David

John, My truck has 65K rears and a triple frame with no rust. I believe it has spent most if not all it's life in the south. It was owned by Mayfield in Atlanta when that company was purchased by Guy Turner (aka Turner Transfer) in Greensboro. Some place along the line the Cummins was removed and a 12v71 and 6 sp auto from an off road rear dump was shoehorned in. We are installing a Big Cam 855 and Mack trans with a Spicer aux. It will be very close to original.

http://www.macktrucks.com/assets/mack/ModelProduction1.rtf John, This list from the Mack website shows 25 units built for the DM865. Mine is 1002. If this one is 1033, then they must have skipped a couple of numbers?

Rob, Very helpful. Thanks

714 pounds

Mack has shown two different shift patterns through the years for the 2090. The early one you didn't use L in high range. The later one you don't use 5 in low range. All of ours seem to whine quite loud in 5 low so we use the later pattern. The 9 speed was speced as an on/off road trans. The 10 speed was speced as an on road trans. Revs/mile X final drive ratio will give you RPM's at 60 MPH. 24.5's are 468 rev's/mile. 468 X (.71 X 7.49)= 2489 RPM's @ 60MPH. You might want to look at the T2050, 60, 70, or 80. They are .6 overdrive. Or use the 2090 and add an auxiliary with overdrive. 1200X24 tires will cut your Revs/mile down to 428. Play with the numbers and see what combination fits your needs.

They look like reading glasses!

It's only 26,000 pounds and not like there's any hills in the background!

You need to get out more often. There are all kinds of them around here. Check out this thread.... http://heavyequipmentforums.com/Forum/showthread.php?t=10932

This may be a really stupid question but I'll ask it anyway. I thought the inner and outer cam and the peanuts were part of the power divider. Why does a single axle truck have a power divider? I have an axle out of a RM 4x4 but the build sheet says it's a 5.78. I will check it Monday for a tag.

Should take off easy but on the other end it will need 2000 rpm for 60 mph (with 1100R22.5).

Here's one..... http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=130364897089&viewitem=&sspagename=STRK%3AMEWAX%3AIT

No. I've heard them called flat cams or z cams. Wedge brakes have a wedge (instead of the cam) located between the shoes.

Had a tractor with wedge brakes once. Just had to be sure it had a trailer behind it with good enough brakes to stop the whole rig!

Never seen one quite like this.... http://www.texasfiretrucks.com/1979mack.html

I have a PC40-7 that's been a great machine. It's paid for itself about a dozen times.

Here ya go... http://maine.craigslist.org/boa/1563132594.html

Wish I was on the west coast for this one.... http://cgi.ebay.com/ebaymotors/1985-Mack-Magnum-end-Dump-Truck-Reliance-Trailer_W0QQitemZ200433161782QQcmdZViewItemQQptZCommercial_Trucks?hash=item2eaabf5636

So, when you have the cab off, change the trans.

It would be much easier to install the B model cab and hood on the deuce and a half.

The output is turning 167% faster than the input (.6 x 1.67 = 1.002). If it was 40% faster it would be a .71 overdrive (.71 x 1.4 = .994). If it was a .5 overdrive it wouldn't be 50%. The output is turning 1 rev for .5 on the input. That's 100% faster or a 200% overdrive (the output is turning twice as fast as the input).

The trucks I've had with T2050 and T2060's have had 5.73 rears. These trans have a .6 overdrive which is not 40%. .6 input yields 1.00 output. 1.00 input yields 1.67 output, or a 67% gain. These are very fast transmissions.

1 DOWN 59 TO GO!

Started using them sometime in the '80's. I wonder if it would show up in an oil analysis?

Try rotating your outside wheels (one at a time) 180 degrees. It will put both valve stems in the same hole but you can see if it make a difference in shifting an out if balance problem.

120,000 miles is just about time for your plastic timing gears to go. After you get that fixed you'll spin a bearing because it will be plugged up with the plastic from the timing gears. Didn't mean ruin your day.