Converting a 923 over from motor oil in the Allison to transmission fluid.

[MuleMac01]

Yeah change to 10wt

You think that will help it auto SHIFT without letting off the throttle?

 

[MuleMac01]

Ok I will drain out the new dex 3 and put it into a bucket and buy the napa stuff 10wt oil I will let you know if that changes anything....

 

[Coffey1]

I have 10 w in my 1984 M923
Andy who lives near me has 15/40 in his 1984 M923
Allison if I read it right says dex is for hwy use
10 w is for off road use and heavy load use.
So in my opinion if 10w is for extreme heavy use it should be good for hwy use.

 

[trooper632]

I took back the Dex III yesterday and changed it out for NAPA 10w Hyd oil, which says on the bucket that is compatible for Allison C-4, Gonging to change both filters and see how it works. Not having any issuses at all right now shifts good and smooth but wanted to change it out before I start using it during these Texas summers.

 

[TXFirefighter]

Here is the link to the Allison Approved fluids page.
On Highway are ALL ATF fluids, Off Highway have a mix of oils.

http://www.allisontransmission.com/parts-service/approved-fluids/on-highway-fluids

 

[Csm Davis]

Mulemac it might but it may also involve adjustment of the cable that goes to the throttle.

 

[Csm Davis]

Those Military Guys I don't think down here in the southern part of the USA it will get cold enough to be a problem but those fellers up north could have bad problems in the cold.

 

[Mike929]

Here is the link to the Allison Approved fluids page.
On Highway are ALL ATF fluids, Off Highway have a mix of oils.

http://www.allisontransmission.com/parts-service/approved-fluids/on-highway-fluids

Thanks for the link, sure wish Allison would have been more specific as to what to use.

So what do you think the difference is between on road and off road? lower speeds and higher heats off road, vs. higher speeds and less heat on highway.

Sure wish they listed good, better, best for MT654CR transmission, or would even say which group of fluids are recommended for the MT654CR.

(I am assuming that the M939 series trucks use the MT654CR per the inter-webs)

 

[TXFirefighter]

Thanks for the link, sure wish Allison would have been more specific as to what to use.

So what do you think the difference is between on road and off road? lower speeds and higher heats off road, vs. higher speeds and less heat on highway.

Sure wish they listed good, better, best for MT654CR transmission, or would even say which group of fluids are recommended for the MT654CR.

(I am assuming that the M939 series trucks use the MT654CR per the inter-webs)

I really can't speak to the M-series trucks but in the fire service I think we classify as Severe Duty! A typical ladder truck with a pump on it weighs in around 78K lbs with all it's equipment and hose. We go from cold in the station to full throttle in 90 to 120 seconds from start up. In the older trucks with the HD740 transmissions we ran Dextron. Serviced filters once a year and changed the oil every other year. When we changed to the transynd, we extended our drain interval to 5 years but still kept the filter change at once a year. It was also worth a 15 degree drop in operating temp.
The newer trucks with the 4000 series transmissions are ALL coming filled with transynd from the factory.

I have seen machinery with Allisons that had engine oil in them but as far as trucks, everything I have dealt with has been filled with some type of ATF.

Oh, Just a note, Amsoil may claim to meet the TES 295 spec but they have not submitted their oil to testing for official Allison approval. Due to that fact, I do not use that product in any of the fire trucks I service. Just can't take the liability.

 

[acme66]

It might be worth noting that Dex III is a 10w oil.

Some of you might be running in hotter climates than I am, that might explain some of the things you describe. Others well, I think some have made up their minds one way or the other and it isn't going to change regardless. I can say that we have about 400 miles on the change now with about 50 of those in low range grinding up and down some very steep hills. The smooth shifting is still very awesome but on the tour runs somewhat diluted by being in low range. I get some bucking coming down the trail as the converter locks/unlocks and or the trany shifts. Sometimes I think the Allison gets confused. I can combat this by keeping her in high range until the very last moment but on the down hill leaving it in high means lots of riding the brakes. My 2 to 1 is still smooth as butter and I still have the exact same temp drop of 20. Grinding the last 3 miles up it will climb to 205, cool off to 195 at the top and climb back to 205 on the return.

Again do what you want, I am simply sharing what I am doing. I am using the truck much, much, much harder than parade duty but much less than the military during deployment. There seems to be some confusion about what dex III is or isn't. It is a 10w oil with additives for the auto tranny. To say dex is to thin and you are going to run a 10w motor oil is like saying you don't like pink so you are using fuschia. I bet 10w is to thin for some of you down south, it isn't up here. That said I didn't use dex III, I used that heavy equipment hydraulic and transmission fluid with the C4 rating. It is working awesome and I will continue to update and you can see how we did at the end summer. I am putting 20+ people in the back and climbing 4000 feet in about 4 miles. Trust me that transmission is stretching her legs. If I come off the mountain at the end of the season with more 500 miles in low range under my belt and the Alison is still snug and happy will you all please drop the running 10w transmission fluid will kill it but 10w motor oil will save it thing. 10w is 10w, that is what the 'w' means. (ok I think dex III is really a 9w but c'on)

Wait and see how it works for me if you are at all on the fence, I will let you know one way or the other by September.

Ken

PS: Come and visit us in Nevada City Montana and take a ride. It is one heck of a trip, 14 miles, about 6 of which will feel like they are straight up. 8500 feet in elevation right to the foot of a mountain and through more than a dozen mines and 5 old towns. I can no longer offer camping at our place because the 923 is parked there but I can recommend both with and without services. (read paid or free) Mention SS and I will discount the whole group 50%.

 

[Those Military Guys]

Csm Davis true so if you live where it gets really cold i would go with the 10wt in the trans

 

[brock]

[PS: Come and visit us in Nevada City Montana and take a ride. It is one heck of a trip, 14 miles, about 6 of which will feel like they are straight up. 8500 feet in elevation right to the foot of a mountain and through more than a dozen mines and 5 old towns. I can no longer offer camping at our place because the 923 is parked there but I can recommend both with and without services. (read paid or free) Mention SS and I will discount the whole group 50%.[/QUOTE]

You got a website for your tours?

 

[patracy]

I did a drain and fill on mine. (M931) I didn't use Dex III, but rather "generic top off fluid". It's basically a universal ATF fluid for lubrication without the special additive packs. Shifting improved on my truck with no negative impacts. I just drained the pan and replaced the spin on filter in mine. So there's still a good bit of motor oil in the transmission.

 

[plode]

I'm going to change mine this week, as the pan gasket is leaking really bad. I'm looking hydraulic oils at Tractor supply. Trying to figure out which one I want to buy.
I want to check to ensure the vent isn't clogged...is there any easy way to get to it? It appears the vent line runs to the top of the transmission, almost in an impossible to get to location.
I fired the truck up today, moved it 20 feet so I could mow the grass where it gets parked, let it idle, and in the two minutes or so it took me to run the lawn tractor, the truck left a 8" puddle of oil on my driveway, from the transmission. It appears to be from the pan gasket.

 

[Coffey1]

Been doing some more research and everyone running dex should be fine as long as your not doing extreme off roading or heavy hauling or doing both off rd heavy hauling.
This would not include pulling trailers.
The reason from what I am unstanding is dex has a lower boiling point and will over heat.

 

[Mike929]

Been doing some more research and everyone running dex should be fine as long as your not doing extreme off roading or heavy hauling or doing both off rd heavy hauling.
This would not include pulling trailers.
The reason from what I am unstanding is dex has a lower boiling point and will over heat.

That supports the TM which shows dex for 75+ temps and the oil solution for 100+ temps. That was one reason for my interest in this thread. Is the synthetic best of both worlds or just an expensive version of dex.

I will be driving in 100+ temps but unlikely to be fully loaded or extreme off road. My thought is if I have what is needed for loaded and off road, then my transmission will stay happy with my less demanding driving.

 

[Coffey1]

That's my thoughts to mike if oil is good for more heat and all the other things why change.
I didn't buy a car or 50k pickup I like the feel of driving a TRUCK.
And the synthetic's in my opinion would be a waste of cash.

 

[MuleMac01]

Update.. Removed the spin on filter drained the new dex 3 into a 5 gal bucket and added 10wt like in the video.. shifting issue still present.. wont go into 3rd unless I take my foot off the throttle. On a side note the tranny temp was down a little in this Las Vegas heat..

 

[acme66]

[PS: Come and visit us in Nevada City Montana and take a ride. It is one heck of a trip, 14 miles, about 6 of which will feel like they are straight up. 8500 feet in elevation right to the foot of a mountain and through more than a dozen mines and 5 old towns. I can no longer offer camping at our place because the 923 is parked there but I can recommend both with and without services. (read paid or free) Mention SS and I will discount the whole group 50%.

You got a website for your tours?[/QUOTE]

It is rough but operational. Except the email, that seems to be broken.

www.nelsonoffroad.com

Ken

 

[lindsey97]

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