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NP231 Help. Doing SYE install and I am confused...

R

Rotorhead84

NAXJA Forum User
Location
Nebraska
Like the title says, I'm doing a SYE install and everything is going fine. Except when I take out the rear shaft and gear set I find these 3 gaps in one of the gears. I assume this is normal, but it appears to have grooves in it like something should go there?

IMG_2828.jpg


Also I am replacing all the shift fork pads and found something else interesting. The pad kit I bought doesn't have these type of pad in it. It has pads for a different type of shift fork. The Mode fork pads were correct.

IMG_2831.jpg


Somebody has certainly been in this t-case before. I'm guessing to change the chain as the case has some scarring on it from where the chain was hitting and the chain looks fairly new.
 
Rotorhead84 said:
Nothing goes in those empty places?
Click to expand...

Nope. That is your sychronizer hub. This diagram might help you, and there are FSM available to view online to help you out. The synchronizer sleeve goes on that hub to facilitate mode changes, I think it's part # 18 in the diagram here:

np231d_large.jpg
 
Odd, I just did an SYE swap-over (from a 94 ZJ w/ A500SE NP231, one of a kind case that won't fit anything else, to a 99 XJ NP231) tonight and I don't recall that synchronizer hub having any slots in it on either case.

I will take a look at the spare parts I ended up with from the old case next time I am at the shop. Checking my parts catalogs, the 94 case should have had the slots and the brass parts bails85 mentioned, while the 99 case would have just had the slots apparently... I don't remember it on either of them though.

Gotta say, the $15 lock-ring pliers I got in the automotive specialty tools section of Sears helped immensely. Should have bought those a long time ago.
 
kastein said:
Odd, I just did an SYE swap-over (from a 94 ZJ w/ A500SE NP231, one of a kind case that won't fit anything else, to a 99 XJ NP231) tonight and I don't recall that synchronizer hub having any slots in it on either case.

I will take a look at the spare parts I ended up with from the old case next time I am at the shop. Checking my parts catalogs, the 94 case should have had the slots and the brass parts bails85 mentioned, while the 99 case would have just had the slots apparently... I don't remember it on either of them though.

Gotta say, the $15 lock-ring pliers I got in the automotive specialty tools section of Sears helped immensely. Should have bought those a long time ago.
Click to expand...

Mine was identical to his, and I also was like WTF? until I realized that was not a drive/driven surface.

+1 on the tranny snap ring pliers, O'reilly's actually stocks those here where I live. I think they call them transmission snap ring pliers. They are the huge ones with knurled gripper ends, not the little prongs!

L4490.jpg


Geez that pic is huge hehe oh well.
 
Yeah, I ran to sears and bought some nice craftsman lock ring pliers as well before I started. Seemed to be the #1 recommendation for doing this job.


Thanks for the information everyone. I re-assembled everything yesterday and everything seems to work well, but I still seem to get stuck in 4wd and won't pop out on the fly.
 
have you re-attached you front driveshaft yet? If not switching from 2wd to 4wd and back will be problematic as the front yoke and output will always be in the worng place.

If you already have the shaft in place then re-adjust the linkage.
 
Rotorhead84 said:
Yeah, I ran to sears and bought some nice craftsman lock ring pliers as well before I started. Seemed to be the #1 recommendation for doing this job.


Thanks for the information everyone. I re-assembled everything yesterday and everything seems to work well, but I still seem to get stuck in 4wd and won't pop out on the fly.
Click to expand...

Another member was saying that the mode spring on the mode shaft (#48 big one you put on before attaching the big rear half of case housing) should be replaced if there is any question about its condition or you will have trouble staying in 2H. You sure that spring is in there and ok?
 
Devilfrog said:
have you re-attached you front driveshaft yet? If not switching from 2wd to 4wd and back will be problematic as the front yoke and output will always be in the worng place.

If you already have the shaft in place then re-adjust the linkage.
Click to expand...

My next move was to adjust the linkage. I'll give it a try and hope it works. I was having this problem since I bought the jeep. I was hoping that that replacing the plastic shoes would fix it as recommended to me on Jeepforum

X E Ryder said:
Another member was saying that the mode spring on the mode shaft (#48 big one you put on before attaching the big rear half of case housing) should be replaced if there is any question about its condition or you will have trouble staying in 2H. You sure that spring is in there and ok?
Click to expand...

My mode spring seemed to be in good shape. One end had a very slight up-turn or bend to it on the last 2 coils. I bet probably from being in the rear of the housing. I flipped it around and put that part against the shift rod. But the spring itself had no problems returning to its shape and didn't feel weak at all. And yes, I triple checked that I installed it. :looney:
 
Rotorhead84 said:
...And yes, I triple checked that I installed it. :looney:
Click to expand...

When I had done the perfect job of sealing my case backup I had one of those OMGZ! moments where I wasn't sure I put mine back in hehe - I did though and all is ok.
 
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