Atlas 2-speed questions
07-01-2017, 02:10 PM
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Atlas 2-speed questions
I'm Looking for help from Atlas t-case owners. I have a relatively new install of an Atlas 2 3.0:1 t-case behind an ls3/6l80. I changed out the rear cv to a flange style to match my Adams driveshaft.
Today I was on my way to go wheeling when I started to smell gear oil. I decided to stop and check it out, and I'm glad I did. It was slinging oil all over the under side of the jeep. When I began to inspect it, the t-case was VERY hot.... so hot I couldn't touch it. I couldn't even get my hand close to the brass breather to check to see if the hose was still connected.
After I got it home, and let it cool for several hours, I wiped it down and found that it was leaking at the rear seal.
I am a few miles shy of the 5000 mile maintenance. My questions are-
Is it normal for the Atlas to be that hot? I've never checked it out right after driving 130+ miles.
I will pull the driveshaft and check the flange washer and nut, but is it possible that heat caused the seal failure? Or caused the rtv to leak oil past the washer?
Thanks in advance for your insight!
-Chris
Today I was on my way to go wheeling when I started to smell gear oil. I decided to stop and check it out, and I'm glad I did. It was slinging oil all over the under side of the jeep. When I began to inspect it, the t-case was VERY hot.... so hot I couldn't touch it. I couldn't even get my hand close to the brass breather to check to see if the hose was still connected.
After I got it home, and let it cool for several hours, I wiped it down and found that it was leaking at the rear seal.
I am a few miles shy of the 5000 mile maintenance. My questions are-
Is it normal for the Atlas to be that hot? I've never checked it out right after driving 130+ miles.
I will pull the driveshaft and check the flange washer and nut, but is it possible that heat caused the seal failure? Or caused the rtv to leak oil past the washer?
Thanks in advance for your insight!
-Chris
07-01-2017, 03:10 PM
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Did you change the seal when you went to the flange? Sometimes there is a difference in diameter of a yolk and a flange. How close is your exhaust to the transfer case?
07-01-2017, 03:28 PM
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The exhaust... the passenger side crosses over under the flange. It's close-ish... maybe 6" on driver, passenger, and tail end.
The issue right now is that I have damaged one of the hex bolts on my skid plates. Tomorrow, I'll drill it out and get an eye on the flange and flange nut.
07-02-2017, 12:29 PM
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Ok, I finally got my skid plate off and was able to get on the t-case.
The exhaust is closer than I indicated. It's about 2" at its closest point on the driver and passenger side. In my inspection, I also found the electronics for the atlas got hot enough to deform the box. It was zip tied to the transmission tcm harness which is near the exhaust. It appears that I need to find a new home for that before I run the jeep again.
The flange nut was tight. I checked with torque wrench at 150 ft/lbs.
The gear oil seemed to be what I expected from a new atlas being broke in. The fluid was not burn, smelled like gear oil, and I did not find any big metal in the fluid. The magnet was about twice its diameter with metal but, again, didn't seem unusual for a tcase going through a break-in period.
More on the heat- I do have evidence that the tcase got hot enough to make the plastic wire loom deform. I had the lines that run to the shifter position sensors run above the tcase to the Atlas breakout box thing. I have seen posts that an atlas, especially a new one, can run hot and push oil out the breather. My breather is run up the bell housing and zip tied to the firewall. AA recommends at least 3' of 3/8 hose. Mine is probably close to 5' with a breather vent on top. It did not puke any fluid out of the breather, for what it's worth.
I'm wondering if the fluid was foaming and that allowed it to leak past the flange seal? Or, maybe the seal is bad or installed incorrectly?
Beyond that, I don't know where to go from here. Any thoughts?
-Chris
The exhaust is closer than I indicated. It's about 2" at its closest point on the driver and passenger side. In my inspection, I also found the electronics for the atlas got hot enough to deform the box. It was zip tied to the transmission tcm harness which is near the exhaust. It appears that I need to find a new home for that before I run the jeep again.
The flange nut was tight. I checked with torque wrench at 150 ft/lbs.
The gear oil seemed to be what I expected from a new atlas being broke in. The fluid was not burn, smelled like gear oil, and I did not find any big metal in the fluid. The magnet was about twice its diameter with metal but, again, didn't seem unusual for a tcase going through a break-in period.
More on the heat- I do have evidence that the tcase got hot enough to make the plastic wire loom deform. I had the lines that run to the shifter position sensors run above the tcase to the Atlas breakout box thing. I have seen posts that an atlas, especially a new one, can run hot and push oil out the breather. My breather is run up the bell housing and zip tied to the firewall. AA recommends at least 3' of 3/8 hose. Mine is probably close to 5' with a breather vent on top. It did not puke any fluid out of the breather, for what it's worth.
I'm wondering if the fluid was foaming and that allowed it to leak past the flange seal? Or, maybe the seal is bad or installed incorrectly?
Beyond that, I don't know where to go from here. Any thoughts?
-Chris
07-02-2017, 06:10 PM
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07-03-2017, 09:20 PM
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You might want to give Steve a call over at Advance Adapters. Unlike the JK's 241 transfer case which uses straight roller bearings on the front output shaft the Atlas 2 uses tapered roller bearings.
The Atlas is also gear-driven and uses heavy gear lubricant, what this means is more friction than the chain driven 241 running ATF. Many moons ago when our Jeeps weighed 3,500 lb and had less than 200 horsepower there wasn't much stress on the transfer case. Our modern JK's without unlocking hubs weighing in excess of 5,000 pounds and traveling at speeds of 80 miles an hour have put a heavy load on the transfer case. Traveling at high speeds with the front axle driving the countershaft means even shallow turns can it cause a wide speed differential between the gear sets in the transfer case.
Running tapered rollers mean end play is critical. Unlike the spindle on a car which is forged from steel heat cycles do not change the tolerances by much but in the larger Atlas transfer it can. The aluminum case can grow in excess of 7 thousands so end play is kept pretty tight. We have installed dozens of Atlas's and in a couple cases we have found the end play on the counter shaft too tight, it's really not a problem unless running a heavy JK especially on the highway without unlocking front hubs. A while back there were some cases machined differently that had this issue and Advance is aware of it. It's a pretty simple fix basically removing a shim behind the rear cover.
But it would be best to call Steve over at Advance he is very knowledgeable and aware of Atlas's that run hot. Recently Advance cut the floor out of a JK and did thermal testing to address these exact issues, a 7,000 lb JK running 80 miles an hour in the mountains of Colorado, V8 JK's have changed the game.
Once set up properly the Atlas 2 is very strong and we run them with our swap with little issue.
The Atlas is also gear-driven and uses heavy gear lubricant, what this means is more friction than the chain driven 241 running ATF. Many moons ago when our Jeeps weighed 3,500 lb and had less than 200 horsepower there wasn't much stress on the transfer case. Our modern JK's without unlocking hubs weighing in excess of 5,000 pounds and traveling at speeds of 80 miles an hour have put a heavy load on the transfer case. Traveling at high speeds with the front axle driving the countershaft means even shallow turns can it cause a wide speed differential between the gear sets in the transfer case.
Running tapered rollers mean end play is critical. Unlike the spindle on a car which is forged from steel heat cycles do not change the tolerances by much but in the larger Atlas transfer it can. The aluminum case can grow in excess of 7 thousands so end play is kept pretty tight. We have installed dozens of Atlas's and in a couple cases we have found the end play on the counter shaft too tight, it's really not a problem unless running a heavy JK especially on the highway without unlocking front hubs. A while back there were some cases machined differently that had this issue and Advance is aware of it. It's a pretty simple fix basically removing a shim behind the rear cover.
But it would be best to call Steve over at Advance he is very knowledgeable and aware of Atlas's that run hot. Recently Advance cut the floor out of a JK and did thermal testing to address these exact issues, a 7,000 lb JK running 80 miles an hour in the mountains of Colorado, V8 JK's have changed the game.
Once set up properly the Atlas 2 is very strong and we run them with our swap with little issue.
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07-04-2017, 01:51 PM
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Thanks for the insight, Robbie. They were closed yesterday and of course today, so I'll give Steve a call tomorrow. I'll post up with his suggestions.
-Chris
-Chris
07-06-2017, 05:45 AM
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I spoke with Scott at AA. Steve is on vacation. He said it is not unusual for the Atlas to run very hot. Since there was no excessive play or wiggle, his recommendation was to replace the seal and reinstall the flange. 2 day amazon prime delay on the seal since no one carries it locally.
I also found out that AA is now shipping the atlas with Redline MT-90. The documentation in the knowledge base has one doc that says Redline and another doc that still says Amsoil with the 3 alternatives should you not be able to get the amsoil. Scott said any of them still work, but they are now shipping with Redline. Hope this saves someone some confusion on what to put in it.
I'm waiting on the seal to arrive, hopefully tomorrow. Once it's back together, I'll get it on a test drive and see if it keeps its fluid inside. I'm also going to put the temp probe on my meter and get a temp measurement. AA documentation says 250 is max operating temperature but I've never seen anyone say what their real world temp is exactly.
-Chris
I also found out that AA is now shipping the atlas with Redline MT-90. The documentation in the knowledge base has one doc that says Redline and another doc that still says Amsoil with the 3 alternatives should you not be able to get the amsoil. Scott said any of them still work, but they are now shipping with Redline. Hope this saves someone some confusion on what to put in it.
I'm waiting on the seal to arrive, hopefully tomorrow. Once it's back together, I'll get it on a test drive and see if it keeps its fluid inside. I'm also going to put the temp probe on my meter and get a temp measurement. AA documentation says 250 is max operating temperature but I've never seen anyone say what their real world temp is exactly.
-Chris
