I'm putting my 4-speed back together after replacing (thanks, Matt) 3d gear, the 3/4 slider, and the synchros for third and fourth. I haven't done anything with the differential except to lift the assembly out of the case, decide that it looks fine (and had been working just fine going into this exercise). Do I need to check the preload before I put the transmission back together? And what exactly is the procedure for doing so?
Re: Differential preload check
October 26 2008, 9:08 PM
<<< Do I need to check the preload before I put the transmission back together? And what exactly is the procedure for doing so? >>>
Anytime you take the transmission apart and put it back together you should check the diff preload. Most likely the preload will be pretty close but you never know unless you check.
<<< And what exactly is the procedure for doing so? >>>
The proceedure is in the factory service manual. However, I have my own that works great. Before assembling the case halfs unbolt and remove the diff carrier bearing support from the left case half. After removing the four bolts, use a brass drift and a hammer and drive the carrier off the case by tapping lighty with the hammer. Remove the bearing race shim from behind the bearing carrier. Now flip the case over and use the drift to drive the outter bearing race from the case half.
Remove the O ring from the diff carrier bearing support and clean it and the mating surface of the case thoroughly. Now bolt the case halves together torquing the case bolts to 18 lbs/ft. Then set the bearing race back into the case half and drive it onto the diff bearing with the drift. Use a flat blade screw driver or cold chisel in place of the drift to ensure the race is fully seated in the bearing (Tap lightly).
Next drop the bearing shim on top of the race and fit support (without the new O-ring) into the case. Ensure that the bearing support is fully seated. Now use a feeler gauge to measure the clearance between the back side of the support and the mating surface of the case. Clearance should be about .005 to .007 inches. More clearance than that will result in too much preload and fry the bearings. To little clearance and the diff will miss align and wear the bearings and pinion gear.
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