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Can anyone tell me what the normal operating temp for the Allison is? I was driving around town today and noticed the tranny temp gauge was reading nearly 200 degrees. I am not familiar enough with the Allison to know whether or not this is normal. My previous truck(2500 w/6 litre) only ran that warm when I was plowing snow. Thanks in advance.
 

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Mine get's to 200 or more in stop n go traffic in the summer. The Allison has low flow at idle, so driving like that will increase the temp of the sump. The 04's have a change that resolves this by adding an additional solenoid and programming. According to Allison, 220 all day is not a big deal. There testing is done at 250 and above according to them. The only thing running a higher temperature does is reduce the life of your fluid if you are not running synthetic. No, that being said, I have a larger transmission cooler that I have replaced the OEM with. It dropped the temps down where I never got over 180 and it would still heat up to 160.
 

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Seems like I remember reading about checking the transmission fluid that to accurately check it must be in the normal operating range of 150 to 200, so I guess I'd use that as a guide.


Personally on my truck, it seems to run between 140 and 160 most all the time, even towing. I've see it up around 200 during a couple of conditions. The first condition was pulling the travel trailer in stop and go city traffic. The other condition was running off road on the sand dunes with lots of full throttle starts while hill climbing.
 

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The highest temps I have seen are over 200 deg while driving around town in stop and go traffic on a warm So_Cal summer day. Driving across the Desert and pulling a trailer with outside air temp at 110 deg, the tranny runs cooler than the 200 mentioned above.


So its interesting what Chuntag95 mentions above, a change to the tranny. Why the change if 200 is OK per Allison?








On edit - maybe when pulling a max load in stop-n-go traffic it would go way above 200?Edited by: OC_DMAX
 

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Mine gets real hot when traveling on big mountain highways when pulling 12-20000lb trailers. I think the hottest its ever gotten was around 200.
 

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OC_DMAX


I have pulled 20,000 in stop and go traffic in 95 deg weaqther and not had it go above 200 or so, of course I was in tow/haul though.
 

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OC_DMAX,


The change is because of the medium duty 2000 and 2400 more than the 1000 series. They seem to be much harder on them and have more overheating problems due to PTO use and the like. The 04 guys got the benifit IMHO.


I'm an engineer and overkill is my nature. Why put in one screw when 3 will do?
I have also replaced several trannies down here due to heat related failures. If fluid degrades as it gets hotter, then I don't want it hotter. There is, of course, the middle of the road temps you need to be in. I want to be between 140 and 190. I was hitting 210 and even 220 at times. (Those temps really reduce the life of your fluid.) That was with no load, not towing, not romping on it, just traffic. Even though I went with synthetic transmission fluid, I still don't like to push it when it comes to temperatures. I don't like anything above 200 anywhere, oil, water, tranny fluid, blinker fluid,
you name it. I watch all of my gauges like a hawk since I had a thermostat stick closed and darn near melt my engine cause the idiot light didn't come on. I have gauges in that vehicle now and will in every vehicle till I'm dead. I run synthetic in everything but the brakes and they have a racing fluid with a very high wet boiling point. I still flush them every year or two to boot.


Now, would I recommend this to everyone? No. Some of the guys in Alaska and Canada or along the border shouldn't consider it since you will almost never get the temps to those levels. Had I not been getting above 200 every single day, then I might have left well enough alone. For me with more than 20 days a year over 100 degress, it makes sense. If the Allison is the "weak" link and heat is what kills 90% of transmissions, then heat reduction and control is a good preventative action.


I know that Allison says it's no big deal and I'm sure they are right for most of the transmissions they make. I'm not a lucky person, so I like extra insurance like extra coolers and synthetic fluids changed at non synthetic intervals. I even asked Allison what it would take to put in the changes in the 04. It was a lot more than I could do in my driveway, so the extra cooler will have to do. Heck, I have not one, but 2 extra fuel filters.



My way is not for everyone. It works for me and I sleep well at night. I have to drive this till my 4 year old daughter is out of college, according to my wife. I have had 2 injectors fail, 3 injector cup seals leak and the Allison valve body replace due to a sticking valve all in 30K miles. I still love my truck and trust it with my family. It has not broken for the same thing twice. Where I felt the system was lacking, I added what was needed. I am about out of stuff to repair, so I should be good for a while now. <IMG onMouseOver="this.style.cursor='hand'" onMouseOut="this.style.cur
 

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OK,


I edited the post above and changed 210 to 200 deg. I can never keep the scales on the oil and trans gauges straight. So I meant to say 200 deg F after looking at the gauges in the truck (mid scale trans temp). Not much difference though.


If I drive around town with the Tow/Haul engaged it helps slightly. Seems very dependent on outside air temp.


A64Pilot - is yours a Chev or GMC out of curiousity? The Chevys have the bow tie directly in front of the trans cooler, while the GMC is more open (I believe).


I have had a new Chev truck every two or three years. The prior truck was a 2000 Chev 2500 with a 6.0L gas engine. Whenever I pulled my trailer plus motorcylces to the desert (about 7K pound load total - not much compared to some of you), the transmission temp gauge would rise up slightly when pulling hills, but when the viscous (sp) controlled fan kicked on, the temp dropped immediately. On the DMAX with same exact load, once the temp builds up in the Allison, it stays for a long time. Does not matter how many times the fan comes on. The trans temp is also very dependent on the outside air temp. Looks to me like the cooling capacity of the air trans cooler is just marginal. So I changed to Transynd and will just live with it. Just my thoughts.





Regards,


Alan
 

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I was talkin to Chuntag and he even has filters behind his brake light bulbs to keep his lights clean!! I was trying to sell him on a windshield washer tank recirculating pump w/ filter but he is still deciding on that
 

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dmaxalliTech said:
I was talkin to Chuntag and he even has filters behind his brake light bulbs to keep his lights clean!! I was trying to sell him on a windshield washer tank recirculating pump w/ filter but he is still deciding on that

Guilty as charged.
I can't help it. You can always make it better.
 

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OC,


It's an 01 chevy, 70,000 miles and dexron, I know I should be running transynd, just haven't found the time/money yet.
 

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I was trying to sell him on a windshield washer tank recirculating pump w/ filter but he is still deciding on that.


Hmmm, not a bad idea. Might keep those microscopic scratches out of the windshield, where the wipers run.
 

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I did not like the way my transmission heated up in stop and go traffic and would not cool down for a long time even at hiway speeds, so I removed the plastic Chevy symbol from my grill and made a custom emblem out of aluminum with about 100 5/16" holes in a matching pattern. I mounted the new emblem and drilled the holes through the plastic in the grill. This did help the transmission temps greatly and it now cools down very quickly at a return to hiway speeds. My transmission temperature now stays at basically 70 degrees above the outside temperature and has never been above 180 degrees even when I pull my trailer after this little modification. This is just my cure for the cooler being in a poor location in my opinion. Edited by: Blue Max
 

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I installed the FRED scoop. Made a big difference in the cooling.
 

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PICTURES!
PLEASEEdited by: Amric
 

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Hard to see it here. Best bet is to see if Fred has any pictures.
 

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Here are some pictures, but I have not washed the bugs off for a while. I also need to repaint due to rock chips. I have installed a grill guard after my grill modification and it probably added 5 degrees to the tranny temp.
 

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I tried the Fred Scoop, but with the lack of air flow in traffic, it didn't do much good. The 2x+ sized cooler did the job. As a matter of fact, I just recieved the AN-12 to Jiffy Tite connectors last night. They made me up some from scratch since they are not a part.
This will allow me to mount the new cooler in the same orientation as the OEM without any hoses.


I was really impressed with Jiffy Tite and their support for a guy trying to mod his truck for better cooling. They were even going to pass on my info to GM. I do need to get back with them as the fitting threads are about 1/8" to long for a good seal, but I can trim them down. Like I said, they are a class act IMHO.


Remember the old saying, there is more than one way to cool a tranny.
 

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The lack of air flow thing is why i did not do the scoop and the fact that it blocks off the other cooling systems. I did gain cooling just sitting in one place due to the easier air flow and that was my origional goal.
 

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Funny, I live in Charleston, S.C. 90+ degree temps with 90+ humidity constantly. Never seem to run anywhere near 200 degrees with the tranny. Only time it got hot on me I was towing the trailer in Friday evening stop and go traffic and forgot to put it in T/H. Dropped it in T/H and ran a few blocks and the temps came right back down.
 
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