Pinion Leak - Leave it / Fix it?

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I recently bought a 2004 Dakota. The previous owner replaced all fluids before my purchase. I have a slight drip in the rear pinion. 1 or 2 dime size drips over night. I think it is slightly overfilled and not sure what weight was used. (calls for 140w). Question that I can find an answer to that maybe somebody has experience with...Will the leak occur during driving or when sitting?? I have to take the truck on a 500 mile trip and am not sure if more oil will leak when moving or when sitting still? Also...I have read bad stories of folks replacing the seal only to make matters worse. Leave it?
 
Originally Posted By: Yota
1 or 2 dime size drips over night.


That's a big leak. It will also most likely sling oil while driving, so you are losing oil at a rapid pace. It needs fixed unless you want to burn up the rear axle.
 
I'd monitor the level after a specific mileage to ensure it remains nothing more than a drip. My wife took in our '98 Z28 back around 2005 and 90K miles for a small drip on the rear pinion similar to yours. They convinced her to have it addressed. It ended up costing over $1,000 which was insane. I'm pretty sure that leak could have been monitored. It would have made more sense to sell the car than pay that kind of bill.
 
It doesn't hold that much oil a few ounces a month would be catastrophic shortly unless topped up.
 
Low probability, but could be the vent is clogged... If so it'll push out fluid as it warms. Then drip off as it sits. Check vent. If vent OK, you gotta put a seal in it ...
 
Try stop leak first. If the pinion nut doesn't end up in the same exact spot, the crush sleeve will crush further if too tight or be too loose and the pinion depth will be off causing an improper mesh pattern.

Both my vette and ta leak and i'm reluctant to change the seals.
 
Last edited:
Originally Posted By: BrocLuno
Low probability, but could be the vent is clogged... If so it'll push out fluid as it warms. Then drip off as it sits. Check vent. If vent OK, you gotta put a seal in it ...


Vents are always a good thing to check first on a diff with signs of leakage. It seems like on half of the older trucks where I pay attention to it, it's either clogged or the tube is broken.

I would repair a drip to the ground personally. That's a sizable amount for a differential to be losing.
 
Pinion leaks are common on dodges. Improper pinion nuts, pinion nut torque, etc is all a problem on dodge trucks. There is recalls on it for the fullsize trucks. Might want to check into it for the Dakotas.
 
Thanks all for your insight and taking a few minutes to respond! Not being much of a mechanic - I have learned quite a bit reading your posts from all'yall.
 
Originally Posted By: turtlevette
Try stop leak first. If the pinion nut doesn't end up in the same exact spot, the crush sleeve will crush further if too tight or be too loose and the pinion depth will be off causing an improper mesh pattern.

Both my vette and ta leak and i'm reluctant to change the seals.



Incorrect, Crush Sleeve & Pinion Bearing preload does not effect Pinion Depth., Sure...You get it way loose & the Pinion can move forward & cause issues, Too tight will burn the Pinion Bearings up.

Check for play in the Pinion Bearings, Measure the Pinion Nut Depth with a Dial Caliper before removing the Nut, Tighten .002" deeper after seal replacement.
 
I would leave it for now and monitor the level. I regretted having a small pinion leak repaired under warranty long ago and have had a gear whine ever since. The dealer kept saying that's normal.
 
Mark the pinion nut in relation to the yoke. Mark the yoke to pinion spline location. Change the seal. Install yoke back to same spline alignment. Clean the threads, use a couple drops of red Loctite. Tighten pinion nut to same mark plus 1/4" of a inch extra. Changed a lot of pinion seals, never had a problem.
 
First , I would check to see if it is over filled . If not , top it off with what ever gear oil the manufacturer calls for .

Then monitor it .

I inherited a 1991 Chevy Caprice 5.0l automatic . Around 46,000 original miles . It developed a pinion seal leak , just setting still .

Went to O'Reilly auto parts for a seal . They listed 2 & I bought both . Jacked up the car & put it on jack stands . Dropped the drive shaft & pulled the yoke . Removed the old seal and installed the seal ( of the 2 ) that fit . Filled the diff back up with dino gear lube .

Been good so far . Took the other seal back for credit .

So , I recommend you replace the seal if it is leaking very much .

God bless
Wyr
 
Originally Posted By: oldhp
Mark the pinion nut in relation to the yoke. Mark the yoke to pinion spline location. Change the seal. Install yoke back to same spline alignment. Clean the threads, use a couple drops of red Loctite. Tighten pinion nut to same mark plus 1/4" of a inch extra. Changed a lot of pinion seals, never had a problem.


+1 ...... real pro
thumbsup2.gif
 
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