Reese at MTI has been naking "further adjustments" to the PCM on my 04 SSR. The other day, I needed to do some testing on the roads near the shop, and happened to look at the transmission fluid temperature guage (its the rightmost guage on the 03-04 accessory gauge package). To my surprise, it was at a notably higher reading than I had seen before.
Normally, the gauge starts out at the "cold" end of the gauge (below "100"), and works its way upward as I drive, but it had never gotten past the "210" mark before. This particular day during the testing, I saw it hit about halfway between 210 and 280 marks, or 245.
When I got back to the shop, Reese and I analyzed it a bit, and Reese even connected the EFILive diagnostic cable to check the reading. By that time, the gauge reading had declined to about 225, and the diagnostic cable verified that as being accurate. So, the 245 reading had almost certainly then been accurate too.
When we analyzed it, we realized thee were 2 factors at work that day:
1. It was a hot day - probably mid 80s at that point
2. I had been doing standing start acceleration tests, checking some new settings.
Now admittedly, my SSR has been "warmed up a bit" in terms of performance, but not THAT much.
During the drive home, under more "normal" acceleration conditions, I noticed that the guage was still at about 220 degrees. Later that evening, after it had cooled a few degrees to 77 degrees, I did some more testing, and found that under cruise condtions, the gauge was agin around 210, but when I accelerated hard even just a couple of times, the temperature agai climbed to 245 or very near that (no mark at that point on the gauge).
I did a little research at a number of transmission and general automtoive websites, and that got me concerned.
It seems that with an automatic transmssion operating at "normal" temperature, the fluid will last 100,000 miles. That's the good news. The bad news is:
1. "Normal" temperature is 175 degrees
2. For every 20 degree increase in temperature, the life of the transmission fluid is cut by HALF.
So, at 210, 35 degrees above "normal" 175, the life of the fluid is cut down to something barely above 25,000 miles!
At 245, the life is at least theoretically cut down to about 9000 miles.
So, you say, we probably never STAY at 245 for more than very short times. Well, here's the hard reality:
1. When I STOPPED the testing, eahc time it took at least 15 to 25 minutes for the fluid temperature to return to the 190 to 210 level.
2. More significantly, if you start hauling a trailer around (like a number of folks on this website want to do), that temperature goes up, maybe even higher than the 245 I experienced with NO trailer, and STAYS there for as long as you are pulling the trailer.
This, and the small engine radiator, may explain why the tow rating is restricted to 2500 lb.
I'm thinking that a transmission cooler makes a LOT of sense for an SSR.
Why is this transmission, which is used in countless other GM vehicles, running so warm in our SSRs? Well, first of all, that transmssion was designed for CARS more than for trucks. Our SSRs weigh 50% more than a Corvette, and at least 25% more than fullsize sedans. In fact this marginality is proven by the fact that the 05 SSR has the STRONGER automatic, rather than the standard one.
Well, if it needs an oil cooler, why didn't GM put one on? Easy. Cost.
Fortunately, transmission coolers are NOT expensive. In fact, your local U-Haul place makes that a recommended option on ANY hitch installation they do, and they charge only $100 to $200 for it, depending on the vehicle.
Now, if you are like me and want to do it RIGHT, you might consider both a heavy duty version of a cooler rather than a cheap one, and also better tubing connecting the cooler to the transmission.
The heavy duty coolers have a better type of finning that dissipates heat much better, and are also often physically larger in both fin area and piping size (to avoid flow restriction that can affect the operation of the transmission).
Cheap tubing will likely be rubber and will have cheap fittings. Good (expensive!) tubing will be braided stainless steel, and will have high quality, reliable and leakfree fittings.
The cost of a GOOD transmission cooler, lines, fittings, and labor is probably well beyond the U-Haul pricing. But, if you do the math on both (a) cost of a COMPLETE fluid change in an automatic tranmission (can't just "drain" it), and (b) the cost of a transmission overhaul when the transmission fails (heat is what kills an automatic transmssion, not just the fluid in it), the cooler, and a higher quality one at that, starts to look VERY cost effective.
I'm going to find me one.
Jim G
Normally, the gauge starts out at the "cold" end of the gauge (below "100"), and works its way upward as I drive, but it had never gotten past the "210" mark before. This particular day during the testing, I saw it hit about halfway between 210 and 280 marks, or 245.
When I got back to the shop, Reese and I analyzed it a bit, and Reese even connected the EFILive diagnostic cable to check the reading. By that time, the gauge reading had declined to about 225, and the diagnostic cable verified that as being accurate. So, the 245 reading had almost certainly then been accurate too.
When we analyzed it, we realized thee were 2 factors at work that day:
1. It was a hot day - probably mid 80s at that point
2. I had been doing standing start acceleration tests, checking some new settings.
Now admittedly, my SSR has been "warmed up a bit" in terms of performance, but not THAT much.
During the drive home, under more "normal" acceleration conditions, I noticed that the guage was still at about 220 degrees. Later that evening, after it had cooled a few degrees to 77 degrees, I did some more testing, and found that under cruise condtions, the gauge was agin around 210, but when I accelerated hard even just a couple of times, the temperature agai climbed to 245 or very near that (no mark at that point on the gauge).
I did a little research at a number of transmission and general automtoive websites, and that got me concerned.
It seems that with an automatic transmssion operating at "normal" temperature, the fluid will last 100,000 miles. That's the good news. The bad news is:
1. "Normal" temperature is 175 degrees
2. For every 20 degree increase in temperature, the life of the transmission fluid is cut by HALF.
So, at 210, 35 degrees above "normal" 175, the life of the fluid is cut down to something barely above 25,000 miles!
At 245, the life is at least theoretically cut down to about 9000 miles.
So, you say, we probably never STAY at 245 for more than very short times. Well, here's the hard reality:
1. When I STOPPED the testing, eahc time it took at least 15 to 25 minutes for the fluid temperature to return to the 190 to 210 level.
2. More significantly, if you start hauling a trailer around (like a number of folks on this website want to do), that temperature goes up, maybe even higher than the 245 I experienced with NO trailer, and STAYS there for as long as you are pulling the trailer.
This, and the small engine radiator, may explain why the tow rating is restricted to 2500 lb.
I'm thinking that a transmission cooler makes a LOT of sense for an SSR.
Why is this transmission, which is used in countless other GM vehicles, running so warm in our SSRs? Well, first of all, that transmssion was designed for CARS more than for trucks. Our SSRs weigh 50% more than a Corvette, and at least 25% more than fullsize sedans. In fact this marginality is proven by the fact that the 05 SSR has the STRONGER automatic, rather than the standard one.
Well, if it needs an oil cooler, why didn't GM put one on? Easy. Cost.
Fortunately, transmission coolers are NOT expensive. In fact, your local U-Haul place makes that a recommended option on ANY hitch installation they do, and they charge only $100 to $200 for it, depending on the vehicle.
Now, if you are like me and want to do it RIGHT, you might consider both a heavy duty version of a cooler rather than a cheap one, and also better tubing connecting the cooler to the transmission.
The heavy duty coolers have a better type of finning that dissipates heat much better, and are also often physically larger in both fin area and piping size (to avoid flow restriction that can affect the operation of the transmission).
Cheap tubing will likely be rubber and will have cheap fittings. Good (expensive!) tubing will be braided stainless steel, and will have high quality, reliable and leakfree fittings.
The cost of a GOOD transmission cooler, lines, fittings, and labor is probably well beyond the U-Haul pricing. But, if you do the math on both (a) cost of a COMPLETE fluid change in an automatic tranmission (can't just "drain" it), and (b) the cost of a transmission overhaul when the transmission fails (heat is what kills an automatic transmssion, not just the fluid in it), the cooler, and a higher quality one at that, starts to look VERY cost effective.
I'm going to find me one.
Jim G