Is my transmission running on the hot side?

[TonyT]

While on the highway the transmission generally runs about 85 or 90C when in cruise. However in stop and go traffic in the city it will easily hit 100C/212F While going up long grades, once in a city freeway at 80 kmph and twice on long highway grades it has hit 105C/220F. And it cooled down to 95 C within five miles going down the grade.

The fluid seems to still be pink to me But then I generally don't drive it much on long highway grades or city stop and go traffic. The transmission was flushed about two years ago as the mechanic then said the fluid was burnt. The transmission cooler was power washed. .

I get these temperatures from a Bluetoooth OBD2 reader device and Android software on my phone.

The problem though is I have a 800 mile haul of a 3,000 or 4,000 lp trailer coming up in summer as I'm moving to another province to be closer to family due to severe vision problems I have just encountered. Granted this will be on the Canadian prairies so only a few shallow river valies and a few small cities to drive through so not that bad. We'll be keeping the speed down just to be on the safe side and probably in third gear. (Given my catastrophic vision impairment problems mentioned in inother thread I have a cousin coming out to drive my vehicle and trailer for me. Hopefully the docs can get my vision cleared up enough that I can still drive.)

Are these temps a problem? Should I have a third party transmission cooler installed to be on the safe side?

My vehicle is a 2003 Trailblizer EXT with I6 and 4WD.

 

[Mooseman]

The temps are in keeping with the engine temperature since it is cooled by the cooler in the radiator. In all vehicles that come into my hands that have an automatic tranny, I always add an auxiliary cooler, whether it will be towing or not. Heat will kill trannys so the lower you can keep it, the longer it will last. Somebody had posted a graph of longevity vs temperature which shows it very well.

Dexron VI fluid is better than the old Dexron III so if it wasn't filled with that, I would recommend that you flush it. Even then, if you haven't driven it much, it would still be OK with Dex III. Check all your fluids. Was the transfer case fluid changed lately? It is usually forgotten and has a relatively short service life. Wouldn't be a bad idea to also replace the fluid in both diffs as well.

I have towed with the exact same setup and it will tow it just fine. Just keep it in 3rd gear all the time. I towed a 4 place sled trailer from Ottawa to Huntsville, no problem. Just going uphill it's a bit underpowered but will make it.

Good luck and hope your vision improves.

Edit: Just saw that you already said that you have an aux. cooler. How big is it? The bigger the better.
Edit 2: Is your fan working correctly? That could explain why it's going up when stopped.

 

[TonyT]

Yes, I've had most of the fluids changed including the transfer case and differentials. Not the brake or power steering fluid. Doesn't it come with a tranmsmission cooler from the factory? As far as I know it does not have an aux cooler.

Are there any brands of auxiliary cooler that you or others would recommend? What is the usual time to install such? I'm looking for basic and not fancy. I want to ensure it works for my upcoming trip.

Yes, my fan is working. I can hear it whirring away occasionally while in stop and go traffic in the city. I live in a small town so it never has a chance to warm up that much around town. When that happens and I check the engine temp it's at about 105 C.

 

[Mooseman]

Yes, there is one built into the radiator but it is immersed in hot coolant from the engine so I consider it marginal at best. Not sure about brands for an aux. cooler but I do know that plate type is better than the el-cheapo tube and fin type. Found that thread with the chart as well as more info:
http://gmtnation.com/forums/topic/9702-transmission-coolers/

and this is basically how mine looked when installed. Same type and size:
http://forums.trailvoy.com/attachment.php?attachmentid=5474&stc=1&thumb=1&d=1246630233

 

[TonyT]

Thank you very much for the link. 105C isn't that bad then at least not for short periods of time. That takes a load off my mind. Hmm, I found the dealer invoice for the transmission flush. (Love my paper scanner.) They are a Chrysler dealership and used 18 L of VU02152 lubricant. Dealer parts guy said it was ATF+4 so that looks like it's a Dexron IV equivalent. He thought it was the synthetic stuff.

 

[Mooseman]

I hate to tell you this but:

http://www.mobil.ca/Canada-English-LCW/automatic-transmission-fluid_mobil-super-atf-plus4.aspx#

Mobil ATF+4 is not recommended for vehicles that require Ford Mercon® or General Motors Dexron® type fluids.

I think you should flush it and use the proper fluid, again, I recommend Dexron VI.

Why go to a Chysler dealer with your GM? That would be like going to a vet instead of a human doctor. Sure he could probably do something but it's not recommended except during a zombie apocalypse

 

[sawicksted]

My 03 TB pulled a 4000lb travel trailer over 3000 miles in a two week period last summer from PEI to Boston through to the Adirondaks , then on to Algonquin and then back through the states to boston back up through Maine to the east coast. Yes you'll see it working hard in the hills but that's to be expected. Make sure you do all the fluids and that the trailer brakes are working well and you should have no problem in the prairies!
Good Luck

 

[TonyT]

Why go to a Chysler dealer with your GM? That would be like going to a vet instead of a human doctor. Sure he could probably do something but it's not recommended except during a zombie apocalypse

Because the GM dealer in town does not have a good reputation. My mechanic did not have the equipment to flush a transmission so he recommended the Chryslers dealer.

 

[IllogicTC]

Because the GM dealer in town does not have a good reputation. My mechanic did not have the equipment to flush a transmission so he recommended the Chryslers dealer.

Makes sense. While there's stuff that GM-specific going on with the design and particular fluids and whatnot, there's also at least a fair share of commonality between all types of vehicles.

Kinda reminds me of Dematic with the thing they started doing a while back - they'll come in and fix any brand of conveyor. I mean of course they'll provide full support and parts and warranty stuff for their own brand, but they'll service any brand. "But I have Hytrol, it makes sense to call the Hytrol guys!" Because some things are just too common or shared between manufacturers.

 

[RedEnvoyDenali]

Here is the temp chart I think you were referring to:

I would add my thumbs up to installing a cooler as well. Cheap insurance against expensive tranny repairs/replacement.

 

[The_Roadie]

The truck is rated to tow its specified rated trailer with the factory cooler, but it won't do it forever or 100% of the time, and still get reasonable tranny longevity. But aftermarket coolers are only in the $40-75 range, so it's almost not worth debating brands or their merits. They are ALL adequate and better than the factory cooler alone. I would recommend it on ANY truck used for towing more than a 1000 pound trailer - which is anything that also requires a truck brake controller.

 

[IllogicTC]

The truck is rated to tow its specified rated trailer with the factory cooler, but it won't do it forever or 100% of the time, and still get reasonable tranny longevity. But aftermarket coolers are only in the $40-75 range, so it's almost not worth debating brands or their merits. They are ALL adequate and better than the factory cooler alone. I would recommend it on ANY truck used for towing more than a 1000 pound trailer - which is anything that also requires a truck brake controller.

The only ones I've seen from people around here are just regular air-cooled units, with a dependency on air moving over it while moving or the effects of convection to remove heat. I wonder if there's any with an auxiliary fan? Something that senses higher temperatures and activates the fan to help. Could be useful in an emergency cooling scenario, but is also some extra wires to run in addition to rerouting transmission lines.

 

[Mooseman]

If you install it in front of the radiator, it will get constant air circulation from the fan.

 

[TonyT]

My 03 TB pulled a 4000lb travel trailer over 3000 miles in a two week period last summe

Just curious, did you occasionally monitor the transmission temps on that trip?

 

[TonyT]

If you install it in front of the radiator, it will get constant air circulation from the fan.

And presumably while driving. My fan never goes on while driving on the highway. Well, maybe on a long mountain grade but I can't say I noticed this last trip in B.C. on the Coquihalla. The only time it ever goes on is in stop and go traffic while in the city in the summer. Actually usually just at stop light and it goes off after thiry seconds or a minute or so. I've very succesfully avoided almost all rush hour traffic for the past 25 years.

 

[sawicksted]

Just curious, did you occasionally monitor the transmission temps on that trip?

Not with a "scan" tool but there were times in the mountains that we stopped and let the TB cool down as 40+C temps and hills were a little much at times. You could tell that it was getting too hot. That being said there were some very long 8-12 hr days of driving in very mountainous conditions and extreme heat.

Now I have a scan tool and my TORQUE APP / blue tooth obdII reader.

I also always take extra tranny fluid, oil, coolant, power steering fluid, and brake fluid. I know I'm over cautious but ......you never know when you might have to limp along to a garage and that little bit of oil might save your engine/ what ever.

 

[TonyT]

Now I have a scan tool and my TORQUE APP / blue tooth obdII reader.

I love that kind of technology. For not much money you can get a much better insight as to what is really going on. But then I'm a computer geek (and absolutely useless as a mechanic) so that interests me.

 

[TonyT]

A friend explained that the slightly better auxiliary coolers come with a valve that only runs fluid through the aux cooler when the transmission oil gets warm enough. This is of particular concern to those of us in Canada or northern USA states and winter.

 

[Mounce]

To answer the question about the coolers with auxiliary fans, yes, there are such things. They run about $150 or so though.

 

[TonyT]

To answer the question about the coolers with auxiliary fans, yes, there are such things. They run about $150 or so though.

We'll let the Americans towing in NV/AZ/CA in summer buy those units.

 

[Mooseman]

Even though the fan may not be engaged, it is always spinning from friction and thus, pulling some air. At highway speed, there is enough air going through to cool things enough. If anyone has any concerns about cooling the engine and/or tranny, they can run a switch to put 12V+ to the white wire to the fan for full engagement. The truck will sound like a jet engine and fuel mileage will suck big time.

 

[Mounce]

We'll let the Americans towing in NV/AZ/CA in summer buy those units.

Lol I didn't even see your answer when I posted mine.

 

[TonyT]

I had the auxiliary transmission cooler added and, under similar conditions, I would estimate that it's kept my transmission about 15C or 25F cooler.

When hauling my heavy trailer we hit a maximum of 105C and stayed around 100C much of the time unless going downhill.