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  #1  
Old May 12th, 2016, 18:29
anderld47 anderld47 is offline
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Select Trac NP242

Would like to hear from those with Select Trac NP242 t-cases. What kind of t-case noise do you get in in Full Time 4WD compared to 2WD?

No difference...

Barely hear any difference...

Pretty noisy...

Have to jack up the stereo to hear my NIN cds....

Seems like it runs the gamut. Mine were always quiet until my last two. Trying to get a handle on is this a problem vs just the variability in t-cases.

Thanks
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  #2  
Old May 12th, 2016, 19:35
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ehall ehall is offline
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Re: Select Trac NP242

Planetary whine happens in everything they are installed in--transmissions, transfer cases, everything. Some 242s do it in FT, some don't. Some tcases will whine in PT or 4-Lo some won't. All of mine have whined in FT unfortunately, and loudly. My current one doesn't whine in 4-Hi much although it does have noticeable whine in 4-Lo.
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  #3  
Old May 12th, 2016, 19:44
anderld47 anderld47 is offline
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Re: Select Trac NP242

Again thanks ehall. I've always had whine in PT and 4-Lo. Guess until now I've been lucky.
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Old May 12th, 2016, 20:36
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Re: Select Trac NP242

explains the problem http://www.gearsolutions.com/article...ing-gear-whine
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  #5  
Old May 13th, 2016, 00:13
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1990JEEPXJ 1990JEEPXJ is offline
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Re: Select Trac NP242

Mine made a slight noise in FT. Was never an issue
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  #6  
Old May 13th, 2016, 01:21
anderld47 anderld47 is offline
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Re: Select Trac NP242

Quote:
Originally Posted by ehall View Post
Thanks ehall.

Seems like the "gear solutions" link is something used in the design phase of units.

Since the NP242 has been around for 30 years, do you think the noise variation is the result of the differences in replacement parts from various manufactures? I've had NP242 t-cases since the first XJ I bought in 1989. I'd never had any noise/whine until a year ago.
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  #7  
Old May 13th, 2016, 06:16
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Re: Select Trac NP242

Its just wear. When everything is new the tolerances are tight and the bearing surfaces are smooth, over time the bearing surfaces chip and the parts stretch out, allowing for more play. Things like condensation buildup and dirt and wear of the nylon parts its just unavoidable.
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  #8  
Old May 13th, 2016, 08:28
ThatGrimmJeeper ThatGrimmJeeper is offline
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Re: Select Trac NP242

When I had a new 2001 with the 242, I had no noticeable noise in full or part time high range for the 3 years I owned it.

I just bought another 2001 with the 242 and 167xxx miles on it and it has no noticeable noise in ether full or part time high range.
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  #9  
Old May 13th, 2016, 08:42
garr garr is offline
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Re: Select Trac NP242

I had one 242 that whined so much in full time I thought the front pinion bearing was shot!
I wondered if using a thicker fluid (Or using an additive) than Dex3 would quiet it down, although I never tried.
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  #10  
Old May 13th, 2016, 08:52
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Re: Select Trac NP242

Additives... I've looked for transmission additives that address gear whine and haven't found anything definitive, lots of stop-leak products that make seals swell up, and metal cleaners, and anti-shudder additives and other such, but nothing for noise that I can find. There are power steering additives for noise but they are mostly anti-foaming agents that fight aeration which isn't the problem with these, might try some anyway. Another possible source of noise is the synchro in the differential, might try something that addresses synchro whine in manual transmissions and see if it helps
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  #11  
Old May 13th, 2016, 09:38
garr garr is offline
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Re: Select Trac NP242

I've read some choose to run gear oil in their np231's with no issues, maybe synthetic 75w90 gear oil might quiet down a noisy np242?
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  #12  
Old May 13th, 2016, 10:01
anderld47 anderld47 is offline
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Re: Select Trac NP242

Quote:
Originally Posted by garr View Post
I've read some choose to run gear oil in their np231's with no issues, maybe synthetic 75w90 gear oil might quiet down a noisy np242?
Right now it's under warranty, so I wouldn't use anything other than factory recommended. I may just have to get used to the winter whine of FT 4WD. Seems to be a lot of variability in noise output in these things. Sometimes it's extremely quiet in FT but later gets whiny. Guess I'm getting whiny in my old age too.

Last edited by anderld47; May 13th, 2016 at 10:18.
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  #13  
Old May 13th, 2016, 10:46
garr garr is offline
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Re: Select Trac NP242

Quote:
Originally Posted by anderld47 View Post
Right now it's under warranty, so I wouldn't use anything other than factory recommended. I may just have to get used to the winter whine of FT 4WD. Seems to be a lot of variability in noise output in these things. Sometimes it's extremely quiet in FT but later gets whiny. Guess I'm getting whiny in my old age too.

Ok, so try a good synthetic ATF like Mobil 1, It may help.
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  #14  
Old May 13th, 2016, 10:59
anderld47 anderld47 is offline
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Re: Select Trac NP242

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Originally Posted by garr View Post
Ok, so try a good synthetic ATF like Mobil 1, It may help.
Pretty sure all ATF+4 is synthetic and has to conform to Chrysler standards to label it as such, but I could be wrong. Anyone else know?
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  #15  
Old May 13th, 2016, 11:33
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Sidewinder CC Sidewinder CC is offline
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Re: Select Trac NP242

My 242 is slightly more noisy in Full Time. Probably attributable to the differential in the TC working.

I use B&M Trick Shift automatic transmission fluid. This stuff is supposed to have extreme pressure and foam inhibitors. It's expensive.

Foam inhibitor is needed in the 231/242 TC's because the gearing in the TC whips the ATF to a foam which leads to evaporation of the ATF through the vent system, thus a loss of ATF over time.

Some folks use 5W-30 conventional motor oil in their TC to get around the foaming/vaporizing issue.
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