1985 Nissan 720 4x4 rear Differential gear oil.

[Thomas Perkins]

HI ya'll.What kind of gear oil is used for my rear differential (rear end).C200 type.FSM says API-GL-5.What is the best type to use here in Georgia.

Edited July 15, 2023 by Thomas Perkins

[datzenmike]

80w is good from freezing to just over 100F. Any name brand is fine.

[Thomas Perkins]

Thanks Mike.The reason I asked is cause my oil seal back there is leaking and I just ordered 2 from the Nissan Dealer.I bought a extra one.The part number is C8189-N3100..They still have them.It has been leaking not long cause I was under there not long ago,wiping it down under there,getting the dirt build up off.It had oil on the bottom of gas tank and some on muffler.I seen that it was coming out of rear differential at oil seal.They were only 9.58 each plus I use Courtesy parts,they only charge 4.34 for shipping.Other Nissan places are 8 bucks or more.Mike,how do I take the seal out and install new one.Do I need special tools.

[datzenmike]

I did one on an H-190, C-200 has to be similar. Take driveshaft off after marking position. Mark the pinion nut position so it can be torqued back into this original position and remove pinion nut. The splined flange can be driven off by repeated hard tapping from the back with a large socket or something suitable, or a puller. Drill a small hole in the seal and screw in a wood screw. With something to grip onto now, use vice grips to pull/pry the old seal out. Don't let the tapered bearing fall out. Grease the new seal lips and install. It's kind of hard to drive the new seal in with the pinion sticking out. A very large socket would work. Or a block of wood with a large enough hole to fit over the pinion end and tap into place.

 

Tighten the pinion nut 94-217 ft lbs. This is actually a process with constant checking to get the correct pre load of 9-15 in lbs. The pre load is a measurement taken with a torque wrench on the pinion nut. 

 

I think we can skip this as it involves replacing the crush sleeve inside and I should imagine the axles must be pulled. The pre load is the force needed in inch pounds to begin turning the pinion. I should also imagine that if the nut is torqued back into place and the previous marks aligned it should be very close to the original set up.  

[Thomas Perkins]

Thanks Mike.I will give it a go when the seal comes in.They both use the same seal.H-190 and C-200.

[datzenmike]

Did not know.

[Thomas Perkins]

We'll,I went and got a quart of the 80 W gear oil.I used a 1/2 drive ratchet and got the plug off.Stuck my finger in the hole and it was about full.I topped it off with just a little bit.My FSM says it holds 2 5/8 pints.Then I got my water hose,bucket with Dawn water,a rag and a long handle brush and cleaned the whole underneath.Spit shined it.Then I washed my truck and wife's car in 98 degree Temperature.Now I am going to put a ignition coil on my Stihl weed eater.Now that it is spotless under there.I will drive it and see what is happening under there.I will go to Dairy Queen and get us a Strawberry Milk shake.That gear oil stained the gas tank as you see.Going to put some Meguiar's Wax on both vehicles.I haven't used this type yet,last type was Meguiar's Gold which was real good.

Edited July 15, 2023 by Thomas Perkins

[Thomas Perkins]

That ignition coil on my weed eater had so much crud on the 2 connections that it lost spark.

[Thomas Perkins]

Hi ya'll.I checked my rear differential after I got back from the store today and I do need a opinion seal.Their is a large nut that I will take off.I went on Nissan parts deal and here are the dimensions that are listed in inches.1.6 x1.5 x 0.8 inches.So what size socket do I need.Is it a 13/16.Or 20 or 21 mm.It says 20.32 mm.I will have to go buy one.May need to get a set.

Edited July 18, 2023 by Thomas Perkins

[720_Jeff]

20 hours ago, Thomas Perkins said:

Hi ya'll.I checked my rear differential after I got back from the store today and I do need a opinion seal.Their is a large nut that I will take off.I went on Nissan parts deal and here are the dimensions that are listed in inches.1.6 x1.5 x 0.8 inches.So what size socket do I need.Is it a 13/16.Or 20 or 21 mm.It says 20.32 mm.I will have to go buy one.May need to get a set.

I'd just buy the three sockets, just in case.  Which ever sockets you don't use, return to Home Depot or Lowes, since both sell single sockets.

 

[Thomas Perkins]

Thanks Jeff,I will do that.My seal is on it's way.I guess I will use a puller to get the flange assy off.My FSM is no help.My Haynes is better.Have you ever replaced the seal before.I will use lock tight on the big nut and 4 screw holding the drive shaft on.I will take pictures when I do this.

[Thomas Perkins]

WI am glad that I have a Nissan/Datsun Pickups 1980 thru 1991 Haynes Repair Manual.It shows how to replace the opinion seal on the rear  differental.The FSM does not.I like my Haynes way better.The 2wd and 4wd are the same when replacing the seal.Same seal and big nut.I will use my white out and mark everything.Put a screw driver in the u- joint to keep from moving when removing 4 bolts holding drive shaft on and rest it on my jack stand.Get my puller and remove flange and a screw driver and pry off seal.Use medium lock tight on big nut and 4 bolts.I did buy another big nut from Nissan.You never know.Nissan has changed the big nut.The part number has changed.It was about 6 bucks.Here are some pictures.

 

Edited July 19, 2023 by Thomas Perkins

[datzenmike]

My '84 FSM shows how to replace the front seal on the H-190 and the C-200. It does show taking the pinion out to do it. Not the way I did it.

[Thomas Perkins]

I will look and see what the front looks like but my Haynes shows it good.The seal is suppose to be here Friday.Wall mart has 9 sockets for 13 bucks So it would cost 26 to get standard and metric.Wonder if I will need deep well sockets.I will check out my FSM and see the front differential.

Edited July 19, 2023 by Thomas Perkins

[Thomas Perkins]

Lo Thanks Mike.I found out how to replace the oil seal.I was looking in the wrong section.It shows a tool.J-25774A,that keeps the axle from moving when removing the nut and Installing nut.I have the puller.Also shows a tool to knock the seal in.J-25273.To get seal out it says pry with screw driver.Says to lubricate  seal with gear oil and it install it. This procedure is from removing everything out of rear differential.Wonder if Auto Zone has these tools you can borrow ,just put a deposit on them.I borrowed a tool from them before it was a 60 deposit.

[datzenmike]

Yeah that's it. Dismantling the differential was more than I wanted to do. I left the pinion in  place and either pried the seal out around it or drove wood screws into the seal and used them to pull it out. I was worried about the tightening torque. I just leaned on it. Everything worked fine after and the leak was gone.

[Thomas Perkins]

Thanks Mike,I will do that.

[Thomas Perkins]

Hey Mike.It says to torque pinion nut to 94-217 ft. lbs.So what do I need to torque it to.Should I get a 1/2 inch torque wrench.I have a 3/8 torque wrench that goes from 0-75 ft. lb.I use this one to torque bolts on my valve cover.Walmart has a 1/2 drive that goes from 30 -150 lbs.Do you think this one will work or I need one with more torque.

Edited July 21, 2023 by Thomas Perkins

[Thomas Perkins]

The bad thing about getting my mail.I am on the back end of the route.I get it between 4pm to 7pm.

[datzenmike]

55 minutes ago, Thomas Perkins said:

Hey Mike.It says to torque pinion nut to 94-217 ft. lbs.So what do I need to torque it to.Should I get a 1/2 inch torque wrench.I have a 3/8 torque wrench that goes from 0-75 ft. lb.I use this one to torque bolts on my valve cover.Walmart has a 1/2 drive that goes from 30 -150 lbs.Do you think this one will work or I need one with more torque.

 

Well this is the thing. It's torqued and the preload checked. If the pre load isn't in spec then the torque is increased and checked. You keep going till the preload is correct with 217 ft lbs, the upper limit. 

 

If you haven't removed the nut, mark it's position so you can tighten it back till the scratch marks lines up. That's about all you can do.

[Thomas Perkins]

Thanks.Mike.

[butter fingers]

if you are leaking from the rear end Tommy maybe a doctor can help you ? LOL butter fingers 

[Thomas Perkins]

Butter fingers,he said I am a hopeless case.But any way.My oil seals came in.I took the drive shaft loose and put in on my jack stand and out of the way.I got my big adjustable wrench and measured the size of the pinion nut which I was going by mm's.And the size was 26 mm and they don't have any.So I did the conversion on google and the standard size is 1 1/16 inch.I did mark everything.It was marked on one side cause back in 2017,Ronald installed a transmission and a new yoke.But the pinion nut was not marked cause he didn't put one in.I got a hold of a old class mate that worked here at the Nissan dealer.He has retired.He worked there 31 years.He said I will need a flange tool to hold it as I loosen the pinion nut.He also said I will need a impact wrench to loosen nut cause it it torqued to about 250 lbs.He said someone is using his.So Mike,how did you loosen the nut and tighten it.He also said to check torq before removing nut and turn it and it should be the same when nut is tightened and re torqed.The book says that too.He also talked with Eric at Nissan.He still works there.We are good friends.I read a Nissan Forum and someone said you can use your e brake to hold the flange still.Also heard it could mess it up.What do you think Mike.It took 2, 17 mm wrenches to take the drive shaft bolts off.He used lock tight on them.Bobby says Nissan has a special tool that they used to hold the flange and loosen and tighten the pinion nut.I may go visit Ronald tomorrow and see what he says.

Edited July 22, 2023 by Thomas Perkins

[datzenmike]

i had the wheels on the ground and the e brake on. In theory loosening torque should equal tightening torque I like the idea of a scratch mark. Your pinion nut should be somewhere between 94 and 217 ft lbs. to  set the pre load. If originally it happened to be 100 and you tighten to the 217 max then the bearing will be too tight. Inside is a crush sleeve that looks like a small length of exhaust pipe. Tightening the nut crushes and slightly squashes the 'pipe'. I guess the crush sleeve acts like a compressed spring against the pinion bearing, somewhat. If over tightened you can't loosen it, it has the be replaced, so it's a one way adjustment.

[Thomas Perkins]

Update.It has been raining here since last night.What I did when I first started was put my big tarp down under the level ground under the trees and drove on it so it won't move.I had to get my blower and blow the rain water off of it. I put in gear and put the e brake on.I got my 1/2 inch breaker bar,it is 16 inches long,put the 1 1/8 deep well socket on it and it turned fairly easy.I did mark everything,I counted the threads before I started and there were 4 showing.It took 11 and a 1/2 turns to get the nut off.Then I got my puller and got the flange off.Now it's time to get the oil seal out.