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· Registered
56 Posts
Discussion Starter · #1 ·
So I looked under my truck on a whim yesterday and noticed oil splashed across the gas tank and the muffler. I sniffed it and it had the unmistakable stench of gear oil. I then noticed that oil was slowly dripping from the companion flange/pinion nut area between the flange and the drive shaft. So I've ordered a pinion seal and am preparing the do the repair.

Pinion seal replacement appears to be a fairly straight forward procedure so long as you follow the manuals steps to the letter. I have both the Haynes manual and the Factory Service manual. Are there any common mistakes I should avoid as this is my first pinion seal?

Thanks guys.

· Gone but not forgotten Member
5,733 Posts
Should not be a problem if you have the proper tools.
Let us know how it turns out.
Good luck!

· Registered
56 Posts
Discussion Starter · #3 · (Edited)
How I installed my pinion seal

The job wasn't too bad, but I accidentally ordered the seal for the wrong axle. Make sure you hold up the new and old seals together to double check the dimensions before you try to install a seal that is too large. I have the H190 axle. Here are the steps I followed in the hope that it assists someone else in the future. I chose to not change the crush sleeve as that requires the removal and complete breakdown of the differential. If I have done anything wrong, please correct me for sake of myself and the community.

*I recommend going over all the steps before starting and please recognize the difference between inch lbs and ft lbs.
1) Jack the truck up and support the rear on stands and be sure to chock the front tires. I also use two large blocks of overlapping 2x4's (about 1.5 ft cubed) as back up in case the jackstands fail.
2) Using paint or nail polish (the small brush is really handy for this) mark the drive shaft and pinion nut at one of the bolts for reassembly. This helps ensure the driveshaft is balanced on re-assembly.
3) Place the parking brake on and unbolt the driveshaft from the pinon flange (4 bolts)
4) remove the rear tires, release the parking brake and remove the brake drums. (this reduces the rotational force required to turn the pinion and comes into play next)
5) using an inch lbs beam or dial torque wrench measure the amount of force required to turn the pinion by the pinion nut. This is the bearing preload. For the H190 it is supposed to be between 10 and 20 inch lbs, but mine was down to about 5 as a result of wear. Write this number down for later.
6) Mark the pinion shaft, the pinion nut, and the pinion flange with nail polish for reassembly reference marks.
7) Place your 27 mm socket on the pinion nut and mark it with nail polish to coincide with the marks in step 6.
8 ) Use a strap wrench, chain wrench, or flange tool to hold the flange still while you undo the pinion nut with your 27 mm socket (make sure the marks all line up). Count the number of turns required to remove the nut and write it down with your preload measurement (mine required exactly 9 full turns to remove). DO NOT use the parking brake to lock the pinion in place. This will put undo stress on the gear and could result in a bad day.
9) Use a puller to remove the flange. If you don't have a 2 or 3 jaw puller you can rent one under the loaner program at Pepboys, Auto Zone or one of the other retailers. DO NOT use a hammer to knock the flange off. This could ruin your gears and your day.
10) Remove the three bolts holding the ABS sensor ring to the Diff housing. It has 3 bolts. Set it aside.
11) Remove the pinion seal with a seal removal tool or screw driver. Which ever you prefer, but be careful not to mar the mating surface of the housing or snag the bearings behind the seal.
12) Clean the mating surface for the seal on the Diff housing and the pinion splines on both pinion shaft and flange. I used some carb cleaner on a lint free cloth.
13) Apply a small amount of grease to the new seal and install it. If it starts off crooked you should start over.
14) Replace the ABS sensor ring.
15) Apply a small amount of RTV to the outside end of the splines on the flange.
16) Line up the marks on the flange with the marks on the Pinion and push the flange in place as far as it will go. DO NOT use a hammer to push the flange into place as you may damage the gears. The process of tightening the pinion nut will pull it the rest of the way safely.
17) Place a small amount of blue thread locker on the inside of the pinion nut.
18 ) Line up the painted reference marks on the pinion nut with those on the pinion shaft and flange and set the marked 27 mm socked in place to also line up. Turn the nut back a quarter turn and then clockwise to get it to catch. Check at 1/2 turn to be sure it has started to thread. If not try to start it a half turn back.
19) Holding the flange in place with a strap wrench, chain wrench or flange tool, tighten the pinion nut and socket the same number of turns required to remove it. You should finish with the lines on the pinon nut, shaft, flange, and socket all lining up.
20) Spin the pinion several turns in both directions to re-seat the bearings.
21) Using the inch pound torque wrench measure the torque required to turn the pinion. It should be approximately the same as the number you wrote down at the beginning.
22) Using your marked socket, tighten the pinion nut slightly to increase the preload. Do this in very small increments. The goal is to get the preload approximately 5 inch lbs higher than your recorded measurement. This is to make up for the tightness and resistance of the new seal. Do this in very small increments as it is crushing the crush sleeve a little more and you can't back the nut off to reduce preload. Backing the nut off will result in 0 preload. Do not exceed the maximum preload (my manual said between 10 and 20 inch lbs). It took only 1/8" turn (that's inches, NOT 1/8 of a turn) to get my increase. Also, DO NOT follow the factory pinion nut torque specs ( I believe it is 73 to 214 ft lbs. Those are for when using a new crush sleeve and you may not reach that with a reused crush sleeve. Preload is the priority. At this point there should not be any noticeable up down, side to side or in out play when you try to shake the flange. If there is, you may have worn bearings. There will be some minor rotational play (backlash) and this is normal.
23) Bolt up the drive shaft and flange.
24) Install your brake drums and wheels.

At this point I drained and filled my Differential. I did the drain and fill after because I wanted to use the same fluid for the initial and final preload measurements for consistency.

strap wrench
27mm socket
13mm socket
14mm socket
14 mm wrench
inch lbs torque wrench
ft lbs torque wrench
seal puller or screw driver
mallet to drive in the new seal
RTV silicone
blue thread locker
2 quarts of gear oil
fluid pump
carb or brake cleaner
Nail polish "borrowed" from the wife

So far I've put about 10 miles on the truck and everything is working fine. I will update after a tank or two of gas.

· Registered
56 Posts
Discussion Starter · #4 ·
Four months and about 4000 miles! The seal is holding and more importantly the differential is running smooth. The job was a little intimidating at first, but if you do your research before pulling things apart, you can do pretty much any repair on these little trucks.

· Registered
26 Posts
Hey, thanks for coming back and telling us how it went. I visit many forums and its nice to hear when members share what works. I appreciate it.

· Registered
105 Posts
Fishguy, thank you so much for this very detailed and super informative explanation. You are the kind of technician/mechanic I would want to actually do this job for me.

Because of the attention to detail required, I would rather do this job myself. However, I don't have the specialized tools and equipment to do this.

I have always had Nissan do my servicing, but I had one bad experience wherein the technician damaged my front axle seal when replacing a CV boot and he DID NOT admit it was his fault. He obviously, carelessly re-inserted the passenger side half-shaft into the axle housing and tore the seal. It was leaking like a sieve. His explanation: the splined shaft wasn't seated properly. So, that explained the PROFUSE leaking. It took 3 visits and a talk with the service manager before he admitted that HE damaged the seal. My compensation: a free oil change. Yeah!!!!! Thus, my apprehension.

Where are you located and would you consider doing this replacement? What would you charge? Or, can you recommend someone in the Baltimore area? Thank you!!!! Dane

· Registered
8,184 Posts
Don't think there are too many specialized tools. When I did this for a R200 rear diff, all I needed was a 3 jaw puller ($15) to get the flange off.

I did not know that the flange nut also preloaded the bearing. Good info.

Lastly, I think if you set the e-brake, you don't need to use a strap wrench to hold the flange while removing the nut.
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