Problems with swapping oil in a 923/925 transmission with synthetic?

[Baradium]

As I progress through actually winterizing my 923, I need to start seriously considering what to do about the oil in the transmission.

When it comes down to it, SAE30 or even 15W-40 is awfully thick at subzero temperatures. I already talked to cummins directly and was cleared on using 5W-40 rotella in the NHC-250 (I suspected it'd be fine but couldn't actually find anything saying so), so now I need to look at the transmission.

Ideally I'd prefer to go with the 5W-40 rotella in the transmission so I don't have to completely flush it and so there are fewer different fluid types in the truck. I also believe the rotella is also thinner than Dexron/Mercon in extreme cold. Does anyone have any input or knowledge on this? Or am I going to end up having to go to Allison?


It's also pretty common to put transmission pan heaters on vehicles up here (my F350 has a block heater, battery blankets [heaters], a battery maintainer, an oil pan heater, and a transmission pan heater), but with a 1500W electric block heater on the truck I don't have all that many amps left over after a block heater and battery maintainer to run more heat on a normal outlet. With that in mind, I definately think that something other than 15-40 or SAE 30 motor oil may be in order so it's just a matter of figuring out the course of action to take.

As it is I have time to think about it. I'm going to be putting a winch kit on the truck so I might as well wait to change fluids until after I get the PTO installed.

 

[dawico]

I have read a few times that Allison recommends ATF fluid and getting rid of the oil. I believe I recently read of a member that actually lost his low gears because of the thick oil and low temps. This was all read on this site BTW. Hopefully someone else can confirm this.

I am subscribed because I want to do what is best for my truck even though we don't see those low temperatures. I am not sure what is in it now, what fluid is the best, and what the best way to flush it would be.

 

[Doug Roberts]

Seen those big buckets of HD Tractor Transmission fluid in WalMart ? Check out the label , there ya go

 

[Csm Davis]

As I progress through actually winterizing my 923, I need to start seriously considering what to do about the oil in the transmission.

When it comes down to it, SAE30 or even 15W-40 is awfully thick at subzero temperatures. I already talked to cummins directly and was cleared on using 5W-40 rotella in the NHC-250 (I suspected it'd be fine but couldn't actually find anything saying so), so now I need to look at the transmission.

Ideally I'd prefer to go with the 5W-40 rotella in the transmission so I don't have to completely flush it and so there are fewer different fluid types in the truck. I also believe the rotella is also thinner than Dexron/Mercon in extreme cold. Does anyone have any input or knowledge on this? Or am I going to end up having to go to Allison?


It's also pretty common to put transmission pan heaters on vehicles up here (my F350 has a block heater, battery blankets [heaters], a battery maintainer, an oil pan heater, and a transmission pan heater), but with a 1500W electric block heater on the truck I don't have all that many amps left over after a block heater and battery maintainer to run more heat on a normal outlet. With that in mind, I definately think that something other than 15-40 or SAE 30 motor oil may be in order so it's just a matter of figuring out the course of action to take.

As it is I have time to think about it. I'm going to be putting a winch kit on the truck so I might as well wait to change fluids until after I get the PTO installed.

10wt is what is supposed to be in them according to the TM but for subzero temperatures it would be lighter than that I believe. Yeah just checked the TM says OEA 30 is good to -65, this is not regular 30wt.

 

[CARNAC]

I think a relook at the lubrication order is in order.

http://www.jatonkam35s.com/M939-5 tons/LO 9-2320-272-12.pdf

It specifies OE/HDO 10 for temps down to -15F. For temps below that as you have in AK, you are to use OEA (Lubricating Oil, Engine, Internal Combustion-Artic).

This is further stated in US Army Alaska regulation directing
http://www.usarak.army.mil/publications/PDF_Pubs/USARAK_Regulations/Regulation 750-4.pdf

Slide show on cold weather military maintenance ops
http://www.wainwright.army.mil/nwtc...her/Effects of Cold on Military Equipment.pdf

And when you're bored:
http://www.history.army.mil/html/books/104/104-23/CMH_Pub_104-23.pdf
http://www.history.army.mil/html/books/104/104-6/cmhPub_104-6.pdf

 

[Baradium]

So, unless someone knows what OEA-0W30 corresponds to, will 5W40 rotella suffice?

 

[patracy]

I can say from first hand experience, even two drain and fills will not get you to 100% on a oil swap.

 

[hklvette]

5W40... Rotella T6? If so I think that's a mineral oil based blend similar to other "synthetics". Of all the Rotella oils it should do the best when cold. What I would be looking for is the oil that has the proper weight when hot (SAE 10) and has the lowest pour point of all of the options.

 

[CARNAC]

OK let me be of further assistance.

This is a top secret fluid and I will assist you in finding some. First go to the top secret website spelled G then O then another O then a G then a L and finally an E. Then you can type in 0W30 and you'll be able to find it locally.


Sorry but you didn't just step on that landmine, you got on a pogo stick and started jumping up and down on top of that mine.


https://www.google.com/?gws_rd=ssl#q=0w30+oil

 

[Baradium]

OK let me be of further assistance.

This is a top secret fluid and I will assist you in finding some. First go to the top secret website spelled G then O then another O then a G then a L and finally an E. Then you can type in 0W30 and you'll be able to find it locally.


Sorry but you didn't just step on that landmine, you got on a pogo stick and started jumping up and down on top of that mine.


https://www.google.com/?gws_rd=ssl#q=0w30+oil

As far as I understand, not all oils are created equal. If you can find the actual SPECS on the mil oil I think it would help. The oil specified seems to be a diesel oil and I've never seen a 0W30 diesel oil availible normally. I'm not keen on taking risks with a different spec oil just because the viscosity is the same unless there's something else indicating that there won't be any harm. I just don't know if any of the diesel/HD specific properties might be needed.

EDIT:
I searched again and I do see now that the mobil 1 does say it meets the specs for some specific diesel engines. And it's only $10 a quart...

 

[Baradium]

5W40... Rotella T6? If so I think that's a mineral oil based blend similar to other "synthetics". Of all the Rotella oils it should do the best when cold. What I would be looking for is the oil that has the proper weight when hot (SAE 10) and has the lowest pour point of all of the options.

I'm also concerned with the oil specifications too. I just don't know what the transmission fully needs. It's easy enough to find the specified weight if I don't care about anything else with respect to the oil.

 

[Baradium]

So far I've found some oil that does meet the milspec. The first one that got back to me doesn't sell that oil anymore. Shell does make a diesel oil in 0W-30 that possibly could, but it also seems to be a Europe only oil and I'm not exactly fond of the idea of trying to ship 15 gallons of it (if it meets the spec). I'm waiting to hear back from a company in canada about their oil.

I haven't figured out if the mobil one diesel 0W-30 meets the milspec or not. It does appear to cost more a quart than Rotella T6 does a gallon. All the same I'm waiting to hear back from them as well.

Trying to get an answer from Allison about what I can use and what specs I actually need in the oil is getting me nowhere. It seems that their policy is I need to to ask a tech locally, so the tech can ask them if/when they don't know. I already know my local distributor doesn't have a tech because there aren't any in the state of Alaska, so I don't know exactly what that distributor does anymore, but there is someone listed that is technically one anyway. My next step is to try to get ahold of them during buisiness hours, which might take a while.


At this point, what I'm still trying to figure out is:

1) is 5W-40 rotella T6 an acceptable oil for this transmission, and if so, would it cover in temps down
to -40F, the truck realistically probably won't be operated down past -20F, so otherwise what the acceptable range would be.


2) if not, is there a severe detriment to running the military specified
0W-30 motor oil in place of ATF


3) If I am going to need to run the 0W-30 motor oil, can I use *any* 0W-30
motor oil, or does it need to meet that mil spec (or what oil can I use if it's not the milspec but something else)


4) Is the real answer that I need to take the risk of flushing the
transmission to ATF. There isn't an Allison transmission tech in the
entire state of Alaska, the companies that have fleets fly one in from WA as
needed (we had to get a transmission from WA for a fire truck because of
this). Knowing that, would a regular transmission shop even be able to do it?

 

[Scar59]

Seen those big buckets of HD Tractor Transmission fluid in WalMart ? Check out the label , there ya go

Ryan,
Don't over think the issue. 10w40 works great, 10w hyd fluid works great for the cold. Change the filter and look at the color of the fluid, most likely will still be clear/amber. More important is to ensure the tran vent is open and not obstructed.
Also, make sure the truck warms up after start up.
JC

 

[M35A2-AZ]

I do this also. But like Scar59 said, do not over think it.

 

[Csm Davis]

The standard 10wt is good down to -15 just use that. I want to know where everyone keeps getting to run 10w40 I have never seen it in or on the trucks or in the TM. If you are having problems I can put you in touch with folks in AK that can help you find a store to ask what everyone else up there runs.

 

[Nasty610]

A little searching on Google turned up this website: http://igor.chudov.com/manuals/M939...on-AT-MT-HT-Transmission-Operators-Manual.pdf
according to it a 0w20 oil is only good down to -22* F. That means Rotella T6 5w40 would not be a viable choice. I would suggest contacting an OTR/Medium duty truck repair shop in your area to see what they are running. Don't worry about the fluid meeting a Milspec. That is only used by the DoD for contracting purposes. I can tell you now that the when we replace fluid in the trucks in my unit we simply buy what the Manufacturer recommends not what the Military recommends.

 

[MtnSnow]

Best answer would be to call Allison's Transmission group and have them (they make the transmission in the truck) and use whatever they say to use.
Here is a Allison Distributor in AK..

Pacific Power Products Company
3177 North Van Horn Street Fairbanks, AK 99709
Phone: 907-479-1235
Fax: 907-479-1237

or
here is a Allison dealer

Trailercraft/Freightliner of Alaska
1301 E. 64th Avenue Anchorage, AK 99518
Phone: 907-563-3238
Fax: 907-562-6963

 

[lakeydna]

So far I've found some oil that does meet the milspec. The first one that got back to me doesn't sell that oil anymore. Shell does make a diesel oil in 0W-30 that possibly could, but it also seems to be a Europe only oil and I'm not exactly fond of the idea of trying to ship 15 gallons of it (if it meets the spec). I'm waiting to hear back from a company in canada about their oil.

I haven't figured out if the mobil one diesel 0W-30 meets the milspec or not. It does appear to cost more a quart than Rotella T6 does a gallon. All the same I'm waiting to hear back from them as well.

Trying to get an answer from Allison about what I can use and what specs I actually need in the oil is getting me nowhere. It seems that their policy is I need to to ask a tech locally, so the tech can ask them if/when they don't know. I already know my local distributor doesn't have a tech because there aren't any in the state of Alaska, so I don't know exactly what that distributor does anymore, but there is someone listed that is technically one anyway. My next step is to try to get ahold of them during buisiness hours, which might take a while.


At this point, what I'm still trying to figure out is:

1) is 5W-40 rotella T6 an acceptable oil for this transmission, and if so, would it cover in temps down
to -40F, the truck realistically probably won't be operated down past -20F, so otherwise what the acceptable range would be.


2) if not, is there a severe detriment to running the military specified
0W-30 motor oil in place of ATF


3) If I am going to need to run the 0W-30 motor oil, can I use *any* 0W-30
motor oil, or does it need to meet that mil spec (or what oil can I use if it's not the milspec but something else)


4) Is the real answer that I need to take the risk of flushing the
transmission to ATF. There isn't an Allison transmission tech in the
entire state of Alaska, the companies that have fleets fly one in from WA as
needed (we had to get a transmission from WA for a fire truck because of
this). Knowing that, would a regular transmission shop even be able to do it?

1 Rotella meets the allison C4 spec for the MT654CR transmission

2 I used to use Rotella T5 which was the 0W40, but I think it got replaced by the T6 5W40. I can't get 0W40 in rotella any more.

3 read the fine print it needs to say "Allison C4"

4 if you do call allison or wajax they'll probably tell you to use transynd, that's what they have on the shelf and is pricey.