Rebuilding a 3.07 Diff.

[Greenleaf]

Guys,



I have been reading the "How To Tips" and find it informative. Thanks James Oo.



One question... ... .



The FSM has PICTURES and it SHOWS checking backlash as side to side movement in the carrier bearings Figure #54 page 3-47 WHAT THE HECK!!!! Backlash is gear to gear contact. So Don't I want PRELOAD on the carrier bearings and . 005-. 008 inch gear to gear BACKLASH??????????????????????????



FSM stinks like a pig lot





GL

 

[B.G. Smith]

The explanation is confusing, what they are actually doing is determining the correct shim thickness to get the recomended backlash. They determined the shim thickness to get proper preload on the carrier bearings first but not how much shim on each side to get proper backlash. And yes, you're right. Clear as mud so far???? bg

 

[Greenleaf]

One more thing.



It was mentioned that the bearings are tough to remove. I was shown my my former boss who operated an OTR truck business to cut the bearing cage off with a cutting wheel. Let the rollers drop into a conatiner. Weld along the OD of the race and the race will then loosen it's grip and come off very easily. Works for removal of races from I. D. race bore and O. D. race hub. With the hub style, such as our carrier, you pop the race off hot. When removal of a race from the I. D. of a bore, you allow it to cool and contract.



This may be wrong but it has worked for me over the years.



Scott

 

[1stgen4evr]

Dana 70

Anyone that looks back at all the info that the guys provided, will be impressed with the collective knowlege of the group.



If you have not gotten the procedure, FIRST you have to get the carrier bearings set as to preload, THEN you must swap shims from one side to the other to accomplish the gear to gear backlash. Therein is the pita that the Dana is. It is very useful if you do much of this work to have a set of dummy bearings that will slide on and off so that you can do the shiming without ruining the new bearings. This is the reason for the special puller that is mentioned which will allow you to pull the bearing without damage to the cage or rollers. Also, I would point out that every time that you pull a bearing off or reinstall it, you abraid/swage the carrier hub and this can lead to less than desired fit between the bearing hub and inner race with the result that the bearing will begin to turn on the hub and this will lead to failure of the carrier. Of course, left uncorrected, the result will be loss of the gear set as well. I almost had this to happen on a 70 just recently and it was 'factory' and had never been repaired. The bearing on the gear side of the carrier really needs to be an inch bigger as it takes more load than the other side. I would add that this happened at 470k miles. So it has done pretty good after all. I had a spare carrier and was back running in just a few hours.



The welding on outer races is well know to me. I have not had as good success with welding the inner race. I have used a cobbled up puller that I made with a short piece of pipe and forcing screw to pull the inner race. Also, I very often reuse bearings and only weld one that is already visably spoiled.



Hope you got your going.



James



There is another question running now regarding a loan around puller. To my knowlege, no such thing is available. It would be expensive to ship around and I don't know who would spring for the initial outlay. What I have been trying to figure out is how one might make a simple puller that would work which was not so expensive to build, then, anyone who wanted to do their Dana work could be assured of getting it right. Any input from the creative cobblers on TDR????

 

[Greenleaf]

I purchased a set of bearings to use as "set up" They worked very well. The cost is minimal when compared to the service tool set.



GL

 

[1stgen4evr]

set up bearings

GL, how did you open the bore on the extra set so as to have a slide fit? I had my uncle open a set with a SUNNEN honing machine. I had him do the big bearing on the pinion shaft as well.



A set of dummy bearings would be something that could be shipped around for members to use, however the freight would be about as much as having a set done.



James

 

[MMiller]

James,

I just take a 'flap wheel' on my die grinder and polish the inner surface of the bearing until it is open enough to slide on and off the carrier.



Scott

I set up mine so I have to beat the carrier in to the housing with a soft hammer and pry it out with a prybar. Any more preload and I cannot remove/install in my garage as I don't have the tooling to spread the case. My rear diff probably has 15,000 miles on it since the I did the r&p. Thats mostly heavy towing, and all heavy fueling. After I get the preload tight as possible in the diff housing then I start switching the shims around until the backlash is in spec, I usually go for the tight end of spec and make sure the pattern is good. Then when everything is honeky dorey then the new bearings go on. The last two times however I have had to take the carrier in to a drive train shop and have them pull the bearings and switch out one thin shim, as my set up bearings are evedently a little differnt then the new ones. The last diff I did was my dana 70 rear 3. 55. The one before that was my brothers dana 60 front with 5. 13's. That one was tough with the small pinion. The smaller the pinion the more crucial gear contact is. Your 3. 07 is going to be quite forgiving.



Good luck-let us know if you need more help. I've got some pump questions for ya Scotty!



Michael

 

[Greenleaf]

I have new "set-up" bearings so there should be very little difference between these and the final install bearing set.



I used a die grinder with a sanding wheel attatchment to open the bearing.



The carrier bearings are set tight enough, that I too have to beat the carrier into the housing and use a prybar to get in and under it for removal.



Scott

 

[1stgen4evr]

gear contact

"Your 3. 07 is going to be quite forgiving. "



There was no clearly identifying noises comming from my 3. 54 as the bearing (on the gear side) was comming apart. There was noise but I had previously had some problems with the Getrag and was fooled into thinking I still had a problem there.



Obviously, the 3. 54 is somewhat forgiving as to contact. Reassembled with a different carrier, there is still no noise even though the wear pattern can not be the same as it was.



I did a 9 1/4 chrysler rear end last year and had significant problems with noise in a van application even though I had a good pattern of contact. I used the gear set that my nephew provided and later found that the van application requires a special set of gears. We got some improvment with a larger backlash.



These experiences lead me to think that too tight on the gear contact is more of a problem than too loose (to a point).



Lots of these truck are getting to the mileage that will require attention to the Dana. To anyone that is thinking about doing their own, it is doable with proper attention to detail. As I pointed out the the earlier discussions, these parts are quite heavy and will pinch the @#$%^& out of your fingers. Use caution handling the carrier in and out. I have done this job under the truck and on a stand and I like the stand much better. It adds some considerable time to the job if you pull the entire axle from the truck.



I agree that a rubber hammer will take the place of the spreader but I have used both methods and prefer the spreader. You CAN get the preload too tight with the spreader. Going back with old bearings, I only set the preload such that light bumps with the soft hammer get the job done.



James

 

[MMiller]

James, I was just making a blanket statement. A ring and pinion set with a large pinion gear diameter(ie higher gears) will be easier to set up becuase of so much material on the pinion. When you get into the 4. 56's-4. 88's-5. 13's the pinion gets very small diameter with much less tooth contact. These are more tedious to set up correctly.



I have not fought a noisy gear set yet, dunno if its luck or my hearing isn't very good



Michael

 

[1stgen4evr]

Michael

Oh I knew. I was just adding my experience. I was mostly considering those who will be needing to do theirs in the near future. Sort of pushing them to the plus side. I expect there are mostly 3. 54 users and wanted to add my situation to what was already said.



I know my hearing isn't what it used to be. That is the reason I use the cup on the shift stick to amplify the drive train noises. I still fool myself with following something that was 'wrong last time'.



Anyone who doesn't know, Michael is a professional mechanic. He would also be a hobby mechanic from the pictures he sends of the make or break it treaking with his fwd Dodge. You can go to the bank with his advise.



James

 

[MMiller]

Now James, don't be telling these guys everything about me. I don't know all, I guess you could call me a Jack of all trades and master at none! :-laf I've seen a little of everything, and turn wrenches for a living, broke about everything in a 4wd dodge, and still can't get the carb tuned in on my 440 for nothing. Went out trcuk pulling this weekend, got third and broke the rear ujoint and drive shaft. Guess its to the drive train shop for a stronger setup!



Now that we have this thread all jacked up, I'll bring it back to topic. I think we have Scott straightened out, however I think he had it handled, just needed a little assurance. Anybody else reading, don't be scared of them dana axels. Ring and pinions are a lot of work and measuring, but not impossible for most weekend mechanics. If you would have no problem overhauling an engine, then a diff is doable. Just measure, and remeasure and look it all over again.



Michael