I have a 2003 Jeep Rubicon that I have had since new, I have changed out the fluids a few times while under warranty with the recommended stuff. Now that its outta warranty would it be better to use an syn-oil in the t-case? I don't see the need for friction modifiers and stuff like that in a chain and gear Tcase.
Oil in T-Case instead of ATF+4
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I've wondered the same thing. I did run RP synchromesh in the NP231 in my 02 TJ but I didn't like the way it shifted. It would hang up when going from 4hi to 2wd.
ATF+4 only!
These t-cases aren't picky. As long as the oil is similar in viscosity to ATF (too thick when cold will do damage), and is slick enough for it not to stick in 4wd (tough to disengage), it's fine. Some say 5W-30 engine oil works well. Any ATF is fine too. If you want to try something different, go ahead, and see how it shifts.
My Tcase is the rocktrack NP241, a buddy of mine got an Atlas tcase and they sent it with Mobil1 5w20 I think in the box.
If you decide to go with a motor oil, use a full synthetic. 0w30, 5w30, 0w20, 5w20.. are some choices.
Full synthetic MTL's or MTF's can also be used. But, they usually are considerably thicker as the temperature drops and best reserved for southern climates.
The key to any gearbox life is <~30k or 2-3yr change intervals, keeping the level top offed regularly, and changing the fluid if your Jeep likes to go swimming. So, if you like to cross rivers, streams, and play in the mud, you're better off changing the fluid after every outing with something locally available.
Full synthetic MTL's or MTF's can also be used. But, they usually are considerably thicker as the temperature drops and best reserved for southern climates.
The key to any gearbox life is <~30k or 2-3yr change intervals, keeping the level top offed regularly, and changing the fluid if your Jeep likes to go swimming. So, if you like to cross rivers, streams, and play in the mud, you're better off changing the fluid after every outing with something locally available.
I'd run a PP 5w-30 in my 242 selec trac, would turn from gold to black in about 8-9K.
It did shift seemingly quicker from 4wd back to 2wd compared to ATF+4.
But for now I'm just sticking to ATF+4 at 30K intervals. Less work for me.
It did shift seemingly quicker from 4wd back to 2wd compared to ATF+4.
But for now I'm just sticking to ATF+4 at 30K intervals. Less work for me.
Originally Posted By: unDummy
Any full synthetic ATF will work fine. Nothing exotic about that transfer case. And, the RP Syncromesh, which is the same visc as ATF, will shift fine. Next time double check the level.
Level was fine.Don't forget that I use 4x4 in the Jeep weekly and I know how it normally shifts.
I ran it for 30K and checked the level at every oil change. It would "hang up" when going from 4x4 to 2wd. The lever would move and be in the 2wd position but it would still be in 4x4 for a few seconds then it would disconnect the front axle with a bang.
Any full synthetic ATF will work fine. Nothing exotic about that transfer case. And, the RP Syncromesh, which is the same visc as ATF, will shift fine. Next time double check the level.
Level was fine.Don't forget that I use 4x4 in the Jeep weekly and I know how it normally shifts.
I ran it for 30K and checked the level at every oil change. It would "hang up" when going from 4x4 to 2wd. The lever would move and be in the 2wd position but it would still be in 4x4 for a few seconds then it would disconnect the front axle with a bang.
I've ran RP SynchroMax with good results, and now run Red Line MTL.
Knock Dex VI off the list of synth ATF suitable for transfer cases. GM came out with a fluid just for transfer case use after they discontinued Dex III. Might be due to thin viscosity.
Chris - Over time, the shift fork pads will wear out in the case. If it's been sticking more and more over time, and a different fluid doesn't take care of it, the pads are wearing out. If that's the case, it's time to drop the t-case and split it open to replace them. If allowed to go too long with worn out pads, the shift forks themselves, as well as the surfaces they slide on, can be damaged, requiring a new t-case, or at least more extensive repairs.
I use Mobil 1 Multi-veh ATF in my '92 Wrangler's NP231HD. It's a case designed for Dexron II, so anything modern (ATF+4 or Mercon V are great choices) would be fine.
Please do not use motor oil. The pump is designed for ATF. Your buddies Atlas came with 5W20 because it's gear driven.
Please do not use motor oil. The pump is designed for ATF. Your buddies Atlas came with 5W20 because it's gear driven.
Originally Posted By: rslifkin
Chris - Over time, the shift fork pads will wear out in the case. If it's been sticking more and more over time, and a different fluid doesn't take care of it, the pads are wearing out. If that's the case, it's time to drop the t-case and split it open to replace them. If allowed to go too long with worn out pads, the shift forks themselves, as well as the surfaces they slide on, can be damaged, requiring a new t-case, or at least more extensive repairs.
Fortunatly switching back to ATF+4 fixed it. It's been 60,000 miles since I drained the Synchromesh out of it.
Chris - Over time, the shift fork pads will wear out in the case. If it's been sticking more and more over time, and a different fluid doesn't take care of it, the pads are wearing out. If that's the case, it's time to drop the t-case and split it open to replace them. If allowed to go too long with worn out pads, the shift forks themselves, as well as the surfaces they slide on, can be damaged, requiring a new t-case, or at least more extensive repairs.
Fortunatly switching back to ATF+4 fixed it. It's been 60,000 miles since I drained the Synchromesh out of it.
Chris - Shift quality definitely seems to vary a bit from fluid to fluid. Mine doesn't love to get in and out of 4wd below 15mph (other than 4lo), so I'm contemplating trying something different than ATF+4 at some point. Sounds like RP Synchromax isn't the fluid for it though.
Zaedock - As long as it's a light motor oil (no thicker than ATF when cold), the pump will be fine. IIRC, George at Transfer Cases Unlimited actually recommends 5w-30 synth engine oil. Putting in anything heavy, like gear oil, would be a bad idea.
Zaedock - As long as it's a light motor oil (no thicker than ATF when cold), the pump will be fine. IIRC, George at Transfer Cases Unlimited actually recommends 5w-30 synth engine oil. Putting in anything heavy, like gear oil, would be a bad idea.
Redline MTL is worth a try if you can get it. Amsoil makes a similar lube as well.
I used a mix of Amsoil ATF and MTL and that case is still going strong.
I would think that M1 10W30 High Mileage would be a very good choice for an ATF spec. T case.
I would think that M1 10W30 High Mileage would be a very good choice for an ATF spec. T case.
Originally Posted By: rslifkin
Zaedock - As long as it's a light motor oil (no thicker than ATF when cold), the pump will be fine. IIRC, George at Transfer Cases Unlimited actually recommends 5w-30 synth engine oil. Putting in anything heavy, like gear oil, would be a bad idea.
Originally Posted By: Tempest
I would think that M1 10W30 High Mileage would be a very good choice for an ATF spec. T case.
Once again, the New Process / New Venture Jeep cases are NOT designed for motor oil. Use what the manufacturer specs. A 5W30 engine oil will be almost twice as thick as ATF at 40*C.
Mobil Super ATF+4 is 34.4cSt @ 40*C, Mobil 5W30 is 63.1 cSt @ 40*C. What happens when it's 0*F outside? No thanks.
These cases go several hundred thousand miles on old crummy Dexron. I've pulled quite a few apart, some higher mileage, for SYE installs and yolk seals. The guts having been run with ATF are always fine. Why reinvent the wheel (especially if you flat tow in the winter)?
Zaedock - As long as it's a light motor oil (no thicker than ATF when cold), the pump will be fine. IIRC, George at Transfer Cases Unlimited actually recommends 5w-30 synth engine oil. Putting in anything heavy, like gear oil, would be a bad idea.
Originally Posted By: Tempest
I would think that M1 10W30 High Mileage would be a very good choice for an ATF spec. T case.
Once again, the New Process / New Venture Jeep cases are NOT designed for motor oil. Use what the manufacturer specs. A 5W30 engine oil will be almost twice as thick as ATF at 40*C.
Mobil Super ATF+4 is 34.4cSt @ 40*C, Mobil 5W30 is 63.1 cSt @ 40*C. What happens when it's 0*F outside? No thanks.
These cases go several hundred thousand miles on old crummy Dexron. I've pulled quite a few apart, some higher mileage, for SYE installs and yolk seals. The guts having been run with ATF are always fine. Why reinvent the wheel (especially if you flat tow in the winter)?
Quote:
Mobil Super ATF+4 is 34.4cSt @ 40*C, Mobil 5W30 is 63.1 cSt @ 40*C. What happens when it's 0*F outside? No thanks.
What is the -40C specification limit for ATF+4?
Mobil Super ATF+4 is 34.4cSt @ 40*C, Mobil 5W30 is 63.1 cSt @ 40*C. What happens when it's 0*F outside? No thanks.
What is the -40C specification limit for ATF+4?
Never mind, I did the work for you:
http://www.imperialoil.ca/Canada-English/Files/Products_Lubes/IOCAENCVLMOMobil_Super_ATF_4.pdf
The Mobil product is 8800 cP @ -40C. Do you really think that 30 cSt is going to matter?
http://www.imperialoil.ca/Canada-English/Files/Products_Lubes/IOCAENCVLMOMobil_Super_ATF_4.pdf
The Mobil product is 8800 cP @ -40C. Do you really think that 30 cSt is going to matter?
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