Nitro 4.88 gear heat

[linuxgod]

Everything about this seems odd. I think I would set aside the changes you made and focus first on why the engine and transmission temps would be running higher but not the coolant. That seems like the best place to start. From there work back towards possible root causes?

In an immediate reversal of my thinking, it seems like tires could change the load on the drivetrain, so I suppose that could be a source.

Me guessing about things I don't fully understand isn't going to help, so I'm just going to hang out and watch you and Rob figure it out because I agree that understanding the change is the only option. Ignorance is NOT bliss. My problem is that if I were encountering this situation with my truck, I'd be tagging you, Rob and @TeCKis300 for help so...

Agreed. The only commonalities I've come up with though are (a) they're all near each other and thus some sort of radiant heat impact, or (b) they all tie into the cooling system in one way or another. "B" seems more likely but then why does the coolant temp remain steady while transmission and engine oil temp increase?

Anyone have a good diagram of the complete cooling system? If it's "B", then my hunch is that the A/T cooler get the fluid below temp (I've not measured but let's say "180F" for the sake or argument) but the radiator is getting it back up to temp and then some (210F) and sending that back to the pan. I know from the diagrams that the coolant temp sensor is actually near the top of the radiator (I'm assuming near the thermostat?), but I can't find where the other temp sensors (oil, AT TC, AT pan) are located. I also can't tell where in the coolant flow it gets diverted to the engine oil cooler and back.

 

[linuxgod]

Looking at the diagrams above, what is the cooler compressor assembly? Is that for the A/C? Asking because in examining the truck closely I noticed what appears to be an oil leak. I can't tell if it's a slight valve cover drip that's getting sprayed or something else, but the cooler compressor (behind the pulley) had some oil on it both top and bottom that looks recent.

Name that leak

Valve cover gasket? Seems odd if it is that the gasket leaked across the engine bay, unless the fan is spraying it all over the place. Engine oil is full, but there's definitely residue on the lower part of the engine that looks suspiciously like oil I noticed this when checking the truck...

forum.ih8mud.com

I wiped it up as best I could with a shop rag in the garage this morning (no engine degreaser handy) so I'll see if it persists or if this is a case of "last oil change monkey spilled oil on the front of the engine".

 

[ttrmike]

Looking at the diagrams above, what is the cooler compressor assembly? Is that for the A/C? Asking because in examining the truck closely I noticed what appears to be an oil leak. I can't tell if it's a slight valve cover drip that's getting sprayed or something else, but the cooler compressor (behind the pulley) had some oil on it both top and bottom that looks recent.

Name that leak

Valve cover gasket? Seems odd if it is that the gasket leaked across the engine bay, unless the fan is spraying it all over the place. Engine oil is full, but there's definitely residue on the lower part of the engine that looks suspiciously like oil I noticed this when checking the truck...

forum.ih8mud.com

I wiped it up as best I could with a shop rag in the garage this morning (no engine degreaser handy) so I'll see if it persists or if this is a case of "last oil change monkey spilled oil on the front of the engine".

That would be the AC Compressor. The system is full of refrigerant and a small amount of oil, so i think a valve cover/cam tower leak or oil change spill more likely.

 

[Moby]

My thought would be the same as @TeCKis300's #3. While I don't see how the heat would radiate did you break the gears in without towing? And then again while towing? I don't tow but the instructions I've always had for gear changes is two break in steps. Toyota even lists this in the owner's manual (I haven't checked for the LC but they were still specifying this for my GX when it was new). It's a long shot but my only thought on this being a gear related problem

 

[linuxgod]

My thought would be the same as @TeCKis300's #3. While I don't see how the heat would radiate did you break the gears in without towing? And then again while towing? I don't tow but the instructions I've always had for gear changes is two break in steps. Toyota even lists this in the owner's manual (I haven't checked for the LC but they were still specifying this for my GX when it was new). It's a long shot but my only thought on this being a gear related problem

Yeah I followed the Nitro break-in procedure to a T. 15 miles then cool down. Did that twice. Then the remaining 500 miles being very gentle on the gears and always keeping below 55mph (and the majority of driving was city or suburbs). Once I hit the 500 mile mark I did three consecutive 15 mile trips with the trailer in tow, letting it cool down for 30 minutes between trips. Right after that I did the fluid change.

 

[bloc]

The vast majority of people with trucks/SUVs don’t follow proper break in procedures and never have issues. I just don’t see how gears can add that much drag to cause an increase in trans temps.. while sounding and acting healthy. or as everyone has been trying to figure out, increase oil temp at the same water temp.

I’m inclined to think this is simply a function of increased RPMs in each powertrain assembly.

I’d be curious whether sustained cruising unloaded could trigger a similar response. HP demands and total load would be way down..


Also something I forgot to say earlier. The ATF heat exchanger in the radiator is also there for cooling, not just warming the fluid lore quickly. If you are adding enough heat to the fluid that the air/fluid exchanger can’t get the job done, such as times with low airflow, the one in the radiator has a tremendous ability to transfer heat into the coolant and use that large radiator and fan to keep temps in check. IMO this adds a potential dynamic because while water temp in the block hasn’t changed, that doesn’t mean water in the radiator is the same temperature. The thermostat keeps the block at a given temp but the fluid flowing out of the rad can be a very broad range of temps depending on ambient temp, speed, what the fan is doing etc. The heat exchanger down there doesn’t have the same regulating system as the engine thermostat.

 

[linuxgod]

The vast majority of people with trucks/SUVs don’t follow proper break in procedures and never have issues. I just don’t see how gears can add that much drag to cause an increase in trans temps.. while sounding and acting healthy. or as everyone has been trying to figure out, increase oil temp at the same water temp.

I’m inclined to think this is simply a function of increased RPMs in each powertrain assembly.

I’d be curious whether sustained cruising unloaded could trigger a similar response. HP demands and total load would be way down..


Also something I forgot to say earlier. The ATF heat exchanger in the radiator is also there for cooling, not just warming the fluid lore quickly. If you are adding enough heat to the fluid that the air/fluid exchanger can’t get the job done, such as times with low airflow, the one in the radiator has a tremendous ability to transfer heat into the coolant and use that large radiator and fan to keep temps in check. IMO this adds a potential dynamic because while water temp in the block hasn’t changed, that doesn’t mean water in the radiator is the same temperature. The thermostat keeps the block at a given temp but the fluid flowing out of the rad can be a very broad range of temps depending on ambient temp, speed, what the fan is doing etc. The heat exchanger down there doesn’t have the same regulating system as the engine thermostat.

I don't think it's increased RPMs though. I used to run ~3100 RPMs in 4th gear at 75 mph. Now I run either 2700 in 5th gear or 3600 in 4th. In both scenarios the temps were 210F @ 75MPH. In all scenarios the torque converter is locked. So more or less RPMs doesn't matter now the temps are always hotter.

Starting to consider the radiator warmer/cooler as well in this. I need to go look at the radiator flow pattern - is it hot water coming in at the top and cold water flowing out at the bottom, or vice-versa?

 

[TeCKis300]

I think many would be surprised by the drag introduced by higher viscosity oils. Viscosity after all, is the measure of resistance to flow. With increasing force generally the square of speed. It's logical that additional force (HP) is required to move higher viscosity oils, compounded by speed.

I'm sure most have heard that higher viscosity engine oils can reduce measurable HP. I notice a ~.5MPG difference running 0W-30 vs factory 0W-20. Equivalent to saying the engine is producing increased HP that is lost to efficiency as thermal energy moving oil. Think shocks resistance to motion and converting it into heat.

It's no different than the driveline. And is why OEMs chase lower and lower viscosity oils. Including the later spec'd 75W for the transfer case. In this case, diff oils went from hot viscosity of 90 to 140 weight. That's a not so small change.

I chalk it up to the engine and transmission handling more HP, and increasing oil temps, for the 3 reasons I stated. I know the diff is broken in, but that still doesn't mean it's not tighter as a relatively fresh build.

 

[linuxgod]

I think many would be surprised by the drag introduced by higher viscosity oils. Viscosity after all, is the measure of resistance to flow. With increasing force generally the square of speed. It's logical that additional force (HP) is required to move higher viscosity oils, compounded by speed.

I'm sure most have heard that higher viscosity engine oils can reduce measurable HP. I notice a ~.5MPG difference running 0W-30 vs factory 0W-20. Equivalent to saying the engine is producing increased HP that is lost to efficiency as thermal energy moving oil. Think shocks resistance to motion and converting it into heat.

It's no different than the driveline. And is why OEMs chase lower and lower viscosity oils. Including the later spec'd 75W for the transfer case. In this case, diff oils went from hot viscosity of 90 to 140 weight. That's a not so small change.

I chalk it up to the engine and transmission handling more HP, and increasing oil temps, for the 3 reasons I stated. I know the diff is broken in, but that still doesn't mean it's not tighter as a relatively fresh build.

Ok I’m taking that to mean your vote is swap out the diff fluid for 75W90.

 

[TeCKis300]

Ok I’m taking that to mean your vote is swap out the diff fluid for 75W90.

I'm just postulating the why. I do believe it'll reduce the operating temps in the engine and tranny a bit, but may not be fully back to your baseline with some of the variables others have suggested.

At the same time, I don't think you're really hurting anything. Similar to the reasons I choose to run incrementally higher viscosity engine oils for heavy towing with minor trades to efficiency.

Interestingly when I installed my Harrop e-locker, it was recommended not to use overly heavy oils as it has the potential to actuate the locker with higher hydraulic forces.

 

[grinchy]

Here's my temperatures on 4.88s that have around 15k miles on them, running 75w-140 Amsoil Extreme. This is after a 20 mile hwy run with 10 min of city on either side, followed by 2 hr cool down, about 15 hwy miles into the return trip. I've noted the maxes. Temps for all three seem to run pretty fluidly in a 5-10 degree range, but the spread between the three is usually around 15 deg.
Torque, LX570, Vgate ble 4 OBDII
Using @linuxgod dashboard (had to relink the sensor PIDs, no conversion changes made)

Unladen, rolling hills, all measurements in 6th, NOT towing
Ambient - 70 deg - 65mph on GPS. Cruise engaged.
Radiator Temp - 195F
Transmission #1 - 205F
Transmission #2 - 210F
Oil Coolant - Not reported (still looking for this PID to relink)

Not sure if that helps . . .

Saw the same temps in the 10 min city stop and go post highway as well.

 

[TLC2013]

Here's my temperatures on 4.88s that have around 15k miles on them, running 75w-140 Amsoil Extreme. This is after a 20 mile hwy run with 10 min of city on either side, followed by 2 hr cool down, about 15 hwy miles into the return trip. I've noted the maxes. Temps for all three seem to run pretty fluidly in a 5-10 degree range, but the spread between the three is usually around 15 deg.
Torque, LX570, Vgate ble 4 OBDII
Using @linuxgod dashboard (had to relink the sensor PIDs, no conversion changes made)

Unladen, rolling hills, all measurements in 6th, NOT towing
Ambient - 70 deg - 65mph on GPS. Cruise engaged.
Radiator Temp - 195F
Transmission #1 - 205F
Transmission #2 - 210F
Oil Coolant - Not reported (still looking for this PID to relink)

Not sure if that helps . . .

Saw the same temps in the 10 min city stop and go post highway as well.

Good stuff. Going to compare these to my stock gearing temps for the heck of it. What ATF fluid are you running and did you switch to 5-30 oil or still running the 0-20? If i remember correctly my trans temps were hovering just below 200 with amsoil SS ATF and redline d6 mixture. ill double check with my OBD fusion app later this week.

 

[grinchy]

Good stuff. Going to compare these to my stock gearing temps for the heck of it. What ATF fluid are you running and did you switch to 5-30 oil or still running the 0-20? If i remember correctly my trans temps were hovering just below 200 with amsoil SS ATF and redline d6 mixture. ill double check with my OBD fusion app later this week.

I have unknown Transmission fluid at the moment. I"m going to do a drain/fill/cycle with 9 qts in the next couple weekends, using bog standard Valvoline Full Syn multi-vehicle.
Running 0w-30 full syn motor oil.

 

[TLC2013]

I have unknown Transmission fluid at the moment. I"m going to do a drain/fill/cycle with 9 qts in the next couple weekends, using bog standard Valvoline Full Syn multi-vehicle.
Running 0w-30 full syn motor oil.

Last week i did the full fluid exchange noticed it took over 10 qrts to really see a significant change in the fluid color. 13 qrts should have done it but I ended up loosing more old fluid then I should have out of the return drain line from the cooler. I cycled out around 2 quarts each round after draining and filling the pan with fresh fluid. Went through about 15 qrts somehow but ended up with brand new looking fluid.

 

[grinchy]

Good info. I’ll grab another gallon.

 

[linuxgod]

Thanks @grinchy. I have oil temp in OBD Fusion as a stock Toyota PID. I’ll see if I can figure out what it looks like for ya

fwiw I swapped from 75W-140 to 75W-90 last week and then went camping over the weekend and there’s zero difference in my temps. Give your trans temp is a bit higher than mine used to be I am thinking the gears create some extra drag that’s increasing temps a bit.

 

[grinchy]

Thanks @grinchy. I have oil temp in OBD Fusion as a stock Toyota PID. I’ll see if I can figure out what it looks like for ya

fwiw I swapped from 75W-140 to 75W-90 last week and then went camping over the weekend and there’s zero difference in my temps. Give your trans temp is a bit higher than mine used to be I am thinking the gears create some extra drag that’s increasing temps a bit.

The one I have linked is in the SAE PId section

 

[linuxgod]

In OBD Fusion, the Engine oil temp is under "Toyota, Lexus, Scion" -> "Engine & Electronic Controlled Transmission" -> "Engine Oil Temperature". Same area as the A/T temps (once you're in the "Engine & ECT" section just search for "oil". It's not an SAE PID.

 

[linuxgod]

Good info. I’ll grab another gallon.

Yeah IIRC the transmission holds a bit over 12 quarts.

 

[grinchy]

In OBD Fusion, the Engine oil temp is under "Toyota, Lexus, Scion" -> "Engine & Electronic Controlled Transmission" -> "Engine Oil Temperature". Same area as the A/T temps (once you're in the "Engine & ECT" section just search for "oil". It's not an SAE PID.

I guess my 2009LX doesn't have an Engine Oil Temperature sensor or PID. Section doesn't have it and 'oil' search doesn't return a match. Looked in the other sections as well.