np242 fluid change

[Sidewinder CC]

i dunno, the oil pump is pretty frail looking, i wouldn't want to work it harder than neccesary.

I should of saiid pure beer vomit...uke:

 

[Jeepguy03]

Ya, also curious as to where you saw 3 quarts for the 242? I never saw that for mine in the manual or FSM.

Also does not explain for a complete tear down, the t-case does not retain fluid anywhere (in large amounts, small little puddles may still exist), like an automatic transmission does. Tearing it apart and putting it back together still uses ~1.5 quarts. And the fill procedure is always fill it until it starts leaking out the fill plug.

x2. I doubt a T-case will require twice as much fluid after a tear down. Does anyone else notice a difference between ATF+4 and regular Dex/Merc III?

I had ATF+4 in my NP231 then switched it out with Dex/Merc III after a year. The T-case seemed to not go back into 2Hi as easily when using the ATF+4. I'm wondering if it is the synthetic vs. non-synthetic? :dunno:

 

[Sidewinder CC]

x2. I doubt a T-case will require twice as much fluid after a tear down. Does anyone else notice a difference between ATF+4 and regular Dex/Merc III?

I had ATF+4 in my NP231 then switched it out with Dex/Merc III after a year. The T-case seemed to not go back into 2Hi as easily when using the ATF+4. I'm wondering if it is the synthetic vs. non-synthetic? :dunno:

The fluid call up for the 242 is Dexron II or ATF Plus, type 7176, which are both dino juices. The call up for the 231 is Dexron II or ATF+3, type 7176. The ATF+3 had more friction modifiers than the original ATF Plus 7176 but is still basically a dino juice - not like ATF+4, which is now a synthetic ATF with max friction modifiers.

The problem I see with using synthetic ATF in the TC is if the RTV used to seal the box is the old style RTV, the synthetic ATF will deteriorate the RTV and cause leaks (like my old TC). I think if a TC was reassembled using the newer RTVs designed for use with modern ATF (new Permatex Tansmission Fluid type RTV), ATF+4 may be the way to go.

 

[Jeepguy03]

The fluid call up for the 242 is Dexron II or ATF Plus, type 7176, which are both dino juices. The call up for the 231 is Dexron II or ATF+3, type 7176. The ATF+3 had more friction modifiers than the original ATF Plus 7176 but is still basically a dino juice - not like ATF+4, which is now a synthetic ATF with max friction modifiers.

The problem I see with using synthetic ATF in the TC is if the RTV used to seal the box is the old style RTV, the synthetic ATF will deteriorate the RTV and cause leaks (like my old TC). I think if a TC was reassembled using the newer RTVs designed for use with modern ATF (new Permatex Tansmission Fluid type RTV), ATF+4 may be the way to go.

Luckily my T-case doesn't leak. I just found it odd that the synthetic ATF+4 made the T-case harder to get back into 2Hi. It would shift fine, but if I went forward I'd still be in 4Hi. Shifting the trans into reverse made it go back into 2Hi. The Dex/Merc seems to have solved that issue.

I've only ran Dex/Merc in my previous XJs with the NP242s, this is my first NP231.

 

[Talyn]

If your output shaft seal on the trans is bad and the TC input seal not perfect either, you can get fluid leaking past the trans seal and ending up in the NP242, raising the level much higher than the fill hole.

Technically it won't do that as there is a hole at the bottom of their joint. Now, if that hole is blocked or some genius decided to seal the joint between the two with RTV (I have seen this done), then fluid can transfer beween the two if the seals are leaking.

 

[Sidewinder CC]

Luckily my T-case doesn't leak. I just found it odd that the synthetic ATF+4 made the T-case harder to get back into 2Hi. It would shift fine, but if I went forward I'd still be in 4Hi. Shifting the trans into reverse made it go back into 2Hi. The Dex/Merc seems to have solved that issue.

I've only ran Dex/Merc in my previous XJs with the NP242s, this is my first NP231.

You can switch back to Dex/Merc if you like but I don't think it's going to solve your shifting problems.

Search this forum for 231 shifting problems (various word combo's) and I think you will find some guidance on this.

When you say "2Hi" do you mean 2WD (2-Wheel Drive) and when you say "4Hi" do you mean 4 Lo (4-Wheel Drive low range)? I'm not a 231 driver but those that are that will chip in to help you wll need to know the proper terms.

I do know that it is normal to have to back up my 242 truck (reverse) to get the TC out of 4X4 sometmes.

 

[Jeepguy03]

You can switch back to Dex/Merc if you like but I don't think it's going to solve your shifting problems.

Search this forum for 231 shifting problems (various word combo's) and I think you will find some guidance on this.

When you say "2Hi" do you mean 2WD (2-Wheel Drive) and when you say "4Hi" do you mean 4 Lo (4-Wheel Drive low range)? I'm not a 231 driver but those that are that will chip in to help you wll need to know the proper terms.

I do know that it is normal to have to back up my 242 truck (reverse) to get the TC out of 4X4 sometmes.

Yeah I know that having to back up sometimes is a common issue on the NP242. I have an NP231 though. And no I meant "2Hi" and "4Hi". On the NP231 the shift pattern is 2Hi-4Hi-N-4Lo. NP242 is 2wd-4parttime-4fulltime-N-4Lo.

NP231:

NP242:

 

[Cottontail]

Mine smelt like burned sulfur and looked like black molasses when I changed the 87 np242 fluid. I considered getting it carbon dated, :shiver:, LOL!

Mine was the same. I decided not to carbon date it, and instead just dated it to the day the Jeep rolled off the assembly line!!!

 

[Ecomike]

Mine was the same. I decided not to carbon date it, and instead just dated it to the day the Jeep rolled off the assembly line!!!

LOL!!!:laugh:

 

[Sidewinder CC]

Yeah I know that having to back up sometimes is a common issue on the NP242. I have an NP231 though. And no I meant "2Hi" and "4Hi". On the NP231 the shift pattern is 2Hi-4Hi-N-4Lo. NP242 is 2wd-4parttime-4fulltime-N-4Lo.

NP231:

NP242:

See...I told you I wasn't a 231 driver. :laugh3: