Leaky Pinion Seal on Rear End

[jmgtp]

Well, not a 60v6 but thats ok since we are in OT.

This is on my 2006 Dodge Dakota ST 3.7/4x4 4sp Auto
Truck has 80k on it

I'm leaving little stains in the driveway everywhere I park and from the best I can tell it is coming from the pinion seal on the rear diff. To replace the seal, I imagine I'll have to unbolt the u-joint, drop the driveshaft and remove the pinion nut.

My concern comes on reassembly. I believe there must be a spec'd amount of preload on the pinion bearing, meaning that the pinion nut has to be tightened to spec. I'm not sure if it uses a crush sleeve or not, and if it did would it be necessary to replace it? I've read that others (apparently this is a common problem on the Dakota) have used an impact gun to remove and install the pinion nut with little regard for preload or a torque spec - they report no problems after but an improper amount of preload may not show ill effects immediately either. Others still, use hand tools to remove the pinion nut and count out how many turns it took and ensure that on reassembly it goes the same number of turns.

Anyone have any experience on this? I'd hate to have to farm this out to a 'pro' and I flat out couldn't even afford to do that right now. Since the truck is my winter driver and I can't afford significant downtime I may just check the oil level and top it off for now.

[jmgtp]

Did some googling and found that the rear does in fact use a crush collar. From what I gathered the only 100% right way to do it, would be to pull the front bearing out of the diff, replace the crush collar, pull the axles and ring assembly out. And put exactly the correct amount of preload on it but tightening down the nut on the crush collar until it takes something like 20 inch pounds of force to turn the pinion - that's not 20 inch pound of torque on the nut but rather 20 inch pounds of rotation force to turn the pinion after it has been torqued.

This would be a whole world of work. I wouldn't even conisder doing it for and from what I read most 'shops' would even cheat their way around it.

It seems like most people changing the pinion seal in their garage (as well as small business shops) will mark the pinion nut and a corresponding mark on the carrier and count the turns to remove. On reinstall the pinion nut is torqued to match the original marks and then add another 1/8 turn to crush down a bit more on the sleeve.

Has anyone done this in their garage before? I'd hate to do this and then have the rear end start whining a few miles down the road!

[bob442]

I'll tell you what i have done countless times at my work. (successfully)
Mark the nut and pinion with a deep punch or cut (via die grinder) that wont dissapear, so when you tighten it back up you can tighten it exactly where it was, and take a good picture, or mental note of how many threads are showing past the nut, impact the nut off, remove the washer and yoke, inspect the yoke sealing surface, sometimes you can clean up the groove with sand paper, sometimes you have to use a slip sleeve, or having to replace the yoke, rather new or a used one. then remove the seal, before installing the new seal, pack the back of the seal with grease so the spring doesnt fall out when installing the seal, and whipe grease on the sealing surface that meets the yoke so it has plently of lube, and on the sealing surface that meets the housing, put a thing layer of red locktight and whipe it around with your finger to spread it out. install the new yoke (or reconditioned)and tighten the nut with a impact till you get close the the mark (and tight how it was) and give the yoke a few smacks with a hammer to ensure everything is in place and that the preload is proper. Doing this last step puts the tension that is built up on the yoke/pinion to anywhere on the assembally that isnt compressed. then double check to see that your nut is tight. i will garantee you will not be able to crush that sleeve with a 1/2 impace gun more than 1/8 of a turn. Garantee. then take it for a quick spin after you check the oil and ensure everything is quiet. now wouldnt be a bad time to chenge the diff fluid aswell.

[geoffinbc]

Yes hundreds of shops do it the way that is described above. Sleeve and axle manufacturers will tell you once a sleeve is used then it is toast. Shops disagree and reinstall everything as it came apart. But keep in mind that the sleeves job is to KEEP THE BEARINGS APART and tight to the nut. And old sleeve or new sleeve will not change the bearing preload, only the position of the nut will do that. So tightening the nut beyond where is rested before it not ideal, you will effectively be increasing the bearing preload.

[bob442]

yes this is true, but have any of you tried to squish a crush collar? you need a 5ft bar on a breaker bar, or a 1" impact gun. in my old shop they would get it "close" with a 10 ton press then do the rest with a 1" impact gun. so all in all, your not going to over tighten a crush ring easly at all.

[geoffinbc]

No what I am saying is make your mark to indicate where the nut was. Change you seal and then put it back exactly where it was. Don't add any extra because you could over load the bearings.

With a good 1/2" impact you can collapse a collar. But you need a professional one like MAC or Snap-On. I just did a couple on my Isuzu. It also helps to have a bar to hold the pinion flange still.

[jmgtp]

Thanks for the insight guys.

I have several 1/2" impacts, from a wimpyish Craftsman to a Ingersol Rand that I have yet to come across a fastener it can't break free or just plain break.
So, we have 2 schools of thought going here. One saying that if I am going to resuse the crush sleeve then I will need to tighten it just a bit past the original spot and the other saying that I want to tighten it to exactly the same spot. I guess the question is, what would be worse for preload, a bit too much or a bit too little?

To do the job, will I want to have the parking brake set to prevent rotation?

At 80k miles I think I will use a slip sleeve with the new seal so I don't need to be concerned about any groove that the old seal may have dug in. Honestly, right now there is snow on the ground, the streets are a salty mess and I need the truck so this job likely won't happen until the spring. It is supposed to be mild and rainy today so I'm hoping that cleans up some of the mess since I'd like to pull the truck into the garage (means taking a stored car out) and at least top off the diff oil.

[bob442]

I have several 1/2" impacts, from a wimpyish Craftsman to a Ingersol Rand that I have yet to come across a fastener it can't break free or just plain break.
So, we have 2 schools of thought going here. One saying that if I am going to resuse the crush sleeve then I will need to tighten it just a bit past the original spot and the other saying that I want to tighten it to exactly the same spot. I guess the question is, what would be worse for preload, a bit too much or a bit too little?

i didnt intentionally say to go past the original spot to apply more preload, but i was just stating its mearly impossible to go past with a 1/2" impact gun

At 80k miles I think I will use a slip sleeve with the new seal so I don't need to be concerned about any groove that the old seal may have dug in.

i would try not to use a slip seal if nessisary, there seems to be a fail rate with them sometimes, mostly the seal side. at 80km i can imagine a groove being cut, and even if its light you can get it out rather easy with some 220 grit and the palm of your hand and rotating the yoke with the other. then some 320 and some oil for a finish and its good to go.

[jmgtp]

Bob442, I read your original post again and I see where I misinterpreted. I believe the basics of what you said is that using a 1/2" impact I wouldn't be able to compress the sleeve by more than 1/8 turn, even if I tried. So the plan is to mark it, remove it, replace the seal and reinstall back to the marked position. Still not something I think I will do until its springtime since I can't afford downtime should something go wrong.

[bob442]

You got it park Pontiac


Sent from my iPhone using my iPhone at work cuz I have nothing to do

[jmgtp]

I had some time last night so I pulled the truck in the garage and lifted the rear end. The area of the diff housing near the pinion has a bit of caked on 'grease' like stuff but nothing out of the norm. I didn't see any tell tale signs of oil slung all over the place either. The seal on the back cover isn't leaking either. The fill plug is just a large rubber cap that pulls off. I stuck my pinky in and felt oil about 1/2" from the fill plug hole - since I only have the rear of the truck in the air it makes sense that it would appear a bit low since the fill hole wasnt level. So, I don't think it was low at all but I added a bit to it just to be sure. I feel better about it at least until the spring. Then I'll park on some cardboard and see if I am leaking or not.

I also found that the rear end links were LOOSE and that was one of my annoying rattles, so I snugged those down. On my last fillup I got a sad 11.4 mpg, this is a v6 mind you. I figured its been cold, I do mostly city driving and I use my remote start often. But, I decided to check a few other things of which one was to replace the spark plugs. Oh man did it need that. These are the worst shape plugs I have ever seen, no doubt the originals with 80k on them. They were worn down so bad that the gaps were more than 2x what they should have been. I put new, correctly gapped, Champions copper plugs in. It feels like it runs about the same, but I did notice on the highway it is downshifting less often. I'm hoping it turns out some better numbers on this tank!

[bob442]

well that makes me feel better about you putting off the rear seal aswell