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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
 

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i learned from an old transmission man that using motor oil in transmission will drop operating temps by about 30% I have not used it in late model overdrives but on 350 and 400 turbos and C4 and C6s I have run it for years one of my service trucks ran it for over 10 years The trans man worked with me at a new gm dealership and for the 5 years we worked together every warrenty trans rebuild left there with motor oil instead of trans fluid and he never had a comeback. again I have NOT used in overdrives
 

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180 Degree thermostat:

This is one reason why I am such a big fan of lower temp thermostats. As long as the only trans fluid cooler is in the radiator (as on our SSR's), the trans fluid will NEVER get any cooler then the coolant temp (which as we all know - regularly can run in the 210 degree range on hot days with A/C on. So, in theory, just letting the vehicle idle on a hot day with the trans in NEUTRAL - will cause the fluid to exceed the safe level for long term durability. (IMO, with better quality trans fluids, I think 175 may be a little conservative, but I don't like to see my trans fluid exceed 200 degrees for any lenth of time). The reality is that automatic transmissions are so reliable, that if no one's fluid ever exceeded 200 degrees, 70% of all transmission shops would have nothing to work on! Now here is where, in the past, the masses pipe up and say "They're designed to run hot" (TRUE), "Aluminum engines run hotter" (NOT TRUE), "If it's not puking coolant out it's not too hot" (NOT TRUE), "GM knows what they are doing" (TRUE). Our vehicle's ARE designed to run hotter now-a-days on purpose, but it sure the heck isn't to make them more long lasting!!

An external trans fluid cooler (as Jim G. is going to do) is the hot set-up (pun sorta' intended), but it has to be done RIGHT (as Jim G. intends to do!). A universal cooler, some cheap rubber hose and a set of hose clamps will get the cooling job done at the cost of some potential reliability issues. Those hoses have a built-in sense to slide off the barb and pump all your trans fluid onto the road when you are furthest from any source of help!

So, the external trans fluid cooler will take care of your trans temps very nicely (you can take the transmission shop off your christmas card list!), but it does nothing to help out with aluminum cylinder heads that are living life "on the edge" in some key critical areas when that coolant starts to get 220 or so. Once again - the LM4 is not going to explode, or instantly sieze when (not IF on the SSR) the coolant gets to those temps, but it will adversely effect durability over the long term. Don't forget that it is not just the coolant temp that we should be concerned with. There are lots of variables here, but consider (on average) a coolant temp of 225 degrees can indicate a transmission fluid temp of 240, an engine oil temp of 300, and an exhaust valve seat temp into the four figure range (over 1000 degrees!) A cooler thermostat will handle these issues too if used in conjunction with a programmer to lower electric cooling fan activation temps. Of course the best set-up is an external cooler and a lower temp 'stat for more extreme conditions. Thankfully, all indications are that the OEM radiator has enough built-in capacity that it does not appear to be a limiting factor for most applications, although I know there are some members on here that were forced to go to custom radiators because of their rather "extreme" conditions! (When you make a load of HP - you also make a load of heat!).

Well, after all of that, you may be surprised to know that I still have the OEM thermostat in my SSR! I have however, reduced my fan on/off temps in an attempt to keep things very close to 200-205 maximum. The only reduced temp thermostat I can find compatable with the SSR is a 160 degree unit. My SSR is strictly a "weekend toy" and I am concerned that with a 160 my engine oil will not get hot enough to burn condensation and acids off on my shorter trip use. If my SSR was a daily driver - it would already have the 160 degree unit in there. So hey! Let me know if anyone hears of a 180 degree T-stat for our trucks, OK? :)

Blast

Check it out! I wrote a "Jim G." post!!
:lol :lol :lol
 

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I'm not cool...
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Jim G or Blast (you're both impressing the heck outta me)

what do you guys think we can expect from our poor li'l trannies :confused
when will you hypothetically hit the reliability wall Jim? whatcha thinkn'a doing then?
these questions have me thinking 05, but thats a whole new set of drawbacks :flag
 

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Discussion Starter #6
mikepowell: I wouldn't sweat it, if you are reasonable in your use of the vehicle. If you try to turn it into a 4750 lb dragracer, it's the wrong transmission, at least until you get it "built" by a transmission specialty house that knows how to stengthen it.

Jim G
 

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The 180 that the vet uses will work. You have to modify the port that the stat fits in. You have to open up the port by about a sixteenth of an inch. The sides of the thermostat are just shy of fitting. Once you do this it fits fine.
 

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Thanks for the tip!

Russr04 said:
The 180 that the vet uses will work. You have to modify the port that the stat fits in. You have to open up the port by about a sixteenth of an inch. The sides of the thermostat are just shy of fitting. Once you do this it fits fine.
Is this the late model C5-C6 application?

Thanks! Blast
 

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Discussion Starter #10
stfallet: Don't worry about the manual transmission or rear axle.

The Tremec is a performance transmission that works well even under racing conditions, let alone street. The rear axle only needs a cooler if you build a serious race car. Also, the axle used with the Tremec is much stronger that the one used with the automatic.

Note that with the axle used with the manual transmission, there are no provisions for traction control.

Jim G
 

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tbyrn has the SLP 160 and 180 t-stats that require NO modifications..04 models take just the t-stat while the 03 needs the housing also.


The fix for the trans in our truck is a 4L80E swap...The weak 4L60E has been known to be a weak link in all the later trucks for sometime now..


Just take a look at ls1tech.com ... Under the truck tanny section.
 

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Boosted said:
tbyrn has the SLP 160 and 180 t-stats that require NO modifications..04 models take just the t-stat while the 03 needs the housing also.
I checked with Tom (Byrne) via e-mail about 2 months ago. He responded very quickly - but only has a listing for the 160 degree. Same thing with SLP's website, 160 degree unit only.

Blast
 

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I'm still curious, when do you think you'll overpower yours Jim?

JimGnitecki said:
mikepowell: I wouldn't sweat it, if you are reasonable in your use of the vehicle. If you try to turn it into a 4750 lb dragracer, it's the wrong transmission, at least until you get it "built" by a transmission specialty house that knows how to stengthen it.

Jim G
it's good to know you can strenghten them :flag
 

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Jim,

"Note that with the axle used with the manual transmission, there are no provisions for traction control."

yes, yes, yes, yes, that's why I ordered one. Don't want to have any of that electronic s..t any more.

In March I was in Lenk (CH). Drove (with my Merc) onto a parking spot to make a u-turn. Gues what, they came with a baby tracktor to pull me off the snow/ice.

So much to modern electronics.

Let's get back to the time when sex was safe and racing was dangerous!!!!

Stefan
 

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BlastfromPast said:
I checked with Tom (Byrne) via e-mail about 2 months ago. He responded very quickly - but only has a listing for the 160 degree. Same thing with SLP's website, 160 degree unit only.

Blast
I am running hte 160 in my truck and the trucks cooling inabilities make it run closer to the 180 mark...
 

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stfallet said:
Jim,

"Note that with the axle used with the manual transmission, there are no provisions for traction control."

yes, yes, yes, yes, that's why I ordered one. Don't want to have any of that electronic s..t any more.

In March I was in Lenk (CH). Drove (with my Merc) onto a parking spot to make a u-turn. Gues what, they came with a baby tracktor to pull me off the snow/ice.

So much to modern electronics.

Let's get back to the time when sex was safe and racing was dangerous!!!!

Stefan
Actually I believe that the manual trucks still have the same rearend minus the sensors. Traction control comes from the vehicle pcm pulling timing and throttle out of it and applying some break when the sensor detects wheel spin. The rearend really does not do anything in that effect...
 

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Discussion Starter #17
Incrrect, Steve.

The axle on the manual is a different stronger one that has no provisions for the sensor needed for the traction control.

Jim G
 

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This is very hard to believe Jim. Maybe this is why GM is having such $$ trouble. They got away from a standard setup?

Even if this is true it still does not have anything to do with TC...... I will know shortley..Dad is looking up the rearend for me...
 

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Discussion Starter #20
Steve; The connection with traction control is that the difference in sensor speed versus what the PCM is expecting based on engine rpm and gear selected is what alerts it to the fact that there is a traction problem occuring.

This is also by far not the only place where the low volume status of the SSR made quick and easy adaptations more attractive to GM than a fully engineered, unique, and tested solution. I am not complaining about this. My purchase of my SSR was in PLACE OF purchasing a "street rod", and I KNOW the kinds of problems I would have faced there (VERY non-standard "engineering" there!). I REALLY like the SSR and am willing to tolerate some "issues".

Jim G
 
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