The Polar Bear - NP241 Upgrade

[Jeeptech01]

Damn gotta love a Gen III. Nice work on the y pipe.

[MineRunnerZJ]

Could you YouTube that video? Would love to watch it on my iPhone, and that website needs flash.

[downtowncb]

Thanks a lot guys!

damn man props! Now I'm super jealous because mine isn't done yet lol!

Hey man, no reason to be jealous of me haha, it took me 10 months to get to this point!

Could you YouTube that video? Would love to watch it on my iPhone, and that website needs flash.

That video isn't that exciting, I just start it up and rev it a little bit. I was hoping to get a better video today but I ended up having to drop the transfer case for a second time, it was still leaking. When I get it back together and started tomorrow I'll put a good video on youtube.

I have a noob question but which of these three types (or another) of RTV is best in your experience for sealing transmission fluid? I used the black type but it was still leaking...



I have to seal the surface on the above adapter to the mating surface of the NP242.

[ATL ZJ]

Out of those 3, black. Ultra copper is also pretty good. The best I have ever used is Toyota's FIPG (form in place gasket) that is $13 a tube. If all else fails, try that stuff.

[Brad S]

The last time I sealed up my t-case I used the high-temp red RTV. So far it appears to be working ok, but who knows how it actually compares to the black.

[AgitatedPancake]

I actually have a tube or two of Mopar ATF sealant, no idea where I got it from haha (not that I've used it in such an application, but it worked for hte tranny pan).

The grey RTV dealerships use (atleast dodge) on diffs would probably work, it actually takes some work to break the seal on the cover, it gets stuck GOOD.

[DaveJeep]

Mine is leaking again too for the 2nd time. I used Ultra Copper on it. Dropping it again this weekend.

Try using Anaerobic Flange Sealant by Permatex. It's meant for this.

[Jeeptech01]

Anaerobic will eventually leak also. As AP mentioned Mopar atf rtv is designed to stand up to.. well atf. Thats what I would use or mopar engine sealer. It is very similar to the "right stuff" carried by parts stores which is also the proverbial "cats ass" when it comes to sealing shizzle. HTH

[DaveJeep]

I thought anaerobic was the shit. What about just using gasket material with no coating?



Permatex® Anaerobic Flange Sealant
Flexible, gasketing material for use on rigid machined flanges with less than .015" gap. OEM approved – use where OE’s specify “anaerobic” gasket (cures in the absence of air). Withstands temperatures to 300°F (149°C). Eliminates preformed, pre-cut, paper, rubber and cork gaskets. Flexes with flanges that move in service.

Suggested Applications: Water pumps, thermostat housings, transmission pans, transmission case covers, transaxle casings, engine cases, timing covers, and o-ring replacement

[downtowncb]

I thought anaerobic was the shit. What about just using gasket material with no coating?

It came with a dry gasket that I originally installed and torqued down to the FSM value but that leaked as well. Last night I cleaned the shit out of both surfaces with lacquer thinner, applied a nice even layer of black to both surfaces, installed and finger tightened bolts per instructions, and came back an hour later and torqued to spec. Fingers crossed that'll do the trick.

[DaveJeep]

Anaerobic will eventually leak also. As AP mentioned Mopar atf rtv is designed to stand up to.. well atf. Thats what I would use or mopar engine sealer. It is very similar to the "right stuff" carried by parts stores which is also the proverbial "cats ass" when it comes to sealing shizzle. HTH

I have the Mopar ATF-RTV here and Permatex Anaerobic sealant. I used anaerobic on the t-case halve and no leaks there. I've never used the Mopar ATF-RTV but am a little scared to use it since the anaerobic worked on the t-case halves and says it's for transmission stuff. Not doubting you just want a little more input. Doing this on the weekend.

How long do you let the ATF-RTV dry for? And does it stick to aluminum? The tube doesn't have much info on it.

[AgitatedPancake]

It had no problem stickin to the body of the transmission for my pan so you should be good. I think either would be fine as you have personal experience with the other stuff working

[DaveJeep]

After looking it says the stuff I used is trans fluid resistant too. Permatex ultra copper

[Jeeptech01]

I have had a couple t cases that I sealed with anaerobic come back on me. The factory uses black rtv not anaerobic so I followed suit. There is nothing I hate more than a fawking recheck and going to black rtv has solved the issue. Just my experience. Also I always used the anaerobic before and never had an issue so it may have been a fluke when it leaked but I wasted enough time to chance it again. FWIW

[DaveJeep]

OK, that's all I needed to hear. Mopar ATF_RTV it is! Would it help if I cut out a paper gasket to go on there as well? Or just use the RTV?

[Brad S]

rtv

[Jeeptech01]

Rtv only IMO.

[downtowncb]

I drove it for the first time! So far the only problem is a really weird vibration from the transmission at low speeds... It is something I have never experienced before. But this is a newly rebuilt transmission. Any thoughts what it could be?

On a good note, holy shit this thing is way faster than it used to be! And it is in no way quiet haha. Video to come tonight.

[ATL ZJ]

I drove it for the first time?

My name is ron burgundy?

So far the only problem is a really weird vibration from the transmission at low speeds... It is something I have never experienced before. But this is a newly rebuilt transmission. Any thoughts what it could be?

On a good note, holy shit this thing is way faster than it used to be! And it is in no way quiet haha. Video to come tonight.

seriously though, we need video

and are you sure your flexplate bolts are super snug?

[downtowncb]

My name is ron burgundy?

seriously though, we need video

and are you sure your flexplate bolts are super snug?

Haha I wrote that on my iPhone. I just looked at the videos from today and they sucked, I'll get one of it driving and me getting on it tomorrow. As far as the vibrations go, could the fluid being overfilled do it? I just discovered it is way overfilled, I'll pump some out tomorrow as well as drop the starter and check the flexplate bolts.

[Jeeptech01]

Could be overfilled. Was it rebuilt with alto red or other hp frictions? Sometimes they take a bit to burnish in.

[downtowncb]

Could be overfilled. Was it rebuilt with alto red or other hp frictions? Sometimes they take a bit to burnish in.

Not that I'm aware of, just a standard rebuild. I got the fluid level dialed in perfectly today and it is still doing it. I checked the flexplate bolts, they are torqued to spec. In neutral when I rev it there are no vibrations so I know it's not the flexplate or torque converter imbalanced. When I put it in reverse or drive there is a very noticeable vibration when accelerating but not when coasting. I found the service manual and am going to drop the pan tomorrow and see what I can see. I took Drew, one of the owners of Poly Performance for a drive and he, like I, has no idea what the cause could be.

I washed this puppy today and started fixing the paint. Every square inch is covered in rust speckles from the carbide/steel dust. I started wet sanding it with 2000 grit and will then polish it afterwards. This gives you an idea what it looks like.



My test spot.



The end of the day.



Sorry, still no video. Trying to wait and get one with it running well. On a good note, the RTV appears to be sealing just fine!

[IndyZJ]

Are you sure the vib is in the trans and not the t-case/ adapter/ driveshafts/ axles?

Just throwing things out there. Who rebuilt the trans?

[ratmonkey]

My car gets a low speed vibe when accelerating after sitting for a while. Its the soft compound tires flat spotting where it was parked.

Throwing that out there as a possibility.
You've got so many adapters and custom work going it'll be very hard to track down. I'd start with mounts and driveshafts.

[MineRunnerZJ]

Good luck finding the vibration, hope you get that sorted out.
Congratulations on an amazing build, even if it had just a 360 the ZJ would be amazing! Can't wait to see how this thing performs in the rocks and on the street!