Yes, but finding a trustworthy independent transmission shop is difficult, to say the least. So I try to get independent input before I contact local shops.

Thanks,
Jim

 

If the engine had a misfire it'd be buried in a DTC. You could pull the codes to be sure. There may be a code for the brake switch, but again you'd have to pull it. If you car has a DIC you can pull codes from every module. I don't recall how it's done but if you give it a search on here you're bound to find it. I'd install a cooler regardless, but it still sounds like the trans is running too hot without. Unless you're a leadfoot, that would also do it. Try that last test again but this time keep pressing down on that brake pedal until something happens, even if you go farther than what it would take to unlock the TCC. Just do it slowly and gradually.

 

Thanks again for taking your time to help!

I have pulled all the codes several times recently. The only codes that reoccur are C1284, C1287 which are related to the Traction Control.
I will install a cooler, but I think there is something wrong and want to locate it before it costs me a transmission

 

8VETTE7, Thanks for the help. Went out and did as you suggested.

Here is what I did:

7-16-17 Trans temp test

Checked Coolant level cold, right on the line

Re-burped using top coolant pass over. With Rad cap off (new 15lbs) both sides started to leak coolant as soon as I loosened the bolts. Let them run a bit and tightened them back down.

Pulled radiator top cover and took a good look at the radiator....very clean. Reinstalled everything before starting her up.

Outside temp 73f

Time Coolant Trans Oil
Cold 110 75 forgot

Started and turned on the AC, both fans fired right up.
Turned AC off and started the test.
Todays numbers are with car sitting still on my driveway

Time Coolant Trans Oil Notes
11:41 201 113 140
11:44 207 129 151
11:46 212 136 154
11:48 217 145 163
11:50 219 151 169
11:52 225 163 181 Fans still not On
11:54 216 169 189 Fans On then Off
11:56 225 172 190 Fans ON
11:58 217 178 198
12:00 217 180 201 Turned on AC, both fans went High then Off
End of test.

Really hard to see the left fan. So results were based on the right fan.

Thanks to all,

Jim

 

Good question, I wasn't thinking about it much until I noted the Trans temps on the trip. So I really can't say.

Jim

 

B&M 70264 SuperCooler on the way...........

Anyone think this could be a bad temp sensor on the trans ?

Jim

 

Seems unlikely, they generally work or go full hi/low. I'm curious about your driving style. Do you get on it a lot and force frequent downshifts? I've never monitored trans temps on a car with only a radiator cooler, but I imagine the temps would be in the 200 range for a normally functioning car? Someone else feel free to correct me if I'm wrong on that one. My truck with a 4L80E has a factory auxiliary cooler and usually runs 150-165. When towing with the TCC locked it stays 165-180.

 

Thanks SC,

That is what I assumed as well regarding the temp sensor......
This is my daily driver except in snow and ice. I am not hard on it and do not drive it hard or track it.
I will install the B&M Cooler and see what happens. Just hope serious damage has not already been done.

Still open to all suggestions

Jim

 

Update,

Installed a B&M 70264 SuperCooler today hoping it would resolve the trans temp issue.
Based on the first test I am disappointed with the results.

Here is todays after install test run:

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.

Thoughts?

Should I get a larger cooler? The B&M 70264 that I bought is rated @ 14,400 BTU.
Their next largest, the 70266 is rated at 20,500 BTU, then the 70274 is rated at 29,200 BTU Rating

Jim

 

Let's see install pics

 

Tomorrow...........maybe. Pretty sure I will be replacing this one.

 

You have an issue with the transmission ... All the cooling in the world won't fix that.
The stock cooling system is very capable. I think you're wasting money on coolers.
You need to find WHY the trans is running so hot.... NOT just treat the symptom

 

My vote is a converter not locking. That trans shouldn't have gone above 150 if that cooler is properly installed.

 

Just dropped her off at a local shop to be evaluated for the trans temp and the Codes that keep happening: C1284, C1287.

Will post up what they find.

Thanks,
Jim

 

I Commented here in error, and regret wasting others time.

I do enjoy learning abut the various systems, and might learn to keep the yapper on a leash one of these days.

 

Hopefully this will help put the torque converter issue to rest. If your converter is not locking at highway speeds you will get a P1280 code which is "transmission slipping". Evidence this code is thrown will show up when you exit the highway and come to a stop. Upon initial acceleration the 1-2 and 2-3 shifts will "bang" for lack of a better term and you will definitely think and feel that something is wrong.
What has happened is that when the code is thrown the PCM will command full line pressure to the trans to try to correct the slipping because is doesn't known the cause. Could be converter, clutches, valve body etc. Now because full line pressure has been commanded the 1-2 and 2-3 shifts will happen under non-modulated line pressure thus the very hard, not firm, shifts. Shutting off the car and waiting 5 minutes or clearing the code (even while driving) will revert line pressure back to normal.
So I believe you have no issue with the converter based on your posts with no mention of the hard shifts. What I haven't read yet is anything about the fluid. Have you confirmed it is at the appropriate level? Have you inspected it to see if it has a dark/brown color or smells burnt? I don't feel 229 degrees is overly excessive and will not damage the transmission. It is however not the norm for these cars.
I do think the cooler, if installed in a location that exposes it to direct fresh air flow, should reduce your numbers but only during highway travel. Air flow at in town speeds with all the stop and go will not reduce temps much if at all.
Good luck and hope the trans shop can shed some light on your issue.

 

My thought was more along the lines of the TCC not being conmanded to lock and therefore not commanding full line pressure on the shifts. I broke a 4L60 case once with full line pressure.

 

If the TCC isn't commanded it's because one or more conditions exist such as a 450 rpm difference between engine speed and trans input shaft speed which it would consider a slipping condition thus applying full line pressure. Another condition not allowing TCC apply would be if the trans was operating in a hot condition, 266 degrees and above, in which case it would also not allow the trans to shift into 4th as well. The later is also a sign the trans is not overheating as the OP is able to drive in 4th.

 

I appreciated your comment, my time was not wasted.

Jim

 

Thanks for your info,

No transmission codes have surfaced during this and I have checked them every day since posting. No hard shifts at all noted. I posted that I had a Chevy dealer check my transmission fluid level right after the new parts were installed and they added .4 of a quart. They made no comment on the condition of the fluid, but I failed to ask. But the pan was not pulled. I guess pulling the pan, replacing the filter and pan fluid will be the next thing done at the current shop. 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
Should hear something today.............

Thanks to all,
Jim