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Transmission & Oil Temperatures

112K views 66 replies 37 participants last post by  Danny Rose 
#1 ·
I have a 2014 Jeep Grand Cherokee Overland, and I am trying to gauge what 'normal' and 'high' transmission and oil temperatures might be, so I know how to interpret what is being displayed on the EVIC. Can anyone help?
 
#52 ·
About maintaining a constant trans temp. My oil is 195, my coolant is normal temp, yet trans is 100. Dealer had to let it idle 20 minutes, drive 10 miles, idle again for 20 minutes, drive another 10 miles just to get to 175. I drive 10 miles and get 100. I no longer see 195 as I have for 4 years. I've read about a 3-way valve, a thermostat by-pass valve, and thermal management system, but don't read anything about trans running too cold. Anyone experience this issue ??
 
#5 ·
Most of the 8-speed transmissions here are typically running at 195-205 (average) when fully warmed up (which takes a while from starting to drive). Although a previous poster indicated that it's "at its best" around 174 or so, when fully hot they're going to sit around the 195-205 range in the EVIC. I've seen mine as high as 215 in stop-and-go traffic but generally 195 seems to be it's settling point.
 
#8 ·
While towing my 6600 lb trailer my transmission runs at 195-205. My engine oil temp has run as high as 257 while towing the trailer up a 12 mile long 6% grade at 50 mph with an OAT of 60F. There has been a lot of discussion on this forum about what is a "normal" operating temp range for this engine. Chrysler remains mum on the subject, various diesel mechanics have differing opinions, and of course, forum opinions run the gamut. I've asked a Chrysler mechanic who is currently attending tech training on the VM 3.0 to see if he can learn what "normal" oil temp is for the VM 3.0. This is a real issue for those of us that tow heavy loads. The manual is vague on the subject. It just shouldn't be this hard...
 
#12 ·
While towing my 6600 lb trailer my transmission runs at 195-205. My engine oil temp has run as high as 257 while towing the trailer up a 12 mile long 6% grade at 50 mph with an OAT of 60F.

FYI
Mobil1 ESP 5w30 engine oil (which meets Chrysler MS-11106) has a flash Point of 254C which equates to 490F. The ASTM D4683-13 test HTHS (High Temp, High Shear rate) requires a MINIMUM temp of 150C (302F). This is the usual requirement for equipment manufacturers, so running oil temps of 257F with synthetic oils is not a problem :thumbsup: !
 
#9 ·
Many thanks to everyone who has responded. Having started with absolutely no idea what numbers I should be looking for, I now have a good range of numbers to play with. I will monitor my EVIC for both transmission and engine oil temps under various 'normal' conditions. Then monitor with the caravan hooked up, also under various conditions. I'll also make sure the transmission is using the ZF Lifeguard 8 fluid recommended. Thank you so much everyone. :)
 
#10 ·
Some metric measures for both oil and trans as follows taken recently on a few long trips etc

Normal summer driving I.E 25 to 35c oil around 97-99c @ 110km Highway speeds and trans around 90-91c

Hauling up Barrington Tops Mountain last week oil 114c and trans 95c, Jeep performed outrageously, handled the dirt rutted, corrugated and potholed roads effortlessly, thank goodness for full synthetic oils.:)
 
#13 · (Edited)
This is the problem with Jeep sharing too much info with us. They give us a "real" gauge and then we start to think that there is a problem. So we take it to the dealership, who charges Jeep for a warranty claim even though nothing was wrong. This happened with Ford trucks and their oil pressure gauges. The solution? Back in the 90s they started just putting the gauge on a on/off pressure switch. If there was more than 5 psi or something like that the gauge would always read the exact same. In other words it was no different than an idiot light really, but it fixed all of the complaints they were receiving from vehicle owners about oil pressure gauges fluctuating.

Just watch. If we keep bugging Jeep about it the oil temp gauges will just be removed on future models. Their engineers will smile and say to themselves "problem solved"
 
#15 ·
I just purchased a 2014 Overland Diesel about 10 days ago, and I'm seeing transmission temps in the 195 range in stop and go traffic and around town here in Los Angeles. What worried me is that this is the only gauge in the EVIC where the "normal" operating temp of 195-205 as some have mentioned on this thread is far past the mid-point of the gauge display. I actually emailed Chrysler to confirm the proper temp and they were useless and directed me to purchase a service manual and contact my dealer. I then spoke to my dealer service department who said that as long as I don't see a warning light it's fine, so again useless.

This thread has made me feel more comfortable about what I'm seeing, but it would be great if someone is able to confirm with Jeep/Chrysler and/or ZF that they officially expect these transmissions to run in that 200 degree range. Some ZF literature actually states that temps over 200 degrees will do irreparable damage to their transmission, so I'm still a bit nervous on this issue.

Thanks to everyone for the input though.
 
#41 ·
I just purchased a 2014 Overland Diesel about 10 days ago, and I'm seeing transmission temps in the 195 range in stop and go traffic and around town here in Los Angeles. What worried me is that this is the only gauge in the EVIC where the "normal" operating temp of 195-205 as some have mentioned on this thread is far past the mid-point of the gauge display. I actually emailed Chrysler to confirm the proper temp and they were useless and directed me to purchase a service manual and contact my dealer. I then spoke to my dealer service department who said that as long as I don't see a warning light it's fine, so again useless.



This thread has made me feel more comfortable about what I'm seeing, but it would be great if someone is able to confirm with Jeep/Chrysler and/or ZF that they officially expect these transmissions to run in that 200 degree range. Some ZF literature actually states that temps over 200 degrees will do irreparable damage to their transmission, so I'm still a bit nervous on this issue.



Thanks to everyone for the input though.

This, getting 199 on 50 deg day in stop-n-go traffic. Concerned about towing my boat next summer. If this Normal, I'll be changing trans fluid more often.
 
#16 ·
This is synthetic ATF and the transmission is designed to run a minimum of 174F which to means running well over 200F isn't an issue at all. Non synthetic transmissions would be hurting running them well over 200F. I have seen the charts showing transmission fluid life and the lower the better regarding temperature but it doesn't apply in this case. The higher oil temperatures help to increase mpgs and reduce emissions for the engine and that is the direction most manufacturers are going.
Synthetic oil which is what this LifeGuard 8 is will live to 300F by the way. So when I check mine and see it is in the mid 190's I think yep right about where it should be given a light load...
 
#18 ·
I had my first towing experience last week, so I thought I would add my experience (4x4 Limited; 3000lb trailer). The transmission temperature generally sat at 195F. I did not see it go above that. Oil temperature went up to 230F going up hill. The ambient temperature was 60F - 80F.
 
#19 ·
For reference, the highest trans temp I've seen was in snow mode creeping in horrible traffic (during the embarrassing snowmageddon experience here in Atlanta--spent 9 hours to go 15 miles including rescuing stranded people). My trans temp creeped up to 217F. Traffic was barely moving in the ice and snow for several hours. Starting in second in snow mode likely had something to do with it. Engine oil temp hovered between 226F and 235F.

The transmission temp would creep up to that max then the engine fan would come on and it would VERY quickly drop to 205-206F, fan would cycle down and it would creep up again. So, I turned on the A/C (keeping the heat on high) which kept the fan on a low cycle all the time and the trans temp then rapidly fell to 188F and stayed there.

In everyday driving mine will reach 194-197F EVENTUALLY. In stop and go with constant accelerations being used it might hit this temp and hover there after 15-20 minutes of this. On a highway trip, starting from a trans temp of 80F or so, it will take anywhere from 45-60 miles before it finally reaches 195F or so, depending on whether I have any spirited accelerations along the way.

Note: neither the trans oil temp or engine oil temps seem to be super accurate throughout the full range. When the vehicle has totally cooled to ambient (overnight or longer) my engine oil and trans temps will tend to read notably higher than ambient before startup. For example, this morning it was 39F outside and my oil and trans temps read 64F. This may be the bottom of the scale as I'm not sure if I've seen them lower, or it might be these particular sensors (same ones as the coolant temp sensor) are more inaccurate outside their center scale (pretty common for these types of sensors actually).
 
#22 ·
I had found a post once that gave the play by play state of ATF as it heated, e.g. at a certain temp it begins losing its ability to properly engage. I will try to find that again.
It doesn't really lose it's ability to "engage" so to speak. At very high temperatures, viscosity and lubricity diminish. This can effect the ability to hold hydraulic pressure on a clutch pack and can affect the ability to properly lubricate and protect moving parts.

However, the biggest issue with heat is oil breakdown. Most transmission fluids are basically engine oils base stocks with different additive packages (much more detergent, friction modifiers, etc). Most engine oils routinely see sustained temperatures over 220-260F in modern engines. They break down over time with these temps, which is one reason they need to be changed frequently (also, they get contaminated by combustion byproducts). But one needs to remember that engine oils are also exposed to much higher temps briefly which aids this breakdown process.

Older transmission fluids would start to get in trouble with sustained temps over 240F. You could calculate the fluid life based on the temperature -- at 180-190F it might last 80-100k miles but at 240F you might be down to 15-20k miles.

Modern synthetics are much more tolerant of higher operating temperatures. However, I wouldn't want to run transmission temps of 240F continuously. That said, 200F wouldn't give me any concern, or up to 220F or so as long as it wasn't sitting there all the time.
 
#21 ·
Not vouching for the gauges accuracy but the engine will hold some heat for a very long time. Having a diesel for many years now, there is a noticeable difference when you start up in the morning when it sat for 8 hours verses a day or more. This is even more pronounced when it gets down into single digits.

Put a big pot of hot soup out on your porch when it is below freezing and it is likely that the next day even the next night it might not be totally frozen. Naturally the temp and exposure to wind alters things a good bit but I have had pots of soup or sauce sit on my sun porch where the temp is in the teens and found that they were just starting to ice up nearly 24 hours later.

It is not quite as dramatic in the GC but in some of the older diesels I have owned, start up was noticeably different in the morning if I went shopping and shut the car down at 9 or 10 PM as opposed to those nights where I got home and parked it until the next day. I guess you also got feedback because you had to wait for the glow plug light to go out before you tried starting. With the GC the time for the glow plugs to heat up is that pause you get but since you are not sitting there waiting to hit the button again you really do not get a sense that one pause is much more than another.
 
#23 ·
Not vouching for the gauges accuracy but the engine will hold some heat for a very long time. Having a diesel for many years now, there is a noticeable difference when you start up in the morning when it sat for 8 hours verses a day or more. This is even more pronounced when it gets down into single digits. Put a big pot of hot soup out on your porch when it is below freezing and it is likely that the next day even the next night it might not be totally frozen. Naturally the temp and exposure to wind alters things a good bit but I have had pots of soup or sauce sit on my sun porch where the temp is in the teens and found that they were just starting to ice up nearly 24 hours later. It is not quite as dramatic in the GC but in some of the older diesels I have owned, start up was noticeably different in the morning if I went shopping and shut the car down at 9 or 10 PM as opposed to those nights where I got home and parked it until the next day. I guess you also got feedback because you had to wait for the glow plug light to go out before you tried starting. With the GC the time for the glow plugs to heat up is that pause you get but since you are not sitting there waiting to hit the button again you really do not get a sense that one pause is much more than another.
Oh I'm aware of heat soak and oil heat retention. These observations were true even with the vehicle sitting for up to 3 days.
 
#24 ·
This evening my tranny temp went to 213 while I was easing around in heavy traffic. It is rare for me to drive in those conditions. When we finally found a restaurant that wasn't packed, we parked. I could smell a burnt rubber smell and raised the hood to inspect. I saw nothing wrong. I suspect some adhesives and manufacturing too cooked off from the heat. My GC never got that hot before. I have 10,500 miles on it. Anyone else experienced this?
 
#25 ·
ZF-Lifeguard8, the fluid used in the 8HP70, has a flash point of 215 Celsius, which is 419F and a Boiling Point of >280C.

So, don't get your undies in too much of a bundle about your tranny temps in the 200 range ;).

Personally, I will change the tranny fluid and filter at 60k. But, then again, I am entirely anal LOL! .
 
#27 ·
There has been no posting here for awhile, so everyone may feel that the issue of high temps when towing up steep grades in the mountains has been pretty thoroughly explored. But I will add my recent experience to the list. We towed a 21' TT (4500 lbs fully loaded) from the Midwest to Utah out and back through Colorado three weeks ago. We too noticed the quick temperature rise as we climbed the incline to the Eisenhower tunnel, the needle going all the way to the white line next to the red zone, and the same thing happened going over the Vail pass a few miles down the road. I was really worried about what would happen when we came back over Wolf Creek Pass. But remembering that I had essentially floored it going over those two earlier passes, I decided to try just maintaining rpm's at 2000-2500, which all that is required for maximum torque. This worked great-- the engine temp still quickly increased, but the oil temp topped out at 244 and the water temp guage stopped at the halfway point in the third quarter of the guage. Speed was comfortable -- 40 to 45 mph (no faster than I wanted to be going as I started the steep descent anyway), plenty of power, and the car just cruised like it could have gone all day in that range. I had the oil changed when we returned, and the dealer said it looked fine. Mileage for the trip was excellent -- 16 mpg -- and the car pulled so effortlessly under all other conditions that I am fine living with being a litttle watchful towing over the highest mountain passes as the price to pay for all of the other benefits of this car, including its outstanding mileage when not towing.
 
#28 ·
Thanks for the update. Of course, max torque isn't max power. I think the final analysis is that the cooling system is adequate under most conditions where lower RPMs are maintained but under maximum sustained power (at higher RPMs) the cooling system may not keep up This is no different than any other standard duty vehicle. Max power for short term acceleration isn't a problem.
 
#29 ·
I've been wondering about normal temp ranges, too. I'm bringing mine to the dealer (in San Jose, CA, USA) and put this down as a question to ask the service department. If I find out, I'll report back.
 
#30 ·
Just towed today for the first time in the new Diesel.

Averaged 17 mpg towing a 4300 lb car trailer. Kept the transmission in Sport the whole time and manually shifted down to 7th for any hills or grades. Kept the rpms at 2k or above.

Trans temps stayed between 179-195.

Oil temps 221-227

Water never rose above halfway.

Speeds fluctuated between 70-80.

I'm extremely impressed.


Sent from my iPhone using JeepGarage
 
#31 ·
Just towed today for the first time in the new Diesel.

Averaged 17 mpg towing a 4300 lb car trailer. Kept the transmission in Sport the whole time and manually shifted down to 7th for any hills or grades. Kept the rpms at 2k or above.

Trans temps stayed between 179-195.

Oil temps 221-227

Water never rose above halfway.

Speeds fluctuated between 70-80.

I'm extremely impressed.
You have the correct approach to towing IMHO. Lugging the engine heats up the tranny from excessive continuous torque. Sport mode shifts later to avoid this, as does your manual downshift in grades. 2k rpm has been documented by many to keep water/oil temps in check.
 
#33 ·
So, yeah, when I dropped off my 2014 JGC EcoDiesel at my dealership yesterday morning for a fix, I brought my list of questions to ask. (The fix, BTW, is for the fuel filler door flap that wasn't aligned well when I bought my Jeep. They had to order the arm for that, and they're installing it.)

As for normal operating temp ranges for oil and tranny, I asked the service tech guy. He searched their internsl tech talk system for it (internal-to-Jeep dealers service personnel) but wasn't able to find anything... yet. He wants to keep searching, so hopefully we'll have an answer from him soon.
 
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