Pinion setting tool for mack rears.

[Markie Man]

Looking to purchase the Kent Moore tooling for setting pinion depth in mack rears and other mack specific tools. I am also looking for a dial indicator timing tool for the 855/n14 Cummins. 

Glendon (717) 543 1736

Thank You!

[Joey Mack]

Pinion depth is done with a dial indicator for back lash, and a vernier caliper to check shim thickness. and you need a 20 ton press to pre-load the bearing, and a small 'fish scale' and a piece of string to check bearing pre load..   and some Prussian blue on the gear teeth to observe tooth pattern in the 'root'.  we also need to know what rearend you have.. I assume a dual reduction Mack, probably a 92/93 series??  More info please..  jojo

[mechohaulic]

4 hours ago, Joey Mack said:

Pinion depth is done with a dial indicator for back lash, and a vernier caliper to check shim thickness. and you need a 20 ton press to pre-load the bearing, and a small 'fish scale' and a piece of string to check bearing pre load..   and some Prussian blue on the gear teeth to observe tooth pattern in the 'root'.  we also need to know what rearend you have.. I assume a dual reduction Mack, probably a 92/93 series??  More info please..  jojo

when work was fun; now the old age brain cells are taxed.i remember using a red/yellow tube of white grease instead of the prussian blue and can't remember the name .

[Markie Man]

Joey, yes crd92/93, if they can be set without the "variable pinion setting gauge" that the service manual shows I'm all ears. It consists of a tube and plugs and several pins that would be installed in place of the crosshaft/spur gear and allows you to set pinion depth with a feeler gauge. But if I can do without I'd like to hear it. this is my first time digging into one of these, always just swapped them out but this one simply had 2 bad races in the top chamber and since everything else looks good I am going to attempt to put in new bearings. I have rebuilt transmissions before but first time on one of these.

[Joey Mack]

gosh,,,  I would like to help you,  but I dont have the time to write the book...   are you able to read the svc book and sum up your own approach. are you replacing the top gears, (Bevel pinion and Bevel gear)? they are always replaced as a pair..  and there should be a measurment scribed into the pinion..  you can take the measurement from the old pinion, and do the math to help get you close to the shim thickness needed.  basicaly subtract the smaller from the larger, and that will be the shim adjustment needed.  (in a perfect world) but it will get you close if not right on the money..  also the shim rings are expensive..  I have cut my own shims out of shim paper and added them to the existing shim ring, provided I had to decrease bearing pre-load..  I get my shim paper from my local rebuilder shop..  .002"/ .003"/ and .004"..  cuts easy with a scissor, just like in art class..   jojo    I have to go check the grill..  got chicken cookin...  

[Vladislav]

There are two ways to set the mesh. 1st is using that asked tool and fitting pinion to the size marked on the gear set. The tool (more correctly to say the main tool of a set) is something you put in place of the differential since the base you measure the distance is the imaginal axle of the differential spin. But you need a physical base and not an imaginable. So you need a kind of cylindrical boss you put into the diff bearing basements imitating the diff and measure (with a measure tool) from it. Than make math and choose the shim thickness. I made such the tools for Mercedes car differentials I rebuild for money but wnen I started using the method I found out the actual mesh I got setting by the marked distance was not perfect (or sometimes quite wrong). So there's the 2nd way setting the mesh by check-printing it (as mentioned above) and correcting actual positions of the gears changing the shim pack thickness. Any book describing process setting of a diff gear mesh no matter truck or a car tells which gear to move which way to obtain correct mesh print. This method is more correct that setting by the marked distance since you see the actual teeth contact area. Which is important not only for no noise but for correct stress distribution between the teeth. Worth to point out the job is time consuming patient process not a common mechanical work.

Vlad