I am currently putting in my 2nd input shaft bearing in my 1995 Nissan Hardbody XE King Cab 4x4. Does this tie to the oil level issue?

I have seen a few posts about this, but only concerning the 6 cylinder engine, it appears. I have found one TSB that I didn't have to pay to get, but it tied back to the 6 cylinder engine.

Can anyone tell me whether or not my 4 cylinder is running a transmission with the same low oil level problem? Or can somebody put me on a site where I can get the full TSB's without having to pay for them?

Thanks.

Hud

more than likely it does. I didn't know the issue was specific to v6 trucks, I thought it affected all of them. best way to avoid it is to add another qt throught the shifter hole or park the truck on the side of a hill and then add the extra qt.

I have the 4-banger, also. I roasted a input EVERYTHING one time just after a rebuild. It turns out that it was low on oil while the t-case was overfilled. It later became apparent that the tranny oil was exiting into the t-case through a ripped FRONT T-CASE SEAL.

That MAY be your problem.

quote:

Originally posted by Packman5280:
more than likely it does. I didn't know the issue was specific to v6 trucks, I thought it affected all of them. best way to avoid it is to add another qt throught the shifter hole or park the truck on the side of a hill and then add the extra qt.

Got it. Thanks for the info.

quote:

Originally posted by Reserector:
I have the 4-banger, also. I roasted a input EVERYTHING one time just after a rebuild. It turns out that it was low on oil while the t-case was overfilled. It later became apparent that the tranny oil was exiting into the t-case through a ripped FRONT T-CASE SEAL.

That MAY be your problem.

My trans level was fine, so I don't believe it's leaking into the t-case. Thanks for the info. Did you put the extra oil in your trans?

Hud

Yes. I put an extra 1/2 qt. or so in through the shifter. Worst thing that can happen is that some may drool out by the shifter and run down the side. Better than a burned-up input bearing.

Maybe your pilot bushing (in the flywheel) is shot, allowing the input shaft to move around too much.
I recall a thin washer and circlip that goes on the shaft before you install the input cover. Make sure that they are there.

quote:

Originally posted by Reserector:
Yes. I put an extra 1/2 qt. or so in through the shifter. .

iT might be more like a quart and half extra.

What were the symptoms of the shot bearing? Was it starting to whine?

I'm on my 3rd tranny...first two both went out from shot countershaft bearings. Not sure about the terminology here...is the countershaft the same as the input bearing?

The input shaft bearing in mine whined slightly for a day before failing catastrophically.

The countershaft is below the input/main shaft if I am not mistaken.
The input shaft is the one that sticks out the front.

People have always said it's the countershaft bearing that fails due to either lack of lubrication or the wronge type of lube.

The input bearing is the bearing that is on the transmission input shaft, which is the shaft that splines to your clutch disc. The input bearing is also the bearing located highest in the transmission, being on top and up front, which would have the greatest tendency to be "starved" for oil. When your input bearing is bad, you can really hear it at idle in neutral with the clutch out; when you push the clutch in, the noise will go away as long as your throw-out bearing is okay.

I do have some good news for the forum. As as last ditch effort to find the root cause of my two input bearings going bad, I stopped in at my local Nissan dealer and spent a few minutes with a technician on their shop floor. He had never heard of a problem like this. He pulled up a glossary of technical service bulletins on 1995 4WD trucks, and lo and behold, I found the "other" TSB I hoped existed, which covered the 4 cyl. trucks with the FS5W71C transmission.

There are two technical service bulletins out there on our trucks, and they cover 1986.5-1996 4WD trucks. Their numbers are NTB97-009a, and NTB97-018b (the a and b are amended versions of the -009 and -018, containing parts descriptions and such). In both cases, the service bulletin covers a whine noise on acceleration, which is caused by a lack of oil to the main and counter gears (and, consequently, main (input) bearing). In both cases, the oil level was increased.

For the FS5R30A transmission (backs up the V6), the oil level went from 3.6 to 5.1 quarts; for the FS5W71C transmission (4 cylinder), the oil level was increased from 4.2 to 5.2 quarts. At least now I know for sure what happened to my bearings. I suspected oil starvation from the failure mode of the bearings, but now I know for sure.

I'll try to post copies of the TSB's; I'll have to scan them first at work Tuesday. Hope this helps everybody.

Hud

hud,

did you say you've replaced that bearing yourself?
do you have any advice or tricks for the rest of us that need to replace this bearing?

I'd like to know "how to" as well.

As far as replacing the bearing goes, I did implement a trick this go-around. Previously, I had to pull the mainshaft (input shaft) bearing, countershaft gear and bearing, and then the mainshaft. I used gear pullers, and what a pain in the butt. It worked, but it wasn't easy.

The second time around, I was determined not to have to pull all the countershaft "stuff" to get this job done. The first thing I did was pull the front adapter plate off of the transmission to expose the mainshaft bearing and all the gears. Once I had this done, I covered everything with towels as much as I could, and then took a side grinder with a 1/32" cutting disc on it and slit the outer race of the input bearing in 2 places 180 degrees apart. To keep from damaging the input shaft gear, I turned the cutting disc on the helix angle of the gear and cut the outer race almost all the way through.

Once this step was complete, I took a hammer and broke the outer race off (doesn't take much force). I then cut the ball retainer in two places and got it and all the balls out of the way. I was then left with the inner race of the mainshaft bearing on the mainshaft.

To remove the inner race, I took my acetylene torch (recently acquired), and heated the inner race enough so I could tap it with a chisel and get it off the input shaft. This doesn't take much heat, and if you heat the inner race directly, you won't damage the shaft or gear. It was actually easier than I thought, and a simple propane torch like plumbers use would work fine also for those who don't have acetylene. Remember, keep the heat on the inner race, and turn the input shaft while heating the inner race so you can heat it fairly evenly. The inner race will then tap off with a regular chisel; it's not hard at all to do.

After this is done, you are ready to put on the new bearing. I made sure everything was clean, and I took scotch brite and cleaned up the input shaft journals so it would be perfectly clean. The next thing to do is put the new bearing on, which is very simple. Take a pie tin, put the bearing in it, cover it with aluminum foil (to keep the smell in), and pop it in a preheated oven on about 325 degrees for 20 minutes. Using oven mitts, take the bearing out of the pie tin and slide it over the input shaft. Heating the bearing is the most effective way to get it on, and you won't damage the heat treat. These bearings are made out of a very high carbon steel (probably 52100), and they don't temper out until around 700 or so degrees.

Once I got all this done, I put the adapter plate back on, put on a new front cover gasket and input shaft seal, and re-assembled. Once installed, I filled up the transmission through the shifter hole. Everything has worked fine, and I don't anticipate any more problems with it.

If anybody else has any questions, let me know.

Hud

That's an awesome write-up. I would love to see that, along with the bulletins, moved to the How-To section.

I have the 4-banger. I always suction out the rear section below the shifter. That allows me to get just over 4 qts in through the fill hole. I have always gotten at least 4.5 qts in there, but anymore I just pour 5 qts in through the shifter opening.

Great info! Thanks.