Can you use a synthetic motor oil, say Mobil One 5-30 in the transfer case on a rebuild. If this is not recommended, then what is? I've also read 3 qts. through the speed sensor hole. How easy does this sensor come off? Any thing to look out for in this process? :spit:
LBZ: Synthetic lube for transfer case
- Thread starter Tank01
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I run 5w-30 in mine. It's quick and easy. Just make sure you have a pump to fill it. 3 is correct. Be careful with the speed sensor. It's plastic.
I did it on mine. I think I tweeked the sensor too much and it caused the Service brakes message and light and dinger to come on. I put a new sensor in Saturday. No issues yet. Drove it over 100 miles. snug it down finger tight then about 1/8 turn with a wrench.
The factory and recommended flll is ATF. The same ATF keeps the guts of your Allison alive for 100's of thousands of miles, so why do you feel the need to run a non-approved fluid in the t-case?
Keep in mind that in the unlikely event the front seal in the t-case should leak and it's fluid ends up in the transmission, you will now be adding motor oil to your transmission's ATF. Just something to consider.
Keep in mind that in the unlikely event the front seal in the t-case should leak and it's fluid ends up in the transmission, you will now be adding motor oil to your transmission's ATF. Just something to consider.
One of the sharpest minds on the Allison suggests that it's alright running engine oil in the transfer case. I'll take his word for it that it'll be ok in doing so. Mines got 3 qts in it & no issues in the 15k+ miles it's been in there.
I don't see a flaw in your reasoning either though. Sure won't hurt to just use 2qts ATF like it calls for I don't imagine.
I don't see a flaw in your reasoning either though. Sure won't hurt to just use 2qts ATF like it calls for I don't imagine.
Merchant recommended a Amsoil Syn Hyd oil that he carries. Said he saw the temp drop in using it. I've never had a problem with running syn ATF.
Factory fluid is atf on the 3/4 diesel. Auto trac is used in the auto 4wd t-cases with clutches.
Here is a little bit of info:
http://www.duramaxdiesels.com/forum/showthread.php?t=2468&highlight=transfer+case
I have been running syn 5w30 in my T case for over 2 years now.
http://www.duramaxdiesels.com/forum/showthread.php?t=2468&highlight=transfer+case
I have been running syn 5w30 in my T case for over 2 years now.
I asked the man (Mike L.) directly about this issue. Below is what he said:
"I never recommended the 5/30 synthetic oil. I posted the test results and why the problem exists.
The big problem is; no one ever checks their fluid in the T/C. The T/C runs so hot that the atf vaporizes. The idea behind the synthetic engine oil is for people that do not check their T/C fluid at every oil change. It lasts longer and tends not to evaporate as quickly. Doest it lubricate better? Yes, but it does not address the rubber parts in the case.
My suggestion is to check the level at every other engine oil change and do NOT depend on the monkey doing it. ATF is absolutely fine for lube."
And if I remember correctly he also said if you do decide to use the 5W-30 oil to change the oil every 10K miles.
Mike L. please correct me if I am wrong!
"I never recommended the 5/30 synthetic oil. I posted the test results and why the problem exists.
The big problem is; no one ever checks their fluid in the T/C. The T/C runs so hot that the atf vaporizes. The idea behind the synthetic engine oil is for people that do not check their T/C fluid at every oil change. It lasts longer and tends not to evaporate as quickly. Doest it lubricate better? Yes, but it does not address the rubber parts in the case.
My suggestion is to check the level at every other engine oil change and do NOT depend on the monkey doing it. ATF is absolutely fine for lube."
And if I remember correctly he also said if you do decide to use the 5W-30 oil to change the oil every 10K miles.
Mike L. please correct me if I am wrong!
I have run mineral oil based Dex III in my 241 case for 50k miles, and the oil level NEVER dropped, so I dispute the "evaporation" claim. Note that this case is very similar internally to the 261/263 cases, and my use included long stretched of high speed highway driving, lots of in town (were talking AZ heat here), and a LOT of wheeling. And by wheeling, I don't mean puttering down dirt roads in 4WD, I mean actual wheeling:
Now, granted, this truck has manual hubs, so when I'm not offroad neither the front driveshaft nor chain is turning, but I can't imagine there is much difference in heat generation. T-cases don't get very hot anyway, even after long stretches of highway travel or extensive off roading. Any oil loss I have ever seen from any t-case has always been due to leakage, which is why you should check it every oil change.
I guess my point is, the case was designed and spec'd to use ATF, so why use anything else? If you want a better lube in it, use a synthetic ATF, whether it is Transynd or some other brand. At least that way you know there are no compatibility issues between the fluid and the seals, nor with the trans fluid and t-case fluid should accidental mixing occur.
That's just my loose change on the subject. Transfer cases are NOT very demanding from a lubrication standpoint. No sense overthinking it.
Now, granted, this truck has manual hubs, so when I'm not offroad neither the front driveshaft nor chain is turning, but I can't imagine there is much difference in heat generation. T-cases don't get very hot anyway, even after long stretches of highway travel or extensive off roading. Any oil loss I have ever seen from any t-case has always been due to leakage, which is why you should check it every oil change.
I guess my point is, the case was designed and spec'd to use ATF, so why use anything else? If you want a better lube in it, use a synthetic ATF, whether it is Transynd or some other brand. At least that way you know there are no compatibility issues between the fluid and the seals, nor with the trans fluid and t-case fluid should accidental mixing occur.
That's just my loose change on the subject. Transfer cases are NOT very demanding from a lubrication standpoint. No sense overthinking it.
because our tcases wernt designed to be launched in 4wd, and there are better fluids for the tcase heat.
I have almost 50k on my tcase with 5-30 and it's seen it's fair share of "heat"
i cant see it being very likely that a leaky t-case seal could allow enough oil to enter through to the tranny. not only is the tcase "sump" lower than the output shaft, but tranny tilts back too. the oil would have to overcome some serious force to ever touch a clutch surface, I think. I could be minimizing it, but im not worried one bit.
Does anyone else lose oil out of the rear seal? Mine leaks onto the shaft and gets slung all under the body. It has done it since it was new but when I check the level its always where it should be or just slightly low. When I pull the trans I'll replace the seal just for good measure.
I changed mine out a couple of months ago. $80 at the dealer for the seal. That was the only place that had it locally. I rented the 3 jaw slide hammer from Advance Auto. removed it on the second hit. :thumb:
261/263's have oil pumps in them that feed oil through the mainshaft to the front bearings. So, there is plenty of oil on that seal.
Im not saying it will happen or even could happen, but it is one more reason to run the same lube in the t-case as the trans. JMHO.
Mine isn't an auto 4wd unit but it came from the factory with that lubricant and the VIN lookup still list it as the specified oil for use. Maybe Chevy doesn't know what they are talking about. The transfer case still has a clutch type material that allows for shifting into 4wd that acts like a brake to slow the speed of the two rotating pieces so that the splines will engage and slide over each other.
I have run mineral oil based Dex III in my 241 case for 50k miles, and the oil level NEVER dropped, so I dispute the "evaporation" claim. Note that this case is very similar internally to the 261/263 cases, and my use included long stretched of high speed highway driving, lots of in town (were talking AZ heat here), and a LOT of wheeling. And by wheeling, I don't mean puttering down dirt roads in 4WD, I mean actual wheeling:
Now, granted, this truck has manual hubs, so when I'm not offroad neither the front driveshaft nor chain is turning, but I can't imagine there is much difference in heat generation. T-cases don't get very hot anyway, even after long stretches of highway travel or extensive off roading. Any oil loss I have ever seen from any t-case has always been due to leakage, which is why you should check it every oil change.
I guess my point is, the case was designed and spec'd to use ATF, so why use anything else? If you want a better lube in it, use a synthetic ATF, whether it is Transynd or some other brand. At least that way you know there are no compatibility issues between the fluid and the seals, nor with the trans fluid and t-case fluid should accidental mixing occur.
That's just my loose change on the subject. Transfer cases are NOT very demanding from a lubrication standpoint. No sense overthinking it.
So you post up a picture of a truck that does not use this transfer case and you in particular have not seen this problem with your transfer case and call b/s? Tell me how much study you have done on this.
How many T/C's have you looked at in the Duramax? What do you do for a living besides diagnosing these trucks on the internet? Have you actualy seen more than one tranfer case. from the outside?
I just love exSperts.