Transmission temperature question

[Gordo]

I am setting up mu 02 Avalanche to haul my 22' trailer this summer. A quick look under the hood and I only see a puny little cooler running vertically up the drivers side. Is this a cooler for the PS? My truck is Z71 with trailer towing. I would have thought it would have had a decent size cooler on it. Can I read the transmission temp theough a scanner? Or do I need to actually install a temp sensor for this. Not sure if my truck has the sensor. I has the blank on the dash to install a gauge but no gauge.

Thanks!

 

[Conner299]

I would recommend getting an OBDII scanner and the Torque Pro app, if you have android. It would initially be a cheaper, and less invasive option, than trying to add a gauge. Both in time and money. A scanner can be had for around $20 to start, and the app is $5. I know in my TrailBlazer, I can pick up trans temp with it. Even if you can't, in your Avalanche, the app is well worth having. Especially since you can read CEL codes, and clear them after the problem has been resolved.

 

[Gordo]

I have a scanner now that plugs into my laptop. Only really used it for clearing the check engine light. I would buy one that dash mounts and can give me the temp readout if the whole system is capable.

 

[Mark20]

You can read the transmission temperature through the ODB port. I use a Scan Gauge II to read the transmission temperature in my Envoy. My Silverado tells me the transmission temperature through the Drivers Info Center.

The cooler you mention sounds like power steering. My Silverado has a separate transmission cooler in front of the radiator. Its about 9x8 inches.

 

[Wooluf1952]

The standard trans cooler is inside the radiator. You wouldn't see it on the outside.

 

[nospark]

Hello, I have the driver info center on '07 tahoe. What trans temp would be considered to hot?

 

[Mark20]

With a factory towing package and external tranny cooler on my Silverado I typically see 165 - 170 F in the summer when NOT towing. 180's to 190's F when towing with an occaisional shot over 200 F. Cooler in the winter.

 

[{tpc}]

I'll add to Mark20's post above that before I added the external tranny cooler (factory one) on my 07 tahoe, I saw temps in the 180-190s (maybe even higher) when NOT towing. Now my temps are almost identical to what he described.

Everyone has an opinion on whats too hot and whats not, and there are a couple of charts floating around here (and the rest of the internet) on the subject.

I would say that consistent temps above 200 for long periods of time would be detrimental to the tranny, and anything approaching the 220 range even for a short period of time would make me extremely nervous. But thats just my opinion, and I am about as far as you can get from being an expert on the subject.

 

[DocBrown]

The factory cooler is most likey fine unless you are really pushing the towing capacity of your truck. Is this a travel trailer or something else? A travel trailer is just a box and has lots of wind resistance. So long as you tow in 3rd and keep the torque convertor locked most of the time you'll control trans temps fairly well. Boats and other types of trailers aren't nearly as hard on the truck.

When towing its perfetly fine to hit 200 for periods of time. Even 220 and above for VERY short periods. Again the key is minimizing shifts. My Sierra trans temps runs between 170 and 190 towing a 4700#, 21' travel trailer.

If you are not using Dex VI in the transmission, change out the Dex III NOW with DEX VI. It's a blended synthetic and supercedes Dex III in all GM transmissions that came stock with it. it runs cooler than Dex III. I used it my old TB, I sold the TB with 160k on and the trans was a strong as ever. And towed a trailer every summer for 8 years, once through the Rocky mountains. And that was without an auxillary trans cooler.

 

[neohio]

I am currently doing some research on adding a cooler and flushing the system on my wifes 05 Z71 Tahoe. I am leaning towards pulling off all the original GM lines and going with a braided style hose from the trans to an aftermarket cooler. Considering bypassing the rad completely. Also researching skipping Dex III and Dex VI completely for Allison TES-295 ATF. I am also thinking about installing a remote mount spin on oil filter for the trans. Not sure if it will make much of a difference though.

We are towing a 30' ultra-lite trailer with her truck and I want to keep the trans in it as long as we can. Right now I am still pricing everything out to do the conversion. Cheapest I have found the TES-295 ATF for is $161 per 5 gal bucket. If her temps drop, I will swap the TB with Allison ATF as well.

Allison claims 300,000 miles service interval. So I figure I can send out a sample to be tested every 50k and see how it progresses. I doubt we will ever reach the 300K though.

 

[HARDTRAILZ]

300,000 miles...I would still want to change the filter before then.

 

[{tpc}]

I am currently doing some research on adding a cooler and flushing the system on my wifes 05 Z71 Tahoe. I am leaning towards pulling off all the original GM lines and going with a braided style hose from the trans to an aftermarket cooler. Considering bypassing the rad completely. Also researching skipping Dex III and Dex VI completely for Allison TES-295 ATF. I am also thinking about installing a remote mount spin on oil filter for the trans. Not sure if it will make much of a difference though.

We are towing a 30' ultra-lite trailer with her truck and I want to keep the trans in it as long as we can. Right now I am still pricing everything out to do the conversion. Cheapest I have found the TES-295 ATF for is $161 per 5 gal bucket. If her temps drop, I will swap the TB with Allison ATF as well.

Allison claims 300,000 miles service interval. So I figure I can send out a sample to be tested every 50k and see how it progresses. I doubt we will ever reach the 300K though.

I'm not sure I'd bypass the radiator. I think it would have a much worse effect on the trans possibly running too cold in the winter? I would just add an additional cooler in addition to the one in the radiator and go from there.

Your issues with towing are going to be much less related to the cooler (you will still want one, factory, aftermarket, whatever though) and much more related to the weight of the trailer and the length of it.

We pull a 26 1/2 ft ultralight that weighed in at 4400 lbs dry, probably geared up in the 5k-5500 lb range. The tahoe does a superior job of pulling it, but I have no doubt that a longer wheelbase vehicle would be even better. Food for thought.

 

[neohio]

I'm not sure I'd bypass the radiator. I think it would have a much worse effect on the trans possibly running too cold in the winter? I would just add an additional cooler in addition to the one in the radiator and go from there.

Your issues with towing are going to be much less related to the cooler (you will still want one, factory, aftermarket, whatever though) and much more related to the weight of the trailer and the length of it.

We pull a 26 1/2 ft ultralight that weighed in at 4400 lbs dry, probably geared up in the 5k-5500 lb range. The tahoe does a superior job of pulling it, but I have no doubt that a longer wheelbase vehicle would be even better. Food for thought.

Our trailer weighs at 5400 as delivered. We had it on the scale prior to our first trip. We were 6700 loaded with food and other junk. Trailer is rated for 7000lbs. Tahoe has zero problems pulling it. It turtle hops a bit due to the short wheelbase over some roads. But nothing horrible. We will probably trade the Tahoe in next year. My wife wants a Diesel dually. Which more than likely means she drives my Trailblazer daily and I get the dually for my commute. Or I will get a third commuter car eventually.

It has the factory internal and external cooler in it right now.

300,000 miles...I would still want to change the filter before then.

I don't plan on running the truck the full 300,000 between filter changes. I plan on servicing the trans every 100,000 if we keep it that long. A 5 gallon bucket should last at least 3 full services on a 4L60. Maybe more.