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Old 12-19-2005, 09:50 AM   #15
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You will notice that most if not all instructions on aux coolers recommend taking the output of the internal cooler as input to the aux cooler. I know I've always used that recommendation on my external coolers and never have had a tranny problem in the winter.

If you do it in the inverse, you are just reversing all the good you have done by bringing the oil temp up to the water temps in the radiator. I consider that shooting yourself in the foot.

I will be checking my factory installed cooler in my van though. I am curious if they reverse this installation.

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Old 12-19-2005, 11:01 AM   #16
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Guys...

The internal cooler is bypassed on my burban and that is my concern. However they installed 19000gvw B&M supercooler as the external and positioned it 4 inches in front of the radiator. The thought as it was explained to me was not to allow engine heat to affect the running temp of the transmission.

What temp guage should I get and are they easy to install?
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Old 12-19-2005, 11:09 AM   #17
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Every GM vehicle I have ever owned or have seen that had a factory installed oil to air coolers installed have always gone oil to water then oil to air, then back to the trans. As a matter of fact, the 9C1 Police packages even have engine oil coolers too that go oil to water then oil to air, then back to the crankcase. I have no idea on used vehicles that have been modified, MOHOs, Ford, Dodge or any of the others. It is not good for a trans to be totally cold either. The reason I was told by a GM engineer I met that they install it that way is exactly as Toaster had posted, to get some heat to the tranny faster. Though to be very honest, the heat that it may add is nearly negligible based on my real world tests I did before adding an additional inline oil to air cooler. Though you can clearly bypass the oil to water, it was not advisable to do this when I asked. I have not modified the oil to water cooling setups and have well over 100k on some trannies that are in moderate to extreme service.

I got my trans gauge from http://www.egauges.com/ It was an electronic one. So what I did was place the sensor in the 4L60e's test port and based on a 12V neg ground, simply added postitve current to the gauge and presto, aftermarket trans temps (your mounting locations will differ)! The 3/4 ton Suburbans and trucks (newer) come with a factory installed gauge FWIW. As for bypassing the radiator, if you are not using the truck in cold climate, then you should be OK, but if the truck is used in cold climate, it should NOT be bypassed. As I said earlier, a bone cold trans is nearly as bad as a too warm one. As Jack pointed out, putting it to the oil to air first, then to the radiator is not a best practice from what I've gathered working on cars as a shade tree mechanic and talking and working with folks in the know for over 10 years.

GM does the exact same thing to throttle bodies on their engines too. They route hot coolant through the TB for cold temp issues.
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Old 12-19-2005, 12:24 PM   #18
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Quote:
Originally Posted by darryl97420
Guys...

The internal cooler is bypassed on my burban and that is my concern. However they installed 19000gvw B&M supercooler as the external and positioned it 4 inches in front of the radiator. The thought as it was explained to me was not to allow engine heat to affect the running temp of the transmission.

What temp guage should I get and are they easy to install?
The gage I am using if from Hayden. I bought it at Pep Boys for I think it was $40. Itís a kit that comes with a bung that can be installed in the transmission pan if there is not a drain. If there is a drain you should be able to screw it into the drain. I have put these on three different trucks and quite happy with them for the price.

Now on my Suburban I went and found a second temp sender and a fitting that allowed me to put the sender in place of the drain plug on the engine. I wired up a switch so the one gage can read either sender. I was able to get that sender at the parts store by bringing the sender with me and letting them look up the number off it. That lets me view both engine oil temp and tranny temp.
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Old 12-19-2005, 01:32 PM   #19
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Originally Posted by Silvertwinkie
Every GM vehicle I have ever owned or have seen that had a factory installed oil to air coolers installed have always gone oil to water then oil to air, then back to the trans. As a matter of fact, the 9C1 Police packages even have engine oil coolers too that go oil to water then oil to air, then back to the crankcase. I have no idea on used vehicles that have been modified, MOHOs, Ford, Dodge or any of the others. It is not good for a trans to be totally cold either. The reason I was told by a GM engineer I met that they install it that way is exactly as Toaster had posted, to get some heat to the tranny faster. Though to be very honest, the heat that it may add is nearly negligible based on my real world tests I did before adding an additional inline oil to air cooler.
See I'm not so sure it would be as dramatic as it sounds when you really think about it.

200F is the magic number you want to stay under for the transmission. Most fuel injected motors run a 195 degree thermostat. So at the radiator where the tranny cooler is you are probably seeing about 180. Thatís about perfect for the transmission.

The oil to water is very efficient compared to an oil to air. Now as long as the radiator has the cooling capacity to handle that heat then no big deal. You would not see a big difference in temps like you pointed out because the thermostat on the engine will keep it regulated.

When the car is designed they do it on the cheap. The radiator is just right for the thermal output of the engine and tranny. Its not designed to have much more then the needed cooling capacity. Put a 5k trailer behind it and now you are exceeding the cooling capacity of the stock cooler and possibly the radiator. So you add an AUX cooler to handle the extra demand. These take off thermal load from both the engine coolant because the tranny cooler is in the radiator. Problem is it hits the liquid to liquid cooler first so itís still doing the majority of the cooling.

A liquid to Air cooler will have a bigger thermal drop the more difference there is in the ambient air temp and the temp of the oil you are trying to cool. Knowing that then hitting the oil to air first makes sense because you are putting less load on the rest of the cooling system. The exchanger in the radiator will keep it consistent temp but will not put nearly as much heat into the coolant.

Now in my case I am exceeding the thermal capacity of the radiator under certain conditions. Actually the radiator can handle it but there are other problems. Oil cooler, Tranny cooler, A/C, Big block thatís tight to the radiator so the air dams on the front of the engine, 800lb of cast iron of the 454 and air flow restricted on three deep on other liquid to air exchangers. It just overcomes the cooling capacity the truck has even with the biggest 4 core that will fit the truck (well there is a bigger one off the diesel but it requires a different mount and I didn't know about it when I bought a new radiator).

What I want to see is if this plays out like I think it will. If I route it the other way if my tranny will run close to the same temperature and see if I can drop coolant and motor oil temps some. Then I want to see if relocating the AUX cooler out of the air flow to the radiator helps. If it doesn't then Be Cool or a Griffen radiator will be my next course of action.
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Old 12-19-2005, 02:56 PM   #20
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That is a bummer if the cooling capacity of the tow vehicle is poor, you're right it would have an impact.

Here is what I did and the results. Keep in mind your results may and most likely will vary:

Base line equipment-

1996 LT1 w/4L60e, deep pan trans, RAM air torque converter cover 3.73s, towing a 2004 25' Safari rated and nearly full to the GVWR of 6300lbs.

with 195 degree stat and oil to water, to air to trans, average trans temps were 175-195 degrees

with 160 degree stat same oil to water, to air to trans, average trans temps were virtually identical 175-195 degrees

Adding one additional in line oil to air into the mix the trans temps, outside of a few extreme robust grade tows, practically parked the trans at 175 degrees.

On the 2004 Stock Suburban 2500 6.0L with 4L80E, 4.10s, had one oil to water, oil to air then back to the trans, towing the same Safari.

With a 195 degree stat, the trans temps averaged between 170 and 190 degrees.

Same vehicle, with a 160 degree stat yielded nearly identical trans temp results.

In both vehicles the coolant temp decreased by at least 15 degrees based on actual PCM reporting FWIW by adding a 160 degree stat. So, even with the cooler coolant temps, it wasn't until I added a second cooler that it made a difference in heat reduction. Problem is that if I put an even lower thermostat in, or upgraded the radiator to try to get the coolant temp down enough to make a real difference, the engine would be hard pressed to go into closed loop, so I felt I was as low as I could go without getting other issues to come up, thus adding the second in line trans cooler. In theory, I should be able to yield the same results on the Suburban with either a second inline or a monster cooler.

The main reason I keep the oil to water in the mix is for the winter driving. On the Impala, on extreme cold days (10 degrees or lower), even warming up, I notice a bit of clutch slippage until the trans can get to a nice over 100 degree temp. In some cases, under extreme cold, the trans has to really work to break 100 degrees and that is the only reason I keep it (besides the engineer guy telling me not to). Now, I fully understand individual results may vary, however both my tests seem to indicate that the oil to water does very little, not zero, but not enough to putz with it and re-route a bunch of stuff. I found the biggest bang for my buck in my particular case was to add a second cooler air to oil cooler (or larger cooler), and keep the factory setup as is.

Now with the throttle body, that's a whole 'nuther story, I like 5 degree air getting consumed by the beast cause colder air is more dense and I get more power, but that's a whole 'nuther thread.

BTW Toaster, have you ever considered putting in an alum radiator instead of the factory type? A bunch of guys I know have done that mod, not cheap, but they did get lower overall temp with the alum vs. conventional cores. Problem is with the non adjustable PCMs of the mid to late 80's you gotta be careful on how cold you get that motor if I recall correctly...that darn check engine light came on if a guy in the car next to you broke wind not to mention that there is no reverse cooling on the older engines where the heads get cooled first on the newer engines allowing some room to play.
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Old 12-19-2005, 03:22 PM   #21
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I am trying to find confirmations but I swear I read the 4L60e and the 4L80e has a thermostat inside it that bypassed the AUX cooler till warm.

I'll keep looking tonight and see if I find a exploded veiw to verify
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Old 12-19-2005, 03:40 PM   #22
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You could be right....but when doing a full trans fluid purge on the 4L60e from a cold start (amb temp of about 60 outside), disconnecting the oil to air line to allow the fluid to be pumped out (while pouring fresh in the dipstick tube) means to me one of three things on my 4L60e....either that any type of thermostat may be broken to an open position, it goes to the oil/air at lower amb temps of about 60 degrees, or it doesn't have one. Not sure on the Burb yet...only has 6k on the trans...I figure in another few thousand, I'll put the Amsoil ATF in and find out.
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Old 12-19-2005, 10:56 PM   #23
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After checking with the RPO code list I learned that my truck has the GU4 or 3.08 ratio. From what I understand this rearend was intended to improve fuel economy. With my 700R4 tranny and 3.08 gears I don't think I should be towing anything much less my Argosy 28.

How difficult is it to change out the gears to the 4.10?
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Old 12-20-2005, 05:37 AM   #24
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After checking with the RPO code list I learned that my truck has the GU4 or 3.08 ratio. From what I understand this rearend was intended to improve fuel economy. With my 700R4 tranny and 3.08 gears I don't think I should be towing anything much less my Argosy 28.

How difficult is it to change out the gears to the 4.10?
About $180 for gears and $300 labor or a Junkyard axle with the gears you want.
Then change the drive gear in the transmission to get the speedometer acurate.
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Old 12-20-2005, 06:52 PM   #25
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Then change the drive gear in the transmission to get the speedometer acurate.
The gears are color-coded (naturally I forget which color a 4.11 would use). You can get he correct gear from your friendly GM dealer, they are not expensive.
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Old 12-20-2005, 07:08 PM   #26
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I had my 4L60E rebuild last month. It started slipping badly at the slightest hint of acceleration, coupled with a check engine light. It turned out that it was not cooked, not even the least bit. The fluid was nice and bright red.
The damn thing broke mechanically, literally. They showed me parts that came out of my transmission that just simply were broken and/or sheared off. No lack of lubrication evident. I did have them use certain aftermarket parts and a HD torque converter, on their recommendation.
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Old 12-20-2005, 08:55 PM   #27
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I had my 4L60E rebuild last month. It started slipping badly at the slightest hint of acceleration, coupled with a check engine light. It turned out that it was not cooked, not even the least bit. The fluid was nice and bright red.
The damn thing broke mechanically, literally. They showed me parts that came out of my transmission that just simply were broken and/or sheared off. No lack of lubrication evident. I did have them use certain aftermarket parts and a HD torque converter, on their recommendation.
While trying to find info to see if there is actually a thermostat in the 4L60's (neverdid find out) I ran accross a LOT of info about them breaking parts like shells and sun gears.

Here is an example.

http://www.smokemup.com/tech/700r4.php
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Old 12-20-2005, 09:21 PM   #28
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Quote:
Originally Posted by 59toaster
While trying to find info to see if there is actually a thermostat in the 4L60's (neverdid find out) I ran accross a LOT of info about them breaking parts like shells and sun gears.

Here is an example.

http://www.smokemup.com/tech/700r4.php
Interesting article. Only I never raced the burb ( yet) or did nitrous on it ( yet).
Los Angeles traffic and stop and go for hours does it just as well.
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