NP231 whine

so my NP231 developed a whine the other day.

situation:
I was on an icy road, put it in 4hi.
loud whine could be heard.
shift back into 2Hi- whine goes away.

pull case apart:
fluid has a grey tint to it
magnet has really thin shavings that just feel like grease, but are magnetic
Chain NOT stretched
rear main bearing is good
front main bearing is good
front needle bearing (rear half of case) has some in/out play, not sure if that is normal
pump screen has some small shavings in it.

other issues:
generall it will not shift from 4hi-2hi while moving or under power, I usually have to let off the gas and coast a bit.


thoughts?

mine whines in 4lo but cant find anything wrong just think its the gears and chain. just put some thicker fluid in it

beastlydumass said:

mine whines in 4lo but cant find anything wrong just think its the gears and chain. just put some thicker fluid in it

Click to expand...

what fluid are you running? i was running ATF as per the manual.


it just seems strange, it has never whined in 4hi before that trip. I have heard it in 4lo, but never that loud either.

I wouldnt run thicker fluid, the little pump looks quite frail

Don't run thicker fluid in it, the case and internals are designed to use ATF. And as souske stated the pump won't survive fluids ... which will burn up the case quickfast.
Whining in 4lo is normal, the case should he relatively quiet in 4hi and should shift in/out of 4hi/2hi up to 80km/h (50-ish mph) without much issue (the odd time expect a bound that may cause shifting issues).

If you have whining and shiftirng problems ... pop it open and inspect the range fork and hub/assembly. Something has worn out, may be as simple as the plastic bushings.

X2 on the range fork. When I did the SYE on mine the range fork pads were missing and the fork itself was wallowed out.

after going through the case, I'm pretty sure the whining is from it not being shifted correctly.

either the pads are more worn out that I think, or the linkage is out of adjustment.

I'm gonna pick up a set of pads today and re-assemble it. I'll probably end up getting a novak cable shifter since I think my t-case raise has exceeded the geometry of the stock linkage.

What kind of whine are we talking here?


Does it go: But Blaaaainnee said......

souske said:

What kind of whine are we talking here?


Does it go: But Blaaaainnee said......

Click to expand...

jealous much?

:rattle: