I have installed a couple of Trans coolers on previous cars. Did one on my 99 C5 and on my 96 Talon Turbo AWD.
I installed this cooler on the lower right side of the AC condenser as I had on my 99 C5. It is spliced into the trans fluid return line as suggested by B&M, Hayden, and Derale instructions

 

That's an indication that a problem is being covered up by the cooler.

Also, a hot trans causes more aggressive lockup, not a lack thereof.

 

Not sure I follow. The cooler was just installed a few days ago.
I haven't noted any difference in lockup.......but then perhaps I don't know what to look/feel for.

 

Maybe a little expensive but DeWitts will be the end of your problem

 

Thought about that and had a DeWitts from my 99 that I tried to use but the trans connections changed in 01 and I couldn't locate adapters to fit the 01 trans lines to the old style threaded cooler connections on the DeWitts.
But the issue is with trans temps, not water temps so I don't think the radiator is the issue here.

 

Update 8/11

Well to make things more difficult my 03 started throwing EBCM related codes soon after my last post on this back on 7/16. I traced and checked wiring but had no luck so I took her to a local performance shop that I have used over the years. They do many Vettes and have great techs. I provided them with all the trans temp test results that I had posted up on CF. I talked directly with the tech that tested for the overheating. He drove my 03 trying to get the trans to show the temps I recorded for over two hours in 90-100 degree days. He said he drove several hills as well as city streets and couldn't get a temp over 198. He checked the trans fluid level, it was fine and said the fluid looked clean, was not darker in color, had no off smell. So he did not know what else to do at this point. And I didn't have any suggestions either........weird results for now, but good news.
The daily temps over the last three weeks in this area have in the high 90s to low 100s. This is much higher than normal for western Oregon. I saw temps as high as 110 on the outside temp sensor on my van......so couldn't have asked for better temps to test overheating.

Fixing the EBCM codes took a long time as there were some shipping SNAFUs with the off site repair shop and the "fixed" EBCM that was shipped to my shop turned out to not be fixed ;^(. It was shipped back for redo or replace.....but when returned to my shop it was labeled as 'Non-repairable" ;^(
So I ordered a brand new ACDelco EBCM today for $559.00 shipped and it will be installed and tested when/if it arrives at the shop next week.

I will follow up once I have her back and run my own trans temp tests again.

Thanks,
Jim

 

I used to have this issue, with my procharged car. Now I have a tranny cooler and my temps don't go past 170.

 

Thanks,

I did install a B&M Trans Cooler 70264 back on 7-19-17.

But the trans temp tests I did right after the install did not show the improvement I was hoping for.

I posted this on 7-19
------------------------------
First test after installing a B&M 70264 SuperCooler 7/19

Outside temps ranged from 78 -87 degrees. AC on for test
Mix of city and freeway
Cold start showed sitting in the garage all night.

Time Coolant Trans Oil
3:08: 149 75 88
3:18: 201 142 174
3:23: 214 179 194
3:40: 214 190 212
3:43: 201 192 214
3:52: 207 176 210
4:03: 214 192 216
End of test.

So over an hour of driving a mix of city and freeway with temps 78 -87 degrees with AC on for test. The trans still got up to 192 twice in an hour.

I don't consider this much of an improvement.

 

Just an update,

Nothing new on the trans temps other than the shop tech says he couldn't get it to overheat driving it up hills and in 90-100+ temps.

I will be taking my new $$$ EBCM to the shop tomorrow (8/17/17) and while there I will discuss the Converter with the techs.

Will advise when they are done with my car,

Jim

 

Update:

My 03 is back home from the shop

I want to sincerely thank all who offered their knowledge and suggestions to me during this.

Transmission heat issue:

Shop reported that they found the trans was 3/4 of a quart low, fluid was clean, no smells, not discolored. They topped it off. Drove several trips on days in the 90s and saw trans temps of 174-178.

At my request, they hooked up a Tech2 and checked the trans data to see if TCC was locking and unlocking. Data verified that the TCC was working properly.

I also asked the tech, in person, who did the driving if he could feel the TCC lock up. He said he could.....but he said he didn't feel it unlock which I thought was odd.

I drove the 03 home in 80 degree weather over several hills and stop and go. Trans temp was 133 when I started the car, temps rose during the drive to about 178 and stayed there for most of the trip. In the last 6-10 miles of slow in traffic driving the temp reached 185.

I will continue to monitor the trans temps.

Thanks again,

Jim

 

Foggy,

Today when I picked her up, I also asked the tech who did the driving if he could feel the TCC lock up. He said he could.....but he said he didn't feel it unlock which I thought was odd. But the Tech2 has no records of trans or converter issues.

Weird.

Thanks for all your help with this.

Jim

 

I still don't understand why it runs hotter than my truck. IMO you shouldn't be over 150.

 

My understanding is all C5s run hotter coolant and trans fluid compared to other cars.
I know that my 99 ran hotter than the other cars I have owned.....but over 190 for the trans is just too hot for my comfort.

But perhaps other will let us know how hot their C5 A4 trannys run.

 

My coolant temps were in the mid 190s stock. Now with an unshrouded Spal fan they are 187-190 on the highway. I suppose if OP is hitting stop and go that would deive the temps up. I'm commanding my fans on much sooner than stock.

 

Good advice...I have a 160 tstat and run170 to 200 with cool trans numbers.

 

You prob need to give some TLC to your cooling system... Coolant, Clean debris from radiator & condenser.


All this was checked and done before I posted the original question.
The radiator was removed, cleaned both the radiator & condenser and pressure tested at a radiator shop, new hoses, new coolant, new 180 thermostat, and properly "burped". The coolant temps were never an issue.

 

Update,

So far nothing much has changed.
Still seeing temps up to 196 after just a couple of hours of driving around town and freeways with the AC on and outside temps around 78-87 degrees.

Jim

 

You've shown much patience with your issue, you get a gold star for that.

 

Thanks so much for the kind words,

I have to admit that I am pretty short on patience at this point. I wish I knew what was actually the GM designed "operating temp range" for the A4. I appreciate everyone's opinions and what their A4s seem to operate at but these results seem to vary quite a bit.

I would really like to ask Evil-Twin about this as I suspect he knows exactly what the GM designed "operating temp range" for the A4 is.
But he doesn't accept PMs, which I understand, as his InBox would be constantly full

I keep wondering if I am just chasing my tail and that the A4 may be just operating as designed.

My next step is to add a pusher fan to the B&M Trans cooler.....but there may not be enough clearance to the fan to the shroud.

 

I think you're OK with the cooler now, but there is no reserve for when you decide to beat on the car or you get stuck in conditions that tax its cooling more.