Good fluid for cold temps

[Righteyeblind]

I had my fluid (Dex 6 stock from GM) gel in the cooler in my 09 2500hd work truck yesterday.
Figured I would do some digging to find a good fluid with a real low pour point. i picked up some Mobile Delvac Synethic. It is Allison TES-295 approved and has a pour point of -65F which I thought was fantastic. Only cost $153 for 5 gallons.

Figured Id let some of you cold weather people know.

 

[hondarider552]

That is mighty cold I do say.

 

[GeneralTJI]

That mobil delvac synthetic is great fluid.

I remember hearing that dex 6 likes to freeze much quicker than most other atf....

Interesting to see a thread about it really happening. How cold was it when this happened?

 

[Righteyeblind]

That mobil delvac synthetic is great fluid.

I remember hearing that dex 6 likes to freeze much quicker than most other atf....

Interesting to see a thread about it really happening. How cold was it when this happened?

It was -50F when it gelled. But it showed signs of it at -40F too. After id let it warm up for about 20 min the trans temp would be 160. That's crazy since it never gets above 90 while driving. So I figured the gel wasn't letting fluid flow. Hope my converter and pump are okay but we'll see.
I had to build another guys trans last winter cause he smoked his cause Dex 6 gelled in the cooler. Dex 6 says its pour Point is -50F

 

[Mike L.]

GM never did any cold room testing on the Dex 6 before they released it into production. OOPS! Dex 6 is also not compatible with the pump seals and will destroy them if you retro this fluid back from '07. Allison had to deveop a new compound for the seal and certain other rubber pieces for the earlier Alli.

 

[Righteyeblind]

Trucks with DEX 6 are dropping like flys up here! Talked to a couple people today who's trannys are smoked cause of the same shit.
Make sure you get rid of the DEX 6 if your in the cold!
I pulled my pan today and lots of material in it. Now its in limp so looks like I hurt it.
I wanted to bump this up so it doesnt happen to you.

 

[Mike L.]

Dex 6 will hurt the front seal and nothing else. Clutch material in the pan is from another reason.

 

[Burn Down]

Dude, you got some luck Don't take it to Aurora

 

[Righteyeblind]

Dex 6 will hurt the front seal and nothing else. Clutch material in the pan is from another reason.

If there is no fluid flowing do to it being gelled in the cooler lines and caused the temp to get to 200 deg when its -50 that would hurt something inside would it not? Not allowing enough pressure to the clutches causing slippage? or no fluid going to the converter?
Wouldnt this be true?

 

[Mike L.]

If there is no fluid flowing do to it being gelled in the cooler lines and caused the temp to get to 200 deg when its -50 that would hurt something inside would it not? Not allowing enough pressure to the clutches causing slippage? or no fluid going to the converter?
Wouldnt this be true?

Cooler fluid is not pressure. It is the hot fluid the converter is discharging for cooling. That fluid becomes geartrain lube for the planetary. The pump is working with plenty of oil.
If cooler fluid is blocked, the converter will go into meltdown because of heat and the planets will turn blue from lack of lube. The clutches will only get damaged in extreme heat. I've seen this too many times.

 

[Chris611]

If cooler fluid is blocked, the converter will go into meltdown because of heat and the planets will turn blue from lack of lube. The clutches will only get damaged in extreme heat. I've seen this too many times.

Is there a relieve valve in the trans that allows flow of the fluid to the planetaries even if the cooler is plugged?

A lot of mobile equipment use a thermal bypass (basically a relief valve) on the return hydraulic filter (low pressure) to allow the oil to bypass the filter during extreme cold start up. Once the oil warms up, the fluid will then go through the filter. Sounds like GM needs one of these on these trans...

 

[Mike L.]

The later models have a drilled hole between the 2 cooler fittings.

 

[THEFERMANATOR]

I know for a stock trans the prefferred fluid to use in cold temps is TRANSYND or a TES-295 compatible fluid, but what about guys with built trannies? Is a DEX III type fluid still good down that cold? I wish I knew of a fluid that had DEX III's shift characteristics, but ran cool temps like TRANSYND did. My trans temps went up a good 30 degrees doing nothing but switching from TRANSYND to DEX III.

 

[Righteyeblind]

Cooler fluid is not pressure. It is the hot fluid the converter is discharging for cooling. That fluid becomes geartrain lube for the planetary. The pump is working with plenty of oil.
If cooler fluid is blocked, the converter will go into meltdown because of heat and the planets will turn blue from lack of lube. The clutches will only get damaged in extreme heat. I've seen this too many times.

So the material could be from the converter possibly? Since this has happened multiple times?

Albert, no shit right?! Damn my luck. I called aurora and they said the 15th is the soonest they could look at it.

 

[coldLBZ]

Right now I'm running Amsoil Low Viscosity ATF. It was recommended to me when my trans was built. The coldest it's seen is about -40 C without a bumper cover. I did notice that it runs slightly warmer in the summer though.

 

[MaxPF]

I had my fluid (Dex 6 stock from GM) gel in the cooler in my 09 2500hd work truck yesterday.
Figured I would do some digging to find a good fluid with a real low pour point. i picked up some Mobile Delvac Synethic. It is Allison TES-295 approved and has a pour point of -65F which I thought was fantastic. Only cost $153 for 5 gallons.

That makes the Delvac superior to Transynd, which has a pour point of -54°F according to the latest Castrol product data sheet (dated 2011) that I just viewed. The best I have seen is Redline D4 (Dex III spec) and D6 (Dex VI spec) that are both rated -76°F. 5 gallons of either will set you back $230

 

[Burn Down]

That makes the Delvac superior to Transynd, which has a pour point of -54°F according to the latest Castrol product data sheet (dated 2011) that I just viewed. The best I have seen is Redline D4 (Dex III spec) and D6 (Dex VI spec) that are both rated -76°F. 5 gallons of either will set you back $230

Hmm, ever run any in a built transmission truck?

 

[MaxPF]

Hmm, ever run any in a built transmission truck?

Nope.