dnewton3
Staff member
Allow me to shed some light here, because I've gone DEEP into this topic on another website.
First, we need to be specific about which transfer case we're speaking of, and then make sure we understand all the different fluids GM has used in certain applications.
There is an "Auto Trak" t-case system that is an automated 4x4 system; it is common in the SUV and light-duty truck applications. It will automatically switch to 4x4 mode by monitoring the ABS sensors, etc. The PCM will decide when to switch into 4x4 for you, if you're in "auto" mode. You can over-ride this and go into full time 4wd by manually switching into it. This is NOT the same type system as what I'll next discuss.
There is an electronically shifted 4x4 system, where you run in 2WD at all times, until the driver decides to shift into 4x4 mode, by pushing a button. All this does is cause an electronic solenoid to shift the t-case as well as move a locking collar on the CAD (center axle disconnect) on the front axle. This type system can be found on light duty trucks and the 2500HD and 3500HD trucks.
Finally, there is an ol-skool system where there is a manual shift lever on the floor. Same options as the former above, but you manually shift the t-case. There is also still an electronic solenoid that shifts the locking collar on the CAD, though.
Now that you understand those options, then we can now discuss fluids.
GM has an "AutoTrak" fluid. It is essentially an ATF with a whole lot of AW stuff in it. It was spec'd for the AutoTrak systems. It's uber expensive (as most OEM fluids are) and it's a good idea to use for the AutoTrak systems because they have a unique approach to the 4x4 automated switching mode. But it's completely unneccessary for the "traditional" 4x4 t-cases.
GM used to have the DEX III fluid; we're all familiar with that. For many, many years, that was the fluid put into the NV 261 (manual shift) and 263 (electronic shift) HD t-cases. That is the fluid that was in mind when NV designed the t-case with GM. It works just fine in that application. When GM quit the DEX III licensing, they had not gone through all the way and proven the "new" DEX VI into all apps. They only focused on auto trannies at first. And so there were applications where former DEX III fluids were left wanting. So GM took the former DEX III fluid and renamed it "Manual Transmission and Transfer Case Fluid". Yes - they actually took the exact same spec for the former DEX III and simply renamed it to an application specific to manual trannies and t-cases. Same specs, same color, etc. Here is a picture of it that I bought and posted online for proof:
http://www.dieselplace.com/forum/attachm...se-dsc02205.jpg
Here is a quote from GM at the time; it may not be relevant today, though:
"This information applies to 2007 and prior GM passenger cars and trucks.
Dexron III is being phased out as a product name. It is being renamed Manual Transmission Fluid and carries p/n 88861800 US (88861801 Canada). If fluid p/n 88861800 US (88861801 Canada) is not yet availble when servicing a manual transmission or transfer case, Dexron III can be used in its place.
DO NOTE used Dexron VI i nplace of manual tranmission fluid in any manual transmissions or transfer cases that specify Dexron III, as a failure may result."
For those of you who simply MUST HAVE a GM DEX III fluid, then you can buy this stuff and it is exactly the same, but under a new name and part number. Last time I checked, it was still available.
Only later, when they did a redesign of the t-case with the new body style in 2008, did they switch to the DEX VI fluid in the t-cases as an approved fluid.
Additionally, GM also has a manual tranny fluid that is a darker fluid, intended for other synchromesh applications. It is gear oil type fluid, and not to be confused with the red ATF based fluid I mentioned above.
My point is that GM has used many different fluids, in many different applications, and GM is known for (at best being described as) misleading and confusing statements when it comes to fluids, to be blunt.
So, for the OP, if you have a 263 t-case that called for the former DEX III, then your selection of the MaxLife is a perfect solution. Any fluid that would be targeted for the former Dex III/Mercon type fluid applications, will benefit from such continued use.
******* SIDE TOPIC of INTEREST:
I will make a side note here, because there is much contention on some other sites about the topic I'll next discuss ...
There is an article in a trade magazine where Mike Weinberg from Rockland Standard Gear makes mention of ditching the ATF and using a 5w-30 motor oil in the aforementioned t-cases. His entire thought is that ATF is "too thin" and "evaporates" from the t-case. I know this because I personally emailed him several years ago about this very topic, and had a detailed email conversation. I also did exhaustive research on the topic, and it is my conclusion that his recommendation is based upon old school thinking. When I challendged him on any meaningful criteria (vis ranges, AW properties, maintenance criteria) he offered no credible answer that would lead me to believe he put any real research into the topic. Simply put, he SWAG'd it.
To be fair, I also contacted engineers at NV, and one at Jasper reman (very well respected reman entity in IN). I also contacted the reman industry leaders. Of all of them, every single one EXCEPT Weinberg, said that using OEM spec fluids was the right approach. And no entity would back up their warranty unless you used correct OEM spec'd fluids.
Now, I'm not saying that motor oil will destroy the t-case; there is no proof of that. But there is also zero proof that motor oil is "better" in those applications he refers to.
Mike's premise was that, as a reman source, they see a lot of t-cases come in with no fluid. He blamed the ATF. However, I would contend that is not a fault of the ATF, but a fault of poor maintenance on the part of the vehicle owners. Why blame ATF for a fluid level at zero? Would you blame the motor oil if your crankcase were dry, too? Is it the fault of the GL-5 when your diff grinds to a powder for a lack of lube? His assertion of using motor oil is based upon a false premise; that ATF is unfit for use in the t-case. I contend that if your t-case fluid level it low, it's YOUR fault, and not that of the fluid. As much as folks are often overly anal about their engine oil, many simply neglect the other driveline components when it comes to fluid level checks. While that many not be true of BITOGers, it most certainly is true of the general public.
As most of us know, many synthetic fluids will often resist evaporation moreso than lesser fluids. If Mike believed that ATF was an issue, then why not recommend syn ATF? That way, you'd have a properly spec'd fluid, with higher temp NOACK properties, all for the right application. But instead, he simply went ol-skool and thought "motor oil must be thicker, so it must be better." Nothing could be further from the truth.
First, we need to be specific about which transfer case we're speaking of, and then make sure we understand all the different fluids GM has used in certain applications.
There is an "Auto Trak" t-case system that is an automated 4x4 system; it is common in the SUV and light-duty truck applications. It will automatically switch to 4x4 mode by monitoring the ABS sensors, etc. The PCM will decide when to switch into 4x4 for you, if you're in "auto" mode. You can over-ride this and go into full time 4wd by manually switching into it. This is NOT the same type system as what I'll next discuss.
There is an electronically shifted 4x4 system, where you run in 2WD at all times, until the driver decides to shift into 4x4 mode, by pushing a button. All this does is cause an electronic solenoid to shift the t-case as well as move a locking collar on the CAD (center axle disconnect) on the front axle. This type system can be found on light duty trucks and the 2500HD and 3500HD trucks.
Finally, there is an ol-skool system where there is a manual shift lever on the floor. Same options as the former above, but you manually shift the t-case. There is also still an electronic solenoid that shifts the locking collar on the CAD, though.
Now that you understand those options, then we can now discuss fluids.
GM has an "AutoTrak" fluid. It is essentially an ATF with a whole lot of AW stuff in it. It was spec'd for the AutoTrak systems. It's uber expensive (as most OEM fluids are) and it's a good idea to use for the AutoTrak systems because they have a unique approach to the 4x4 automated switching mode. But it's completely unneccessary for the "traditional" 4x4 t-cases.
GM used to have the DEX III fluid; we're all familiar with that. For many, many years, that was the fluid put into the NV 261 (manual shift) and 263 (electronic shift) HD t-cases. That is the fluid that was in mind when NV designed the t-case with GM. It works just fine in that application. When GM quit the DEX III licensing, they had not gone through all the way and proven the "new" DEX VI into all apps. They only focused on auto trannies at first. And so there were applications where former DEX III fluids were left wanting. So GM took the former DEX III fluid and renamed it "Manual Transmission and Transfer Case Fluid". Yes - they actually took the exact same spec for the former DEX III and simply renamed it to an application specific to manual trannies and t-cases. Same specs, same color, etc. Here is a picture of it that I bought and posted online for proof:
http://www.dieselplace.com/forum/attachm...se-dsc02205.jpg
Here is a quote from GM at the time; it may not be relevant today, though:
"This information applies to 2007 and prior GM passenger cars and trucks.
Dexron III is being phased out as a product name. It is being renamed Manual Transmission Fluid and carries p/n 88861800 US (88861801 Canada). If fluid p/n 88861800 US (88861801 Canada) is not yet availble when servicing a manual transmission or transfer case, Dexron III can be used in its place.
DO NOTE used Dexron VI i nplace of manual tranmission fluid in any manual transmissions or transfer cases that specify Dexron III, as a failure may result."
For those of you who simply MUST HAVE a GM DEX III fluid, then you can buy this stuff and it is exactly the same, but under a new name and part number. Last time I checked, it was still available.
Only later, when they did a redesign of the t-case with the new body style in 2008, did they switch to the DEX VI fluid in the t-cases as an approved fluid.
Additionally, GM also has a manual tranny fluid that is a darker fluid, intended for other synchromesh applications. It is gear oil type fluid, and not to be confused with the red ATF based fluid I mentioned above.
My point is that GM has used many different fluids, in many different applications, and GM is known for (at best being described as) misleading and confusing statements when it comes to fluids, to be blunt.
So, for the OP, if you have a 263 t-case that called for the former DEX III, then your selection of the MaxLife is a perfect solution. Any fluid that would be targeted for the former Dex III/Mercon type fluid applications, will benefit from such continued use.
******* SIDE TOPIC of INTEREST:
I will make a side note here, because there is much contention on some other sites about the topic I'll next discuss ...
There is an article in a trade magazine where Mike Weinberg from Rockland Standard Gear makes mention of ditching the ATF and using a 5w-30 motor oil in the aforementioned t-cases. His entire thought is that ATF is "too thin" and "evaporates" from the t-case. I know this because I personally emailed him several years ago about this very topic, and had a detailed email conversation. I also did exhaustive research on the topic, and it is my conclusion that his recommendation is based upon old school thinking. When I challendged him on any meaningful criteria (vis ranges, AW properties, maintenance criteria) he offered no credible answer that would lead me to believe he put any real research into the topic. Simply put, he SWAG'd it.
To be fair, I also contacted engineers at NV, and one at Jasper reman (very well respected reman entity in IN). I also contacted the reman industry leaders. Of all of them, every single one EXCEPT Weinberg, said that using OEM spec fluids was the right approach. And no entity would back up their warranty unless you used correct OEM spec'd fluids.
Now, I'm not saying that motor oil will destroy the t-case; there is no proof of that. But there is also zero proof that motor oil is "better" in those applications he refers to.
Mike's premise was that, as a reman source, they see a lot of t-cases come in with no fluid. He blamed the ATF. However, I would contend that is not a fault of the ATF, but a fault of poor maintenance on the part of the vehicle owners. Why blame ATF for a fluid level at zero? Would you blame the motor oil if your crankcase were dry, too? Is it the fault of the GL-5 when your diff grinds to a powder for a lack of lube? His assertion of using motor oil is based upon a false premise; that ATF is unfit for use in the t-case. I contend that if your t-case fluid level it low, it's YOUR fault, and not that of the fluid. As much as folks are often overly anal about their engine oil, many simply neglect the other driveline components when it comes to fluid level checks. While that many not be true of BITOGers, it most certainly is true of the general public.
As most of us know, many synthetic fluids will often resist evaporation moreso than lesser fluids. If Mike believed that ATF was an issue, then why not recommend syn ATF? That way, you'd have a properly spec'd fluid, with higher temp NOACK properties, all for the right application. But instead, he simply went ol-skool and thought "motor oil must be thicker, so it must be better." Nothing could be further from the truth.
