Transmission- how hot is too hot?

[SULLVERADO]

Hey fellas just wondering how hot is too hot for these transmissions. I have a 2014 reg cab 4.3 work truck that spends 99% of its time off the pavement. I was on my way to work this morning in the woods and I was in 4x4 pushing snow and spinning and the temperature was up to 110 degrees Celsius (230 F) just wondering how hot is too hot and if there was a warning? Thanks

[O_J_Simpson]

When it gets hot, the light will tell you. When it gets too hot, you will be forced to idle the engine.

[sdeeter19555]

I think I remember someone stating the trans would trigger a overheat light at 250 or 260 degrees Fahrenheit.

 

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[powerhaulic]

If Temp's are regularly over 210f trans life will be significantly lower

I would install an additional cooler

 

I just returned from a long trip pulling an 8000# camper, never saw over 185f

[last truck]

You must have a extra cooler my truck can't do that without a trailer.

http://www.silveradosierra.com/transmission/2014-6l80e-temperature-control-unit-t319770.html

[powerhaulic]

Yes it is a max tow (NHT)

No aftermarket coolers just what gm installed

[07Softail]

I took my bypass t-stat out hasn't gotten over 170 running it hard with a Blower and converter.

 

RT

[Jon A]

Hey fellas just wondering how hot is too hot for these transmissions. I have a 2014 reg cab 4.3 work truck that spends 99% of its time off the pavement. I was on my way to work this morning in the woods and I was in 4x4 pushing snow and spinning and the temperature was up to 110 degrees Celsius (230 F) just wondering how hot is too hot and if there was a warning? Thanks

 

 

That temp won't hurt anything for short periods of time occasionally but if that's the kind of driving you do every day keeping the temps lower will help your fluid last longer.

 

At low speeds, where the torque converter is unlocked much of the time, it builds a lot of heat. More coolers won't do any good as you have plenty of cooling capacity--it's just not "turned on." While your water temps were probably a bit above normal, they weren't high enough to turn on your fans very high so you had little airflow through your existing cooler.

 

You can fix this with a tune. Unfortunately there's no parameter that controls the fans based upon transmission temp directly so you need to do it indirectly. Do this by having the fans come on more aggressively with increased engine temp and raising the minimum fan speed.

Also helpful is a lower temp engine thermostat--it will make the in-tank cooler in your radiator more effective with lower water temps so you can maintain the same tranny temps with less fan speed. I wouldn't go lower than 180 for a truck that sees snow though.

 

----------EDIT-------

 

On first read I missed the fact you have a 4.3. I'm not sure if all 4.3's got the external air-oil cooler for the transmission. Check and see--if you have it all the above applies. If not, adding an external cooler will be needed for the fans to do much good.

[truckguy82]

At 233 I have a small amount of smoke/steam coming out of the transmission dipstick tube and a very slight burning smell.

 

My fluid is still perfectly colored after many many trips to 220 degrees.

[sdeeter19555]

If Temp's are regularly over 210f trans life will be significantly lower

I would install an additional cooler

 

I just returned from a long trip pulling an 8000# camper, never saw over 185f

While this was the accepted standard at one point, I'm not sure that holds with today's fluids and transmissions?

 

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[powerhaulic]

While this was the accepted standard at one point, I'm not sure that holds with today's fluids and transmissions?

 

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the temp charts I have observed have not changed

[sdeeter19555]

the temp charts I have observed have not changed

I don't doubt that, but I think they are outdated and based on Dexron III.

 

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[powerhaulic]

I don't doubt that, but I think they are outdated and based on Dexron III.

 

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If that were true, I doubt the coolers included in my NHT would be keeping oil temp below 190 towing 8000#+

Dexron VI is no different in wanting to be cooler than 200, yes syn oils do tolerate more temp but clutch plates and bands only take so much heat

[sdeeter19555]

If that were true, I doubt the coolers included in my NHT would be keeping oil temp below 190 towing 8000#+

Dexron VI is no different in wanting to be cooler than 200, yes syn oils do tolerate more temp but clutch plates and bands only take so much heat

Mine runs 120 towing that kind of weight, what's your point? That has nothing to do with outdated tables meant to sell you oil changes.

 

Have a nice night.

 

 

 

 

 

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[truckguy82]

Diesel guys are like...so I hit 280 degrees today

Thread is like, ehhh man don't worry about it, you don't have problems until 300.