• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Select Trac NP242

anderld47

NAXJA Forum User
NAXJA Member
Location
California
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
 
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.
 
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.
 
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.
 
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.
 
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
 
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:
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.
 
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.
 
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.

Interesting about ATF evaporating secondary to foaming.

Thanks Sidewinder CC
 
Interesting about ATF evaporating secondary to foaming.

Thanks Sidewinder CC

Very interesting, maybe this is why every TC (Even the clean looking ones) I pick up in the Junk Yard's fluid is low.
Maybe I'll switch fluid in my 2001 NP242 to 5W30 synthetic Motor oil or synthetic 75W90 Gear Lube.
 
still quiet @ 240K miles.

have problems disengaging though, I'm sure it needs new nylon pads on the forks.
 
Very interesting, maybe this is why every TC (Even the clean looking ones) I pick up in the Junk Yard's fluid is low.
Maybe I'll switch fluid in my 2001 NP242 to 5W30 synthetic Motor oil or synthetic 75W90 Gear Lube.

Don't go heavy. Don't forget you have to operate in colder climates. I think 5W-30 conventional would be max. I say conventional simply because I don't know if the seals in the TC will tolerate syn oil.

If you do switch I recommend that you drain, fill with motor oil, operate for a short hop then drain and refill in an attempt to un-mix the fluids.
 
Back
Top