742 case setup help

-
7dart0

7dart0

Well-Known Member
Joined
Apr 20, 2012
Messages
491
Reaction score
104
Location
peabody,ma
I have been trying to set this up myself. Right now I have the stock shim under the big bearing no shim on the small bearing just snugged the nut for some bearing preload for gear mesh purposes. I have about .007 backlash at 3 spots.

I attached some pics for the pattern. Is it acceptable?

The gears are brand new Richmond 4:10's. All new timken bearings.

20180827_124022.jpg


20180827_124014.jpg
 
I have a 742 that I have gone through twice.
The gear patterns look fine, but when I checked the gear mesh I had the pinion nut more than just ‘snugged’. I ran the torque up to 125 foot lbs, just to be sure the bearing were seated.
Are you using the same shim set up as the prior ring gear or have you worked you way into the current set up?
I don’t remember the back lash spec. So I don’t know if the .007 is good.
 
I snugged it so there was drag on the bearings, close to the 20 inch pound turning torque. The ring gear was marked from Richmond for .008 backlash and I got it .007.
 
7dart0 said:
I snugged it so there was drag on the bearings, close to the 20 inch pound turning torque. The ring gear was marked from Richmond for .008 backlash and I got it .007.
Click to expand...
IIRC the final torque on the pinion nut is around 240 ft lb,,
Your snug setting is no where near that. You will need to put some load on the pinion bearings to get an accurate pinion torque number and when determining the pinion torque to turn, you should have a torque wrench that reads in 1 lb increments.
 
Last edited:
I went by what a member here did with there 742 case. He had talked to cass (dr. Diff) and was told the 10 spline pinion should be torqued to 170 ft.lbs not the 240 that's in the service manual. Also should be between 15-25 in.lbs rotation torque without seal in and a couple more inch lbs with seal in.
 
For the torque wrench that you are using to measure the pinion rotation, what is the resolution of the measuring scale and what is the highest torque that the gauge will measure?
 
It measures 1 in lbs at a time. My rotational torque is 23 in. Lbs. It is calibrated through my lab at work along with my other gauges and measuring devices.
 
While turning the pinion nut, place a block of wood between the case and sure grip to get some drag on it, then check your pattern.
 
You must log in or register to reply here.
-

Back
Top