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Well fudge

Cadden

Cadden

1/2 ton status
Joined
Jan 28, 2020
Posts
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Location
Oregon
1970 jimmy
np205 transfer case.

Took it to the sand dunes. Was all fun until all of a sudden I lost 4x4 and heard some clunking.

I think my new rear duragrip posi saved my ass getting back out and back to the staging area. Had to push that engine HARD to keep the tires spinning and not get stuck. But I made it almost over heating the entire way. Well not almost she was HOT!

ANYWAYS. Once back, I had an extremely difficult time getting it out of 4 low. Had to drop the clutch while yanking on the np205 shifter.

Once in 2 hi and hubs unlocked it drove fine the 2 hours back home with no issues or bad sounds.

What do yall think? Maybe just the front output shaft? Full rebuild?
I changed all fluids before I went on this trip.
 

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  • received_469498431737888.mp4
    4.4 MB
Losing power to the front is just on that shaft. Could be something haywire with the shift rail for the front? Maybe?
Check your front driveshaft to see if there is movement of the drive yoke in and out. Also look at the bearing in the rear cover for the front output.
Do you have the stock single shifter?
 
6872xtc said:
Losing power to the front is just on that shaft. Could be something haywire with the shift rail for the front? Maybe?
Check your front driveshaft to see if there is movement of the drive yoke in and out. Also look at the bearing in the rear cover for the front output.
Do you have the stock single shifter?
Click to expand...
Stock shifter. I'll double check the shaft for play. When I was replacing the seal the bearing looked ok to me on the rear output

20220317_181959.jpg
 
It sounds like the rear output is fine. The center of the aluminum cover , on the backside of the front output, is what I was referring to. That's a bearing. Your picture shows the speedometer cable hanging an inch or so away from the bearing in the center of the cover. If it has moved out of the cover compared to this picture, the shaft is moving and is pushing on that bearing.
 
6872xtc said:
It sounds like the rear output is fine. The center of the aluminum cover , on the backside of the front output, is what I was referring to. That's a bearing. Your picture shows the speedometer cable hanging an inch or so away from the bearing in the center of the cover. If it has moved out of the cover compared to this picture, the shaft is moving and is pushing on that bearing.
Click to expand...
Oh gotcha. Yea when it comes to transfer cases I'm afraid my experience is limited.
So that cover removes fairly simply right?
 
Cadden said:
Oh gotcha. Yea when it comes to transfer cases I'm afraid my experience is limited.
So that cover removes fairly simply right?
Click to expand...
Yes, it does. But don't concern yourself with pulling it, just look at the bearing.
The front output shaft is held in position by the front bearing and retainer. The yoke has to be tight on the shaft as well. If the nut backs off, or the front bearing gets worn, or the snap ring under the retainer is missing or get damaged, the front output shaft will walk in the case.
 
Were you able to verify only the rear wheels/rear driveshaft were spinning and not the front when you were in 4WD?
You couldn't get it out of 4WD because there was a unequal torque/load still on the xfer case. Usually putting it in reverse and moving back slightly will fix that. My 88 does that occasionally however, as mentioned, it could be a linkage misalignment.

You unlocked the hubs and it drove fine so I'm wondering if you broke something in the front differential?
I would put the front on jack stands, pop the front diff cover and look around while turning the tires with the hubs disengaged and engaged and xfer case in 2WD or neutral.
Just some thoughts......
 
With front yoke and cover removed,.I'm guessing it's not supposed to move that much
 

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  • received_1153142782221630.mp4
    4.1 MB
88Silverado said:
Were you able to verify only the rear wheels/rear driveshaft were spinning and not the front when you were in 4WD?
You couldn't get it out of 4WD because there was a unequal torque/load still on the xfer case. Usually putting it in reverse and moving back slightly will fix that. My 88 does that occasionally however, as mentioned, it could be a linkage misalignment.

You unlocked the hubs and it drove fine so I'm wondering if you broke something in the front differential?
I would put the front on jack stands, pop the front diff cover and look around while turning the tires with the hubs disengaged and engaged and xfer case in 2WD or neutral.
Just some thoughts......
Click to expand...

I thought the same buy the clunk sound comes from the transfer case.
 
Uhhh.. that's a surprise! You found out where the front output shaft gets engaged.

What all did you check before tearing into the case?

Was the front out yoke tight? Did it have a bunch of movement in and out?

Did you try driving it in 4 high and 4 low with the front shaft removed?

Did you check the front axle to verify that it doesn't have a problem that could be sending the noise up the front driveshaft?
 
6872xtc said:
Uhhh.. that's a surprise! You found out where the front output shaft gets engaged.

What all did you check before tearing into the case?

Was the front out yoke tight? Did it have a bunch of movement in and out?

Did you try driving it in 4 high and 4 low with the front shaft removed?

Did you check the front axle to verify that it doesn't have a problem that could be sending the noise up the front driveshaft?
Click to expand...
Front diff looks good as do axle joints. Front yoke didn't seem to have movement before I took the nut off, I understand now that removing it makes everything loose.

However, the front bearing just fell out when i took the rest out, with the snap ring still around it? I had to basically catch it.

20220906_140110.jpg
 

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  • received_440007441419271.mp4
    4.8 MB
Glad to hear that you are learning. These cases aren't super difficult.

That front bearing can get a little loose in the case bore. The oil can make it slide easily. It's hard to tell, but I wouldn't believe that it has been spinning much in the case bore, but check that and also check out how it rolls with your hands. It should feel smooth with only a small amount of misalignment play between the inner and outer races.
The snap ring looks good to me, and it was in the groove, obviously. The aluminum retainer holds the snap ring captive against the case, so a gasket under the retainer, at the case is mandatory.
Check the idler gear for excessive end play. I believe that it is only supposed to be a few thousandths, but I don't remember the exact spec. It had tapered roller bearings in it, so it shouldn't walk end to end much. (I honestly don't know if it being loose would give those problems)
I figure that since you opened it up, check stuff out! But we still don't know what caused the lack of power to the front yet.
 
Spyder's and gears look fine. Assume the driveshaft u-joints etc. feel good too.
Sorry, I dont have any other suggestions.
Good luck!
 
88Silverado said:
Spyder's and gears look fine. Assume the driveshaft u-joints etc. feel good too.
Sorry, I dont have any other suggestions.
Good luck!
Click to expand...
Thanks. Yea all new ujoints were recently put in. I'll keep digging.

Question, I have an opportunity to get a np205/sm465 setup out of an 85 ish blazer. It's got a hydraulic clutch. How difficult would it be to swap? This ol mechanical clutch wears me out in traffic lol

I know the spline count would be different so I'd likely have to change the clutch, or swap my 10 spline shafts in the swapped case right?
 
An '85 Blazer would have been a NP208 case. Only the one ton trucks got the 205 then. So there are several ways that parts could have been swapped. They could have put an older combination like yours in with the hydraulic bellhousing. Or found newer parts.
 
Ok. So the ONLY thing that was off to me, was how the front output bearing just fell out with snap ring still on it.

For example, I had to tap it in with a hammer originally, but when I was putting everything back together I would pop it out super easily. Snap ring and all

So I'm guessing the ridge/edge that holds the bearing with the snap ring is messed up.

Also putting all that in while T-case was still in the truck was a giant PITA!
 
I believe that pilot retainer is actually in the retainer cap you bolt on from the outside, once you remove that, the bearing can fall out.

Are you sure you didn't break a front locking hub?

Where is that clunking coming from? The direction can't be heard in the video.
 
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Whats the point of the snap ring on the bearing though?

And as far as I can tell the hubs aren't busted and turn shafts with wheels etc.
folkenheath said:
I believe that pilot retainer is actually in the retainer cap you bolt on from the outside, once you remove that, the bearing can fall out.

Are you sure you didn't break a front locking hub?

Where is that clunking coming from? The direction can't be heard in the video.
Click to expand...
 
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