IMO an auxiliary transmission cooler is definitely worth it. The stock cooler is small and insufficient especially if you do any towing or hauling

 

I agree.

I use a scangauge 2 to monitor temps and keep an eye on them as much as possible.

I'm always at the top end of my GVWR when I camp and having an auxiliary transmission cooler keeps my temps around 150-190 even in mid summer. WV has some pretty long/steep hills to climb and the added weight worried me before adding the cooler. I sometimes tow my camper and use 3rd gear while seeing the same temps.

I've observed oil temps as high as 225 and water temps as high as 215ish while camping in summer. I wanted to add these numbers because they're all related in my opinion.

My transfer case is typically 30 degrees warmer than my transmission temperature (exterior case measured with a laser thermometer). I'm not running the stock transfer case so others may have different numbers. I'm currently working on a solution that could help reduce the 30 degree difference.

I have not regretted adding an additional transmission cooler and think it will prove to be worth it for my application. It's probably not needed if it's just a simple daily driver but a lot of us on 355nation use our trucks for performance and need every advantage we can get.

Long story short.....it's worth it.

 

If you tow or haul heavy loads it is critical for trans life. Bigger is better here too!

 

I appreciate the input, and it looks like I'll be installing one tonight!

 

Keep this in mind when you install one. The air to your radiator's coolant now has an obstacle to overcome . Make sure you clean the surface of the radiator and trans cooler on a regular basis to have maximum air flow to avoid any problems.

 

With all respect to the OP, questions like this can never really be answered.
Worth it how?

No one can measure whether a transmission cooler is going to pay for itself in protection for your transmission. If you install one and your transmission lasts 300k miles, did the cooler help you get there? If you don't install a transmission cooler and the transmission dies before 150K miles, was excess heat the cause?

Most of the folks here (excuse me please, I don't mean to speak for every 355 Nation member) have a bias toward making it stronger, better. Many here are ready to drop a few dollars to make their vehicle "better than factory OE" (and that includes me).
Will a transmission cooler really be a good use of the money it costs?
Who knows? You can do it and then drive the truck for 20 years and you won't know for sure.

What you can know for certain is that heat is destructive to an automatic transmission, and a transmission generates heat from within while you drive (and absorbs some engine heat too of course). More heat is bad, less heat is good.

 

Thats a great answer, and I appreciate your input. I could have phrased the question better as I agree that no one can tell you that a trans cooler will save your transmission. I guess what I wanted to know was if there was a big enough drop in temp to warrant installing one. Like your last line states, less heat is good so I believe I will install one tonight. I pickup up a cooler at lunch.

 

Optimal trans temps are around 200* and as a reverence, even a small cooler like this B&M 70268 (11" x 7-1/4" x 3/4" model is rated at 13.000 BTU) will help drop the temps 15*-20* with 100*+ outside temps. I personally like having the extra insurance. One thing to consider is geographical location. they do make coolers with built in by-pass to make sure it reaches at least the minimum operating temperature. I think this is the one time too cool is not always better. In another recent post, a member mentioned changing the oil/filter every 25k instead of 50k. something I plan on doing also, again, fairly cheap insurance imo. https://www.355nation.net/forum/how...how-miscellaneous/9161-how-install-transmission-cooler-your-colorado-3-5-a.html

 

Optimal trans temps are around 200* and as a reverence, even a small cooler like this B&M 70268 (11" x 7-1/4" x 3/4" model is rated at 13.000 BTU) will help drop the temps 15*-20*. I personally like having the extra insurance. One thing to consider is geographical location. they do make coolers with built in by-pass to make sure it reaches at least the minimum operating temperature. I think this is the one time too cool is not always better. In another recent post, a member mentioned changing the oil/filter every 25k instead of 50k. something I plan on doing also, again, fairly cheap insurance imo. https://www.355nation.net/forum/how...how-miscellaneous/9161-how-install-transmission-cooler-your-colorado-3-5-a.html

I live in North Georgia so I does not get too cool around here. If it did, then I could always cover the cooler with some cardboard until it hits operating temps. This isn't my daily driver so I'm not too worried about it.

 

I am with Rick on this. Can't prove it will help, but put it in a few years back. Satisfied I did. Did not have means to check temperature until about a year after I put it in. I run T-oil temps around 195+ when fully warm. Water runs 195-210 most of the time, up about 5 degrees maybe.
The only concern is that mine does not have bypass valve so trans temperature might get to 150 if I am doing short trips.

 

I have trans cooler and temp gauge inside. As well as an external fluid filter. Trans runs 30 degrees cooler the. Engine temps most of the time.


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Thinking of it... I might be inclined to add an external spin-on filter for the transmission before trying to get an additional external cooler stuffed in there.

One member here a while back posted of putting a Derale single-row tubular cooler in the transmission-fluid line underneath the radiator.

http://derale.com/products/fluid-coolers/transmission/heat-sink
.

.

 

One benefit of a trans cooler is that you can remove some load from the radiator and engine by bypassing the trans cooling circuit in the radiator. On heavy duty applications that can make enough difference to eliminate engine overheating and improve trans cooling at the same time.
My old '81 Suburban struggled with cooling when it had a stock 350 & TH400 trans. I quickly tired of that and built a 463" big block with large engine oil and trans coolers.
Big motor but still using the same radiator, never again went over 200F even towing very heavy loads in the summer. Even though it had fairly low compression and built to run 87oct leaded regular gas, it was seriously stout (fast!) for a 4,800lb+ truck in the late 80's. By the way the engine was a .030" over 455 Buick. Funny, the truck is long gone but the engine and trans are still on a rack in my garage. Gee, in a beater 355 I'd bet 12's would be easy even on 87oct unleaded and no computer would be required.

 

One benefit of a trans cooler is that you can remove some load from the radiator and engine by bypassing the trans cooling circuit in the radiator. ...

I believe this.
Is there space for a large enough cooler to bypass the OE in-radiator cooler on a 355?

 

Don't tow in OD.......... I stay in 3 while towing (my 2010 automatic has 1,2,3,OD(maybe D) positions). While not towing, if I know I will not be going any faster than 50mph for any length of time (ie. a few miles at least), I stay in 3 position. I use OD when I know I will be not towing and cruising at 50mph and higher for some distance. If you watch your RPMs and MPHs, you can shift between 3 and OD on the fly. A friend of mine once told me (he was a transmission mechanic for several years), that people tend to burn up the OD because they use it all the time, instead of just when it would really benefit the most.

 

I have a manual trans & have never worked on a auto 355 so will pass on suggestions for front mounted trans coolers. That said it would be easy to mount a cooler (engine oil or trans) under the bed & strap on a 6" 12vdc muffin fan with or without a simple Klixon bi-metal thermostat mounted on the oil line.
I have also used a 3/8" ID X 6' or 7' long finned tube for trans cooling on big block dirt circle track cars. It was under the car and inside the frame rails and it worked OK (not great) as long as it wasn't totally covered with mud.

 

It was a little more of a pain to install than I thought, but I got the cooler in last night. These are my temps after a 30 min drive on the interstate.

 

It was a little more of a pain to install than I thought, but I got the cooler in last night. These are my temps after a 30 min drive on the interstate.

Can you tell me how you got the trans temp to show on your scan gauge. I’ve tried everything I’ve found on here to make it read trans temp. And all has failed.


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There is a code that you have to enter. I dont have it with me right now, but I'll look after work and let you know.

 

I’d GREATLY appreciate it. Thanks


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Pics of the cooler installation?
Purchase details? (manufacturer, model ?)

 

I'll get some pictures when I get home tonight after work. This is the cooler I bought: https://www.autozone.com/drivetrain...mission-oil-cooler/compressor-works-transmission-oil-cooler/238922_716520_19735

 

nice selection of hardware here:
Thermal Switches | susa
Specialty Fittings | susa

http://www.setrabusa.com/products/oilcoolers/diff-gearbox/index.html

Oil-cooler adaptors with thermal switching built in to bypass the cooler on warmup:
Oil Thermostat | susa

 

nice selection of hardware here:
Thermal Switches | susa
Specialty Fittings | susa

Setrab Differential / Gearbox Coolers | susa

Oil-cooler adaptors with thermal switching built in to bypass the cooler on warmup:
Oil Thermostat | susa

I can tell you I didn't use any special fittings when I installed it. I cut the cool line back to the transmission and flared the ends. I then pushed the hose on it and used good ol' hose clamps. No leaks so far!

 

Here’s pics of mine. Sorry I didn’t get it before I put the grill back on. I relocated the horn a bit to fit the cooler In there. Then the added inline filter


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I need to make a bracket for the other side of the cooler, but have it supported with zip ties for now.

 

Using this? Yeah I’ve tried this numerous times on past. And a gain right now. I
Just get a blank


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In the txd line I can’t seem to get the parenthesis around the last 2 numbers


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You don't need the parenthesis, just make sure the 01 is there. If your scan gauge set to use cansf?

 

I’m not sure. Should it be?


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Let me check mine.

 

I tried changing it to Cansf and it stays on connecting on the screen


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Ok, I just double checked my settings and have it set as follows:
Mode: VPW
TXD: 6C10F122194001
RXF: 046205190640
RXD: 3008
MTH: 00090005FFD8
NAME: TFT

I have a 2006 extended cab 2wd with the 3.5L

I could have sworn that I got it from that page, but must have been mistaken.

 

Now that works. The txd line was way off from the site. Do you happen to have engine oil temp or oil life or anything. THANK YOU


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The scan gauge tft is very close to the auto meter trans temp I added. I read that from the test port. Sorry to get off track on your thread. Thank you so much for your help.


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