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Max Temp for 6L50 Transmission?

35334 Views 31 Replies 17 Participants Last post by  DieselDrax
I remember a few members saying they have got their transmissions fairly warm while towing, think the highest was 225? I also believe I remember the number 250 degree's and below being thrown around on one of our threads as "safe" for the 6L50.

I got to researching and seeing if there are any upgrades to the trans (after posing my truck pulling thread) and came across this article:

http://etereman.com/blog/general-mo...for-the-6l50-transmission-in-your-2010-camaro

It just gives you somethings that you can do to the trans to help it. It's for Camaro applications, but I figured they might work for us since we use the same trans, right? Found a shift kit and some other mods when I searched TransGo.

Anyways, if you read the bottom of this article, it says that if you operate the trans above 200 degrees for very long, you will shorten the life of it considerably....so I tried searching for another article, say a spec sheet from GM on the 6L50 to see what they said the max temp was for our model year trucks, thinking that maybe they updated the trans or increased the cooling ability since they attached this trans to a truck that has the ability to tow a decent amount and very well could get fairly warm. I haven't had any luck finding such an article yet.

I did find some other info on it though, from another forum. It gave various info, but the part that caught my attention was the Service Interval section. It states that; "Replace transmission fluid and filter at 45,000 mile intervals if operation falls under 'severe' service category.'" Below, it defines severe service as being; "vehicles that have been used to tow frequently, have been driven primarily in heavy city traffic during hot weather, or that have been driven primarily in hilly/ mountainous terrain."

This transmission reminds me of the Allison 1000 transmission that the full size Duramax's have, in that they are meant to have the fluid and filter changed on a regular basis like engine oil. You could get by with longer intervals on the Allison if you didn't tow as much and used Transynd (or one of the other Allison approved oils) Synthetic trans oil and go 50,000-100,000 miles between changes. If I have to do that with this transmission, that's fine. But what isn't fine is if that statement about the 200 degree max temp, is actually true.

Does anyone know any differently on this? Can you add a transmission cooler (I have read that they exist for the trans/ truck combo) as well. Thanks for the input.
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There is already an integrated transmission cooler in the radiator. I dnot know if you could add another external cooler but it seems possible.

There was also another company working on a deep sump reservoir for the 6l50, the extra capacity should also reduce temps.
I'm at 194° just sitting in dang mall traffic
Drove through the mountains w/ about 1k of payload a couple weeks ago. Pretty steep road w/ switchbacks and hairpin turns. Used the exhaust brake and transmission was in manual mode. Saw temps in the 218-220 range
Drove through the mountains w/ about 1k of payload a couple weeks ago. Pretty steep road w/ switchbacks and hairpin turns. Used the exhaust brake and transmission was in manual mode. Saw temps in the 218-220 range
These temps seem pretty warm, but the more I hear about these new transmissions it seems pretty normalish.
I've always heard over 180° you're killing your trans. But these trans don't have shift bands and they have magical fluid
Magic fluid, huh? :) That is good to know though. It does seem warm but like you said, maybe this is normal for these trucks.
I've seen up to 195 just towing an empty trailer in traffic. My guess it's like most modern engines (running hot). If 250 is the safe number, I wouldn't go past 240.

Also I haven't checked, but can we service the transmission or is it sealed? Maybe try a different brand of oil (Red Line Synthetic would be my choice).
Yep I'm think it just runs warm. I'm at 204° right now just taking an empty trailer across town
I believe they are serviceable and that the oil can be changed. I don't know where the fill tube is though...I don't recall seeing a dipstick in the engine bay?
I believe they are serviceable and that the oil can be changed. I don't know where the fill tube is though...I don't recall seeing a dipstick in the engine bay?
I believe there is a fill plug on the side of it. Fill it until it comes out like a differential
I believe there is a fill plug on the side of it. Fill it until it comes out like a differential
Good way to overfill it.

Follow the sticker on the pan. Take out the plug on the pan, start filling through the hole on passenger side of the trans where you would expect a dipstick to go in. Once fluid starts to out where the pans plug was start the truck, shift from park to revers to neutral to drive then neutral, reverse and finally park. Make sure each position engages before moving to the next. While still running add more fluid until it slowly drips from the pan’s plug. Replace both plugs. You are now done.

Just did it this past Sunday and is a common procedure for GM transmissions.
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When I was pulling a 6'x12' Uhaul across South Dakota this summer, outside temps mid-90's, close to 100. If I recall, my tranny temp was pushing 220 if I remember right. Maybe even 225. I was a little concerned, but didn't experience any transmission issues and figured, truck was under warranty and if it went, it went. I now have about 23,000 miles on the truck, if there is a dipstick, maybe i'll pull it and see what color the fluid is.
Knock on wood, the only issues I have had with my truck is DEF fluid related and the exhaust.
Hi Guys! had been having 220-225 tranny temps without towing at freeways and uphill climbs since new. Looks the radiator oil cooling isn't sufficient. At nearly 80,000kilometers, my tranny just gave up - Torque converter damaged, 4-5-6 input shaft broke in 3 pieces (1 part inside the TC, 1 inside the pump and 1 at the input hub), and the hydraulic pump distorted. Dealership had to renew the whole internals except for the housing and TCM. Mine may have been an isolated case or a manufacturing flaw as the units we have here were made in Thailand.
I don’t understand where the heat issue comes from.
At least in 5th or 6th gear it should be in lockup.

So if your running fast enough to be in 5th there should be no slippage and very little heat.

If your pulling a trailer on a back road and the transmission is in 1st to 4th and or shifting a lot then yes it’s will be hot as it will not be in lock up. And the torque converter would be hot.

Ideas ?...
You may have a restricted cooler line or low flow rate right from new.
I would (or have dealer) disconnect cooler lines and ensure they are completely clear.
I had a cooler line plugged years ago.
Transmission operated properly right up to the point it failed.
During change out I blew out lines to clear any contaminated fluid and was shocked to find a bunch of filter media limiting flow.
Ok it seems there is a lot of information about these transmissions running hot.
There is also a suggestion that these transmissions are a weak link when it comes to our trucks.
So
If Ford is using the GM / Ford co designed 10 speed in the new ranger !! Why is GM using this weak link in our trucks?
To many of these dinosaurs on the shelf? Need to get rid of them ?

Not sure about you guys but I have never driven a vehicle with such a quirky transmission as this 6L50
Some times I get a big increase in RPM during a shift. Mostly going into 3 or 4th. Keyword during the shift.
You can hear and the rpm rise between gears during the shift.
Sometimes there is a mushy shift and other times a harsh shift.

It’s like the programming for the transmission was written by Microsoft on a bad day......

Rob
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Yep the trans shifted like sh*t all the time. With or without a trans tune.
Yep the trans shifted like sh*t all the time. With or without a trans tune.
Mine shifts pretty darn smoothly after the tune (Jason Hacklers tunes).
Mine too. After tune. GDE.
I wonder if people are revving the engine up with too much pedal as if driving a gasser.
Instead of letting it short shift allowing the engine to torque its way up to speed .
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