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DIY Pinion Seal Replacement - Dana 80

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Alright, kinda wish I would have taken more pictures, but I was hot and ready to get it back on the road... So here is what I got, perhaps this will help someone looking to replace their own.

First things first. Go out and take a look at your Dana 80. Now, I don't have a photo of the other type for comparison, but there are actually two different Dana 80's in the 2001 and 2002 model year. This is important to get the proper seal. For my axle, in a 2001.5 Ram 3500 quad cab 2wd diesel 6 speed, it has the non flanged yoke and the double stepped down pinion shaft seal.

Part number is 5015618AB from Dodge...

Now the other seal (for the flanged yoke) is 5073944AA... Here is a picture of what a NON FLANGED YOKE looks like.

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So.. If yours looks like this, you must go with the top seal ending in AB...

Now for the required tools.....

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-Some kind of torque multiplier (Pinion nut is TIGHT)

-Various hand tools (sockets and driver to remove the driveshaft)

-Craftsman, 2 jaw puller, small one and the large one

-24" Pipe wrench or miller tool 6719 yoke holder. I am poor, so I used a pipe wrench.....

-1 7/8" craftsman 3/4" drive socket. Details later....

-torque wrench

Now, about the 1 7/8" socket... You can go try and find a thin wall socket of that size, or you can spend $25 bucks at sears for this socket and take some meat off it (yoke is thick inside around the nut for strength)

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Now how to do this.... First, the service manual says you need to check pinion bearing preload with an in-lb dial type torque wrench with the wheels and brake completely removed. I did not do this. Why? Because I used to work at a Dodge dealer and we NEVER had any problems doing it the way I did mine and am about to explain to you.

This axle does not use crush sleeves for bearing pre-load... It uses shims, like most H.D. rear ends. Now, the way I do this is the same way that the FORD service manual spells out the procedure for their trucks equipped with the dana 80.

Ok, so here is the problem...

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1. First thing you want to do is clean and dry up everything around the yoke as best you can.

2. Mark everything with a sharpie or paint pen to realign it later.

3. Block the front tires and support the rear of the truck with jack stands.- or do this on your lift. Also put tranny in neutral.

4. Remove the u-joint retaining hardware. The u-joint caps on mine were rusted into the yoke... Don't use a hammer to try and free it if yours is this way, you can damage the pinion bearings. Take a big pry bar and pry it apart. It will come.

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--Now you can see that beast of a nut. I sprayed some penetrating oil on the treads of the pinion shaft to make it easier to unscrew.

5. Take your pipe wrench or yoke holder and pin it against the frame or put a cheater pipe over the end and brace it against the ground. You are trying to secure the pinion and yoke from rotating as you try to remove the nut.

6. Hope you ate your wheaties, if you don't have a tq. multiplier you are going to have to get a 3/4 drive breakover bar and cheater to get this thing loose or a beast of an impact... I used a 1:6 torque multiplier that is 1/2" input and 3/4 out. It was tight.

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and once its loose, you can just start unscrewing it.

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7. Get your 2 jaw puller and go to town on that yoke.... MARK IT FIRST!!! It needs to go back on in the same position it came off!!! It is tight all the way off!!!!

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Inspect it... Probably will have a nice little groove... Mine did... If the groove is bad enough, it WILL ruin your seal quickly. You can get a SKF Speedi Sleeve for the yoke or buy a new yoke from dodge ($140)

8. Now you can pull the seal out. Mine was a bit** and I ended up just destroying it to get it out... :banghead:

Now you are almost to the finish line!!!!

9. Use a seal driver to install the seal. Make sure it is seated fully.

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10. Put the yoke back on. It is tight!! You will have to use a rubber mallet probably to get it seated far enough to thread the nut and washer to get it cinched down the rest of the way....

11. Tighten it up until the yoke is back in it's home completely.

12. Get your pipe wrench again and pin the yoke where it wont try and rotate. Torque the nut to around 450-500 lbs. Most will disagree on this step, there is some debate about on the correct torque for used bearings... I have seen them do it at most shops, they just impact it off and then back on... I don't trust that method... I set my torque wrench to 80lbs through a 1:6 multiplier and came out with something close to the factory tq. spec. NOTE: most say to use a new nut, but I did NOT. WE shall see if this bites me later on. I don't THINK it will loosen up from 500 ft lbs. That is pretty tight. But who knows....

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Could you list places to get some of these tools like the torque multiplier and pullers and such? :shrug:

You got it. :thumb1:

Snap on makes a great torque multiplier... BUT they are pricey!!!! The one I used came from Northerntool.com BUT it is an older one that has been discontinued... They do have another one that looks to be pretty good. About $179. Little expensive I know, but I have found it to be very useful on the farm on stuff like tractor lug nuts and dozer track bolts and such. LOVE it and you can disassemble it and grease all the planetary gears up real nice, should last forever if not overloaded!

The pullers, you can get them from sears.com. They sell a 2 pack of craftsman branded ones that are guaranteed forever which is always good! Or you can get them from Snap-on, mac, and similar... Make sure that it is has long teeth though! The seal on my dana 80 was HARD to pull because it was mostly rubber, have to really get a puller with long teeth to get in far enough to get to the metal part of the seal to pull it.

Torque wrench, just anywhere. I had a snap on but, it was stolen...... SO, because money is tight, I looked around a lot and found northerntool.com has some good prices as well as a lifetime warranty on theirs!! SO that is what I went with. Anybody have any other questions, feel free. :thumbup2:

--- Update to the previous post...

Also, you need to check the pinion bearings for play. With the driveshaft removed and before you pull the nut or yoke, see if you can move the yoke and pinion up and down. If you can, then you are going to have to look into replacing the pinion bearings. They can get bad over time when the fluid level in the rear axle is low...... But if you keep up with fluid changes and stay on top of leaks you should be good to go! My seal failed because it simply wore out after 10 years... ALSO, check your axle vent tube for obstruction as well as the vent orfice on top of the axle, stick a pick in it and wiggle it around. One reason a pinion seal can fail is a plugged diff vent...

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  • 7 months later...

Smokeythedodge,I have a 3500 2001 QC 4x4 dually and I am trying to determine the rear axle BOM #. My truck has the same rear seal as shown in your post. If your axle still has the BOM tag would you be willing to post the number?ThanksIan

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Smokeythedodge, I have a 3500 2001 QC 4x4 dually and I am trying to determine the rear axle BOM #. My truck has the same rear seal as shown in your post. If your axle still has the BOM tag would you be willing to post the number? Thanks Ian

I have since gotten rid of that truck.........I can't remember what it was but I do remember looking it up on here http://www2.dana.com/expertforms/departid.aspx
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  • 3 months later...

you can get the part from Harbor Freight for 20 bucks do not want to post urlalso get a axle from Boyd Millitary parts .. better deal and they can make it your way .. I have bought from them for 30 years and had good luck with them ... I do not want anyone thinking I am posting for them .. just done a lot of off road and mudding .. and going places I want to get back from .. thats allnot bad for my first post on the forum ... hope I can help out and learn more

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  • 1 year later...

My old girl gets a drooling rear seal about once every year. I always though it would be a hassle knowing the torque values and tools needed to do the job so I just took it to the dealer and about $150 later it was done.The the last time I had it at a dealer, I stood outside the bay and watched the mechanic change the seal out. It took him longer to get the drive shaft off than to change the seal. All they use is a cheap 3/4 drive, hammer the nut off, tap the yoke off, change the seal, yoke on and hammer the nut back on. Simple as that, takes a couple of minutes.I asked the mechanic about all this and he was pretty straight forward about it....there are no crush sleeves, it's all shims, blast the nut back on and be done with it. The nut will only go so tight, and it will be tight enough, easy enough.So now I do it myself at home, 20 minutes and it's done. Cheapo 3/4 drive impact puts out about 900 - 1000 lbs ft of torque, hammer it on.Have never had an issue with either my truck or all the buddies of mine who come over and borrow my junk to fix their rear seals.I know it's probably not the right way to do via "the book" but it works and I'm not doing it any different than my local dealer(s).Jeff

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I just did my pinion seal on my '81 chevy K20. Ill have to read up on the dana 70 & 80 pinion nut. On my 14 bolt 3/4 ton chevy rear axle. I used a small chisel to mark the location of the pinion nut, the pinion shaft end, and the yoke. And also counted the nunber of threads showing at the chisel marks. You need to do this to get the nut back on exactly where it was, so the pinion bearing preload is the same as it was when you reinstall the pinion yoke nut.

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The spacers and shims between the bearings set the pinion bearing pre load. The position of the nut doesn't matter and the number of threads showing shouldn't change. The 14 bolt corporate is set up the same way, just hammer the nut on with an impact and its done. I always use loctite just to be safe, but have never had an issue. Setting the pinion depth is a completely different story. Sent from my DROID BIONIC using Tapatalk 2

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  • 6 years later...

Big help smokeythedodge.  This is what a trash bag full of yard debris can do to a pinion seal in less than an 1/8th of a mile.  I'm not a happy camper.  But at least I got some preliminary info.  I knew there were a few different seals, but I really wanted to confirm the socket size, and that it needed to be a ridiculously thin wall socket at that.  Full synthetic oil has only been in there for two weeks... curious how much I lost in the 15-20 miles it took to get it back to the house.





Edited by Shainer
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Ouch, that was painful to look at.  


I too just marked the position of everything and tightened the nut back down to where it was before.  My torque wrench only goes to 150lbs.  I also used an old idler pulley as a seal driver to install the new seal, it was the perfect size and knocking the bearing out of the center allowed it to clear the pinion shaft.  Sometimes I'm glad I never throw old parts away.    

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On 11/10/2018 at 6:53 PM, Shainer said:

This is what a trash bag full of yard debris can do to a pinion seal in less than an 1/8th of a mile.

Kinda like a fishing line on a behind a prop

On 11/11/2018 at 4:06 AM, NIsaacs said:

This is what happens when you run over a mattress….https://www.youtube.com/watch?v=cDfA8idkUlA

Look on their faces, like now what.... priceless....

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I got the seal replaced.  Would have been a snap but the appropriate puller was at a friends shop, so I fabed one up.  What surprised me was how much trash was jammed behind the yoke shield.  It completely ripped every bit of the seal off the metal flange.  I lost a little over 2 quarts in the 15ish miles it took to get back to my place.  Sad sight when you pull into the shop to see perfectly clean golden gear lube just spilling out the pinion, well until you see the mess it made.  For those interested any standard 3/4" drive 1-7/8" socket will work.  Impact may be tight as smokeythedodg demonstrated.  I ordered a Performance Tool W34560 3/4" Drive 12-Point SAE Standard Socket, 1-7/8" off Amazon.  Would have preferred a 6 point socket but I could get that guy delivered the same day I ordered it.


The black is not the seal.  That is wadded up commercial trash bag.  Embedded in that are wood chips.  




Few pieces of scrap steel, 7/16-14 all thread with a taper for the pinion, a few welds, and some gear lube got the job done.



Few shots of the carnage.  Most of that is the trash bag, and more wood chips.  I didn't see any signs of debris making it to the pinion bearing.  During operation the oil flow constantly came out the pinion so in theory the debris would have to swim upstream to make it to the bearing.




Couple of success shots.  Yes anything that comes off gets blasted, etched, and painted.  It's a problem I'm learning to live with... I have gallons of primer and semi flat black.




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