic, but you don't want to use 75/90 in anything with brass parts it will deteriorate the brass same with the 50wt synthetic.
The oil companies don't tell you that on a container and most oil distributors don't even know that but call the service line at the oil producer and they will tell you it's
not a good idea to use it in old drive train with brass parts. I called Shell and it was verified.

We use 75/90 in wheel ends and the new Detroit DT series auto-shift transmission uses 75/90 for lube

Fact is transmissions and rear drives just last way longer with synthetic oil and run much quieter too.

Truck Shop

Another bonus with synthetics, is that you don't stink of sulphur for 3 days after working on a gear box that used old conventional gear lube.

 

[Truck Shop]

Back to B75
I have reached a point where most of the big items are done. Radiator, engine, gear box and rear drives completed. My next point of work will be rear axle housings/suspension and brakes.
Then ready the steer axle I picked up on the cheap. FF 931 no front brakes. After those Items are finished I will order two new 29' X 10" X 5/16" frame rails from H-W Metals in Portland Ore.
The frame will be the a major job but also the easiest.

Truck Shop

 

[Junkyard]

Another bonus with synthetics, is that you don't stink of sulphur for 3 days after working on a gear box that used old conventional gear lube.

Even as girly as my daughter is she knows the various smells....diesel fuel, fumes, gear oil and the like. Laundry day she always makes sure her clothes don’t get tossed in with mine !

 

[Truck Shop]

Oh you smelly guy you! lol

Truck Shop

 

[Junkyard]

Oh you smelly guy you! lol

Truck Shop

If you only knew! Haha

 

[RZucker]

Back to B75
I have reached a point where most of the big items are done. Radiator, engine, gear box and rear drives completed. My next point of work will be rear axle housings/suspension and brakes.
Then ready the steer axle I picked up on the cheap. FF 931 no front brakes. After those Items are finished I will order two new 29' X 10" X 5/16" frame rails from H-W Metals in Portland Ore.
The frame will be the a major job but also the easiest.

Truck Shop

I might try to get down that way in the next couple of weeks, Harvest is getting over up here and I should get some slow time soon. I'll be letting you know.

 

[DMiller]

Can remember pulling 'Clean' work clothes out of a set fresh from laundry, still smelled of gear lube after a week of nothing but drivetrain work. Hard to get rid of that odor.

What crossmembers gonna use, Frt lnr? or bulldog? Going to reuse the front frame horns off the Mack for the front sheet metal/radiator support?

 

[Truck Shop]

That sound's good RZ, by that time I should be done with the axle housings. Started on those today-the rear drive hosing is stripped and the front won't take long to remove
and strip. Lucky the drums are in pretty good shape because there odd ball in-boards, high dollar to replace. Do have to replace some bad wheel studs but that was expected.

Truck Shop

 

[Truck Shop]

One of the hardest things to find so far is some wheel studs. The left hand studs are toast couldn't find any of that type left hand anywhere in the northwest.
Ended up finding what I needed from Van Horn Truck Parts in Michigan. A good Meritor-Euclid-BWP-NWRA and Conmet number but none around here.
R006023 R/L. Way it goes working on old stuff.

Truck Shop

 

[DMiller]

Found this link for Bulldog numbers, seems that old 75 was in a very limited run. I have a BIG soft spot for the L(T,J,M) series Macks and they are fewer still. Goes to a download pdf

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&ved=2ahUKEwjEy8u4r4PeAhVhxoMKHQBCAHEQFjAJegQIAhAC&url=https://www.macktrucks.com/-/media/files/museum/model-production-numbers-1905-2000.pdf?la=en&hash=420950B1E419064F74D7579DC492EF7241F9C63E&usg=AOvVaw2oi62QU7g2PPz4UlkuZb6Q

 

[DMiller]

Interesting on the studs, should have been a really common Old style cannot imagine inventories are that low but have been wrong before.

 

[Tenwheeler]

One of the hardest things to find so far is some wheel studs. The left hand studs are toast couldn't find any of that type left hand anywhere in the northwest.
Ended up finding what I needed from Van Horn Truck Parts in Michigan. A good Meritor-Euclid-BWP-NWRA and Conmet number but none around here.
R006023 R/L. Way it goes working on old stuff.

Truck Shop

Thanks for sharing with pictures! It is really looking good!

 

[Tenwheeler]

Interesting on the studs, should have been a really common Old style cannot imagine inventories are that low but have been wrong before.

That is because nobody keeps anything anymore. If X amount is not sold in six months it is not restocked. If it has been on the shelf a year or two through it in the dumpster and wright it off inventory for corporate. If they still have it they cannot find it. That is because the smaller companies are being sucked up. The people with much experience are being pushed out. They can hire three newbees for the same money. Our problem with that is all three of them put together do not know a third as much as who they replaced.
There are some good young people out there but dealing with the big corporations can be a reason for early retirement.