Dana 70 rebuild.

[pepecat]

Nylock and Timkin

Hi, I replaced seals, Hub bearing and nylock nuts on my rear end recently and found it to be a doable job, even though it was my first time. luckily I have access to a press at the airport repair station I work at to be able to press out and in the bearing races for the hub. A couple of things I found after asking around at NAPA and a lot of other repuatable car parts chains is that Timkin bearings are only found at heavy dudty truck rear end stores, etc. only one in the Los Angeles area. then ironically I had to check at Auto Zone and found that they actually have TIMKIN while kragen and NAPA carry an aftermarket Mexico or US brand respectively. Auto Zone really surprised me on that one, they also have Timkin axle seals as well. I have one CR and one Timkin, we'll see which one gives out first. I got my Nylock Nut at Ford for 20 bucks. And yes they are listed under the 80's trucks and vans. Good luck to all on this. I used the preload of 140? FT. Lbs. (can't remember exact SPEC) but it sure was tight, backed off 30 deg. the Axle nuts to 90 Ft. lbs. Happy wrenchin

Nick

 

[1stgen4evr]

axle nut torque

It has been years since I torqued the nut on the hub bearings. I just go by feel. 140lbs and 30 degrees back may be a good number but I would be sure that the hub turned freely when I got through. Are those numbers from the manual? I didn't even think of the hubs when I started this thread but should have given that some consideration. It is after all, one of the first things an owner will need to do on the Dana. The newer setup allows brake service without removing the hub. That would be nice at least every other time. I found that there was a good deal of slack on my hubs the first time I did the brakes. Couldn't possibly have been from loading the snot out of my truck. That 70 designation is 7k lbs. I sledom load over 4500 lbs. Well maybe 10 when I am hooked to the goose neck. The bearings had eroded into the nuts on both sides. I first thought of replacing the nuts but after considering that new nuts would not have conformed to the bearings like the old ones, I elected to reuse them. That was about 275k miles ago. Must be ok. Be very sure of the bearing setup here. If one runs hot and locks up, you will very possibly loose an axle. More 3/4 and one ton trucks hit the dead line from a bad axle than from crashes. It is hard to justify a grand on our old first gens.



1stgen4evr

James

 

[pepecat]

Torque Specs

1stgenner, the torque specs I used on my axle are from the site here. I searched for every thing I possibly could and found a post where someone had retyped or pasted the specs from the maintenence manual. There are other posts that quote this as well. I torqued them to the specified 140 Ft lbs and back it it off by feel basically. But yeah I did it while spinning the hub. I've done the job 2 times now actually, both sides for the seals and feel confident about the work. Timkin are the same brand of bearings in our Gulfstreams, from G II's all the way up to the GV's, also a lot of other aircraft use them too. But I'm sure the markup for their parts is rediculous.

 

[dpuckett]

TTT.



3-1/2 years later, and while I sold the truck with the 4. 10s, I am going to do this in my newly acquired W350 IF the center section is usable- lots of chunks out of the ring gear, and the pinion teeth are about half gone. If the center isnt usable, I may do some axle swapping and put my Dana80 under the W rig. I plan to use a known good/ quiet R&P from my C&C axle. This should be ok, shouldnt it? There is no discernable wear between the gears, IIRC. Some local yay-hoo said putting used gears in another center will make them howl. New gears arent made for my center, so by that theory, they should howl, too, right?



Are Yukon gears any good? G/F's shop has put lots of them in, but mostly in Chevies and Fords, and nothing with the torque a hopped up Cummins can make.



One more question- what is the purpose of the crush sleeve? Does it need to be included in the initial set up? I dont have my FSM handy, and just wanted to throw the question out there while I thought of it.



Daniel

 

[MMiller]

Just swap the whole setup from one 70 to the other, if you are worried about it. It would likely setup easier anyways. I would not worry about putting a used r&p on a different carrier. I've set up several sets of dana gears, some used, some new, and have yet to have a noisy set.



The guts from the c&c(carrier, r&p) will all interchange.



Yukon gears are fine. Thats probably whats in the rear of my 93, and we all know what that has gone through. They have about 40,000 miles on them right now. I just changed the gear oil in it, checked backlash, and its still in spec.



Dana 70 does not have a crush sleeve. The crush sleeve is how some rear diffs get the correct preload(measured by rolling torque) on the pinion. Dana's use shims under between the front pinion bearing and the pinion shaft.



I just setup a dana 60 front and two dana 80 rears. The one dana 80 rear has been back in service on an F350. The other two are in a pulling truck, that will not move until the season starts. If anyone can afford to go pulling this summer.



I've found there is alot of misinformation on r&p setups. Either a guy knows how to set them up, usually hates doing it, but does a good job. Or a guy thinks he knows how to do it, and ends up with noisy, broken rear diffs. Its easy to setup a noisy r&p in a half ton chevy pickup, with a 350 and auto trans and have it live. A noisy r&p in a diesel truck that gets worked will likely die. My $. 02.



Are you going to use new bearings, or used setup? The FSM has different torque specs on used, and new bearings, preload wise. I would also setup used gears a little looser then new ones(backlash wise). New gears will wear in(break in) rapidly and backlash will open up. Used gears, setup correctly will for the most part be already mated, and will not change much.



Michael



Keep in mind, I'm the guy that had to try 4 times to get my getrag setup right. :-laf I've never had that problem on diffs though, wether it be farm tractor rears, or pickup truck rears.

 

[dpuckett]

Maybe we should meet in the middle:-laf- I have yet to have any complaints on my Getrag setups.



I'm getting new bearings/ races/ clutches. The bearings are borderline, IMO, and I'd like to only do it once. I had thought of just swapping the old set up with the open diff, but I do like my limited slip in the 250- so long as friction modifier gets put in there.



How do you know when you have the pinion torque set up right? Rolling torque? (and how is that done, exactly?) I know I may have to move the pinion in/out depending on contact patterns, but for the pinion bearings in the housing itself is what I'm asking about.



Thanks for the input.



DP

 

[MMiller]

Rolling torque is the amount of torque it takes to keep the pinion turning. I have a dial type inch pound torque wrench. You assemble the pinion into the housing and install the yoke and nut to torque spec(250 ft lbs?). Then you put the inch pound torque wrench and it will tell you how much torque it takes to keep the pinion turning. I think with new bearings the spec is 20-40 inch lbs. If its too tight, ie too much rolling torque, then you must pull it apart, and put another shim between the front bearing and the pinion, then put it all back together. This will space the two tapered bearings further apart, decreasing the preload, thusly decreasing the rolling torque.



I've not had to change pinion depth much on a dana. I usually start with the same thickness of shims that was in the housing. I then get the rolling torque on the pinion set right, then I work on backlash. When backlash is in spec(new gears I like them tight side of spec, used gears the mid to loose end of spec), then I check the pattern and go from there. 3. 55's and 4. 10s have proven to me to be the easiest to setup. I've put together some 5. 13s in a mud truck, and they proved to be much more tedious to set up.



Michael

 

[dpuckett]

See this thread. Something tells me the carrier was in there too tight.



DP

 

[Moab4x4]

I took the plunge and installed a detroit in my D70. After reading this post carefully and asking some ?? at the local 4x4 shop I just swapped the carrier with the Detroit carrier. I replaced the bearings and races, but reused the shims and R&P. I just put all the shims back where they were before. It was a bit snug going back in as I now had new bearings to seat. I used the "big hammer" insertion method as I had no case spreader.

I did all this with the rear axle sitting on saw horses at waist height. I would hate to do this the first time under the truck. No way! I also installed speedy sleeves on both axle spindles. Again, TDR instructions to the rescue.



Thanks for the encouragement on this thread for the amateur mechanics. It wasn't that bad.