Dana 35 setup

[MAranger]

Hi all,
newer member, looking for help with my front end project. I bought front and rear axles, 3.73's, to replace my 3.07's. The rear pig was mint. The front I wasn't so lucky. All the bearings were rusty, all seals dry and cracked. I have all new parts for the front diff, minus the gears and carrier themselves. I am at the point of being ready to bolt it all together, all races are in place, etc. I have observed that neither diff (original or my swap) had shims under the caps, are they required? Also, is the outer pinion bearing (closest to driveshaft) supposed to be a slip on fit, or a press fit? My new bearing wants to be press fit. I have read a few different write-ups on diff overhauls, they all differ. How worried do I need to be about tolerances/figures such as pinion depth, pinion bearing preload, backlash, etc? I am looking to set the diff up myself, as I'm a broke college kid. My diff will only be used used low speed, wheeling or snow, so I am willing to settle with good enough as long as the thing will hold together. One more question, neither of my diffs had a retaining bolt in the spider cross shaft, did both lose theirs somewhere along the way, or is one not required?
Any help will be appreciated.

Thanks,
Erik

 

[Shran]

Have you ever set up gears before? If you haven't, I would suggest having someone do it for you and let you watch if you want to know how to do it. It's critical to get it perfect or it will self destruct very quickly even if it's only used at low speeds. Usually this only costs $75-100 and it's worth it for having it done right.

Both cross pins should have bolts holding them in...but the heads are known to break off.

 

[metalmacguyver]

Both cross pins should have bolts holding them in...but the heads are known to break off.

The front D35 pig uses a roll pin to retain the cross pin.

 

[4x4junkie]

Since you're retaining the original gears and carrier, I would say it might be worthwhile to try it on your own (the pinion depth and backlash shouldn't change too dramatically with simple bearing replacement), but you will need a few special tools though, and you'll want to check the gear mesh pattern when you're done anyway.
With the new bearings you'll need a new crush sleeve and to reestablish the pinion bearing preload (a beam-type inch-lb torque wrench is needed for that). A bearing puller and a press will make R&R'ing the bearings much easier as well. Also, a case spreader (can be home-made easily) makes getting the diff back in the housing much easier (be careful you don't spread it too far and damage it though, just enough to let the diff slip in & out).

There should be shims on the outside of both carrier bearings in the housing. The OEM ones are usually single shims, a little under 1/8" thick. Be sure you don't mix these up or you'll have problems.

As for the outer pinion bearing, mine was a loose press-fit... tight enough you can't just put it on by hand, but loose enough light-medium tapping with a hammer & punch could still move it on the shaft. The pressure against the crush sleeve keeps it's race from spinning on the pinion shaft.

 

[MAranger]

I have the shims that go alongside the carrier bearings, no problem there. I have already replaced all races, and have the carrier bearings pressed on. I have the new crush sleeve for the pinion shaft that just slips on. If I give it a shot at putting it together, the procedure I might follow would be (please correct me): insert pinion shaft with inner gear and crush sleeve on it, place and drive on outer pinion bearing until the pinion is snug, put on yoke and start nut (with or without seal under it?), put in carrier w/shims alongside the bearings, tighten caps marginally, fix the carrier to hold the pinion in place (or should it be spun torqued?) and torque the yoke nut to pinion preload spec (in/lb#???,ft/lb#???), use grease or some marking compound to check gear mesh, and pray they are sitting nice on each other. If they are, final torque everything, if not then i'll bring it to somebody. If it's not spot on and needs to be setup again, will I need to replace the carrier bearings to get it right?? my buddy told me this, I'm not sure. My ring will pop in and out of the housing without hitting, so no case spreader.

I appreciate your speedy replies. I just want 4by back so damn bad and winter is coming soon. Here's one for you guys

Thanks much,
Erik

 

[4x4junkie]

Not good, the carrier MUST be snug in the housing (the reason for the spreader, or at least a big rawhide (or similar) mallet to beat it back in).
If it's not tight, then it will need to be reset up again (sorry for the bad news).

Adjustment of the gear mesh and bearing preload is through use of different thickness shims. Bearings are all more or less the same.

 

[MAranger]

yes, the carrier has resistance slipping into the races. I misunderstood what the spreader does, I thought they were used to clear the housing of the ring gear, I didn't think about how it would stretch the races. I'll try a soft mallet, if all else fails, I'll make a spreader.

Any notes on the procedure?

thanks, Erik

 

[4x4junkie]

If it still has significant resistance in the housing, you're probably good then.
Yeah, the spreader spreads the case so the bearing races can slide in easier.

FWIW, here's the one I made:
(click for big)



Whatever you do though, never spread the case more than 0.015". Spread it JUST enough that the carrier will slip in with a slight drag at the races. After the spreader is released, the diff should then have enough resistance that it would otherwise take a prybar to dislodge it from the housing.

Hope that helps. Good luck on it.