Transmission oil temperature.

Aus-Kiwi · Guru

Transmission oil temperature.

iana · Guru

Yes and thanks Aus-Kiwi, I've been doing maintenance since god knows when, the term "service" is such a rubber word, my training was doing inspections, I guess the service was incorporated in that.

I have doing a bit of reading about transmission cooling, and have reached the following conclusion, that the Australian sellers of transmission oil cooler kits are doing a bit of scare mongering, and I wonder what if any research has gone into it.

That the standard coolant radiator has more than enough capacity to cool the motor, but that could be off-set by insects and air restrictions.
That liquid to liquid cooling is far more efficient than liquid to air.
That bringing the transmission "up to temperature quickly" is also very important for the health of the transmission, stating dont do away with the coolant heating when fitting an assessory cooler.

Been trying to figure out how the auto gearbox modes work, now I was told by a so-called expert, that the "S" mode activates the torque converter lock, but according to the Mazda and Ford speele, all it does is modify the point at which the gears change, i.e. in "S" mod they change earlier, and hang in gear for longer, i.e. to assist in braking. So how to activate the torque converter lock. Yesterday we had a long climb fully loaded over some rangers, and I used manual most of the way. The max temperature reached was 101 degrees. So quite an improvement. So the converter slipping must be making the extra heat.

My only complaint with using manual, was that I had to shift either up or down to take it out of auto. It would be much better to have a button to shift the system into manual, and at the same time holding that gear. But by using manual gears, the transmission runs cooler, and may stay in the safe range without having to modify the vehicle.

Anyway still exploring but not rushing into anything.

Jaahn · Guru

Hi Iana smile

My thoughts on the subject. I do believe also that the " Australian sellers of transmission oil cooler kits are doing a bit of scare mongering" and whats more they use ideas from past years to justify some of it ! What is also true is that autos have had liquid to liquid heat exchangers almost since they were made ! People seem to have ignored this even on here. confuse Why else do those pipes run to the radiator tanks ? You know the ones they use to fit the air cooled heat exchanger.

In our climate the startup heating of the oil in the transmission is not so important but is designed in. The hot end of the operating spectrum is certainly important here and more so if towing generally. I doubt that the 'world manufacturers' consider our small towing market as very significant, so would not design in much allowance for that.

It is true that the general operation of the transmission generates minimal heat. The important heat generation comes from the torque converter slip. Years back they put in the lockup clutch and solved this problem for a couple of years, and the fuel use dropped to prove it. However since then they started to slip the lockup clutch to smooth the changes and to avoid dropping back a gear. WHY because they can !!! Makes the drive "feel better" to the average punter. Having 3T hanging on the back is not in the equation IMHO.

The modes for the auto gearbox to operate would be a mystery that only the engineers know. But you are investigating them in your situation. Every function and operation is under the control of the computer so they can do any silly thing if they choose. The lockup kits people pay to fit are only just reversing what the engineers designed in. Might be worth it if they work. But you might have found that the M mode does the same for no expenditure smile sounds good to me. The recommendation to tow in S mode might also enable some other useful features too that you do not know about. I guess if you can monitor the revs accurately you can see if the converter is unlocked or not. I believe the gearbox input is also monitored for revs and may be available with the right program also.

Jaahn

PS I see that Scangauge 11 for a Mazda BT50 has this as an X-gauge ; Transmission Slip Ratio TSR. I believe that is the torque converter slip.

-- Edited by Jaahn on Sunday 6th of January 2019 11:52:14 AM

-- Edited by Jaahn on Sunday 6th of January 2019 02:39:49 PM

Eddo · Newbie

Good discussion - just learning my through the BT50 auto's weaker points. How may here have actually had the standard cooler bypassed to run an aftermarket cooler? Anyone here actually had the factory cooler fail and contaminate the auto with coolant?

iana · Guru

Hi Eddo, I'll have to read this thread again to refresh, but I can tell you when I was looking into oil coolers, and spoken to transmission persons trying to sell them. Not one had seen a factory fitted oil cooler fail, and of course they couldn't produce one as an example, would have made a good sales pitch.
We have done a circuit of Aus, in some extreme temperature, towing an over weight set up. I can tell you that transmission oil temperature is directly related to the weight of the right foot. we had our oil changed before we set out, and the vehicle serviced when we got back, the oil sample was good to go for another term.
The first thing you need to fit is a scan gauge. We drove according to the scan gauge temperature, it is surprising just how much the oil temperature will climb when just driving a bit faster. Steep climbs we dropped into manual. So far all is still good.

Eddo · Newbie

Hi Iana.
I have a scan gauge. Dont tow anything heavy just a little camper about 1000kg. Have not seen temp over 100 so far but have only done a few hundred km in it. Has 92000k on it. I have it booked in for its first trans service. It is a car I plan to keep for 10 years. I have been quoted $1500 for the service plus after market cooler plus bypass valve mod. Maybe it is sufficient to to just get the trans serviced and ATF changed every year or 40000? It will also be used for semi serious off roading - but I dont think that that will produce high ATF temps as in low range it is usually fully locked up ie no or little slip.

Eddo · Newbie

Hi- who do you get your oil sampled by? thanks

Ian G · Senior Member

I have an MUX, the first decent trip I did from Melb to Qld via Tamworth, my Auto Trans over temp light came on, as soon as I got home I fitted a scangauge and cooler from wholesale automatics, now my transmission temp always sits about 10 deg below coolant temp, rarely over 90 deg., took about 2 hrs to fit it, just do it, best $500 I have spent on my car

iana · Guru

During the standard service, they should take a sample and examine it. They will then let you know the results. If not you should ask for it. The transmission oil is changed on condition, so don't fret about it. I take it you have the standard 4 door ute with a well body.

iana · Guru

Just re-read this thread, a project I was embarking on a while age. Had trouble getting approval from the accounts department, so haven't done it yet.
One interesting point is that I have not yet found the correct operating temperatures for "full synthetic" transmission oil. The temperature quoted read as though they relate to standard mineral oil. Synthetic oils can operate at much lower and much higher temperatures, and I am certain the seals and other components in the system have been designed to cope with that. For example the thermostatic valve that by-passes the cooler begins to open at 90 degrees, so the oil cooler does not begin to function until the oil reaches 100.
I am not against the idea of fitting an oil cooler, but I'm sure that the temperatures in the higher bracket are OK.
As you have read, I have an extra cab tray top ute, I was exploring the idea of fitting a cooler on the rear side of the ute near where the petrol filler is, one of the reasons was to get the expelled heat away from the other radiators that also have a job to do.
I found that the temperatures rose when traveling in slow traffic when towing, the electric fan cutting in would add useful cooling for that circumstance.

Warren-Pat_01 · Guru

Hi ian,
If you have any concerns, have a look at this link www.colvoss.com.au/blog/2019/12/7/automatic-transmission-operating-fluid-temperatures.

I put a Scangauge on early last year & saw my transmission get to 115 degrees on a wet day near Proserpine last year - towing the van home. Of course, my dealer who is in business of selling cars, parts (major & minor) said "That's ok - you have no problems, the transmission will cater for that ok." That's not what this chart says! And I believe the Isuzu transmission alarm comes on at 130 degrees!

Since adding the cooler, I have only seen the transmission temperature equal the coolant temp (90 degrees) once - generally the transmission is 10-15 degrees cooler than the coolant - bearing in mind that I live in the tropics. And as my car is still under the manufacturer's warranty, I asked the dealer whether they'd fit the cooler. I can still see the service assistant's face (LOL). At that stage the car had done 40,000kms & I asked the mechanic who installer the Wholesale Automatics cooler to keep me some oil out of the transmission when they did the service. It was a very dark, almost black maroon colour. They said it was ok but it's out now.

If I get into the very cold temperatures in southern Victoria, etc, I'll add a cover to the cooler.

Mike Harding · Guru

My Holden Trailblazer had a dash readout of the auto fluid temperature; the highest I have seen it is 95C, if it ever touched 100C I would stop and wait for it to cool.

oldbloke · Guru

I believe using "sport" mode helps. I use it most of the time when towing with my 4 speed MN Triton. Seem to get better economy and engine sou d's happier. But TBH I'm not sure exactly how it all works, nor what it does.

Allows me to stay in a selected gear, got no idea if it effects the torque converter.
Googled it, read the manual and it is still a mystery to me. Lol

Is there any info out there?

oldbloke · Guru

Double post

-- Edited by oldbloke on Wednesday 2nd of February 2022 05:06:53 PM

Warren-Pat_01 · Guru

Mike, that was the main reason I added the cooler otherwise I wouldn't get anywhere & I guess the reason why you southerners head south in September, October leaving us in "sweaty paradise". 90 to 100 & a few times to 110 degrees was commonplace. I hate to think how it performed before adding the gauge & relying on dealers! And when I found that blog, it was mind blowing.

The $850 for the cooler & service was expensive but at least now I'm protected for a good while.

iana · Guru

It wasn't me that brought up this old post, it was Eddo!
But for the X-Spurts out there, show me the info on transmission operating temperatures for those running on full synthetic oil. Love to read about it.

iana · Guru

Having had another search on the web, unable to find any data relating to operating temperatures of synthetic transmission oil. However I notice that the different companies quote a "Kinematic Viscosity @ 100C" test, so I am going to assume that 100 degrees C is a normal operating parameter. Wrong, 100 degrees is just the benchmark for this test and is applied to all oils, so still none the wiser.

-- Edited by iana on Wednesday 2nd of February 2022 08:02:33 PM

Code4 · Member

I recently fitted a popular brand Auto transmission oil cooler on my 2015 Colorado auto.
In ambient temperatures of 30 deg C+ it provided 14% cooler oil. AT approx 20 deg C it was 25% cooler oil. This was unloaded and around town.

Aus-Kiwi · Guru

Keep in mind the coolant temp is not much under what the auto should run at !!

iana · Guru

Aus-Kiwi wrote:
Keep in mind the coolant temp is not much under what the auto should run at !!

I agree, the problem arises when the heat produced by the transmission is more than the plate heat exchanger can cope with, bearing in mind the small temperature differential. Wet heat exchangers are way more efficient than wet to air, but they do need a temperature differential to work well.

swamp · Senior Member

hi
All oil degrades syn or mineral just synthetic a little slower . This always happens at 100C or greater . Reference Valvoline and other majors .
Since engines and transmissions have been made high running temps have been tried ,nothing good comes from it . Always results in more expensive repairs in industry and for auto industry .
First determine your vehicle is actually o/heating anything over a 100c for how long ???
Long term damage is caused to engines and transmissions are no different .

Seen synthetics used in hydraulics to reduce temps ...fail .. done at manufacturer
Seen engine and trans sump reduced capacity to fit chassis ... fail ... done at manufacturer
Seen many radiators changed at dealer b4 delivery in ozzy

Engines and trans that run at 80-90 will have more reusable parts at o/haul compared to cooked engine/trans that run at 100cel

Have the Ranger/BT double coolers fitted together with the internal by pass also if towing a big van. Speak to Auto specialist Rowell and Searlle in Adelaide [very experienced 50yrs plus ].

Just had a custom racing tube style construction with internal cooler . Internal cooler is great wet to wet but not enough space inside rad tank most of the time . In this case a small plate /fin will also be used .

-- Edited by swamp on Tuesday 8th of February 2022 12:51:43 AM

Eddo · Newbie

I have had a cooler ( and bypass valve) fitted at same time as transmission got its first service ( 90000km)
According to the bloke who did it - the oil was dark in color but did not stink of being seriously overheated.
So hopefully this transmission will last for my 10 year and 200000km plan for the vehicle ( 2017 BT50).
It is immediately obvious that trans now runs around 80 rather than 95-100 in normal driving.
I will feel much more confident when in extreme conditions now that this is done - and that is important to me from a driving enjoyment pov.
Next job - change all the other oils.

KJB · Guru

swamp wrote:
hi
All oil degrades syn or mineral just synthetic a little slower . This always happens at 100C or greater . Reference Valvoline and other majors .
Since engines and transmissions have been made high running temps have been tried ,nothing good comes from it . Always results in more expensive repairs in industry and for auto industry .
First determine your vehicle is actually o/heating anything over a 100c for how long ???
Long term damage is caused to engines and transmissions are no different .

Seen synthetics used in hydraulics to reduce temps ...fail .. done at manufacturer
Seen engine and trans sump reduced capacity to fit chassis ... fail ... done at manufacturer
Seen many radiators changed at dealer b4 delivery in ozzy

Engines and trans that run at 80-90 will have more reusable parts at o/haul compared to cooked engine/trans that run at 100cel

Have the Ranger/BT double coolers fitted together with the internal by pass also if towing a big van. Speak to Auto specialist Rowell and Searlle in Adelaide [very experienced 50yrs plus ].
Just had a custom racing tube style construction with internal cooler . Internal cooler is great wet to wet but not enough space inside rad tank most of the time . In this case a small plate /fin will also be used .

-- Edited by swamp on Tuesday 8th of February 2022 12:51:43 AM

Seems to me that Manufacturers are more intent on promoting how little fuel their vehicles use rather than the overall cost of ownership .....

Aus-Kiwi · Guru

Yes plus mainly set up to last to warranty ! Only !!

Jaahn · Guru

iana wrote:
Having had another search on the web, unable to find any data relating to operating temperatures of synthetic transmission oil. However I notice that the different companies quote a "Kinematic Viscosity @ 100C" test, so I am going to assume that 100 degrees C is a normal operating parameter. Wrong, 100 degrees is just the benchmark for this test and is applied to all oils, so still none the wiser.

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Hi iana smile

Have you looked at this site ? A lot of stuff but you might need to scratch around to find it, or ask your question there.

https://bobistheoilguy.com/forums/forums/atf-differential-trans-brakes-p-s.16/

Jaahn

swamp · Senior Member

hi
Industrial aircooled v twins .
Some companies are that bad, redesigns are happening all the time to reduce heat effects .

Engine block distortion showed up as leaking gaskets and high sump temps
Better head gaskets
head studs not bolts
cast alloy valve covers vs plastic style
inlet manifolds larger studs better gaskets
cooling holes to give access to blow dust out

These fixes all helped to get outta warranty BUT did not make the problem go away
Sump temp under high acceptable load at high ambient temp 113--117 odd times 120 cel

Fitted 12 x 12 x 1.5 inch cooler with electric fan with oil filter tripled in size . An oil thermostat of 80 cel

....Operating now 90 --100cel all loads all ambient temps
No engine problems

One of many cooling problems I have solved .

KJB · Guru

swamp wrote:
hi
Industrial aircooled v twins .
Some companies are that bad, redesigns are happening all the time to reduce heat effects .

Engine block distortion showed up as leaking gaskets and high sump temps
Better head gaskets
head studs not bolts
cast alloy valve covers vs plastic style
inlet manifolds larger studs better gaskets
cooling holes to give access to blow dust out

These fixes all helped to get outta warranty BUT did not make the problem go away
Sump temp under high acceptable load at high ambient temp 113--117 odd times 120 cel

Fitted 12 x 12 x 1.5 inch cooler with electric fan with oil filter tripled in size . An oil thermostat of 80 cel

....Operating now 90 --100cel all loads all ambient temps
No engine problems

One of many cooling problems I have solved .

That is the go....do not just replace with more of the same , get to the bottom of the problem. Nice fix.........KB

swamp · Senior Member

hi
Oh yea synthetic oil did not solve anything either as it was over worked & running at high temps . Sump Oil capacity was to small and with the added cooler /filter capacity 1.5--2ltrs the oil at service would drain and be in far better condition .

Then had to asses the dirty intake environment , this was partially corrected . The undersize Donaldson twin stage filtration needed to be upgraded to bigger size even thou it had a precleaner .

The air was so dirty a third filter was fitted ,an oil soaked foam unit . The dust was so fine it would discolour the filter oil. Previously the fine dust would end up in the sump oil . Moral of the story this all helped the sump oil have a happy happy life .
Clean oil at service running at correct operating temp .....

Aus-Kiwi · Guru

Keep in mind the fluid is only taking the heat from mechanical parts ! Its these parts that break down INTO the fluid . If theres any there ? Its too late ! Some damage is done !

swamp · Senior Member

hi
Remember some aftermarket companies sell coolers that are way large
230 mm H
560 mm long
32mm thick
Made by Long industries [DANA Corp] This brand does millions of factory fitted coolers
Retail is Tru Cool . Most resold coolers in ozzy are made by them rebranded .
Common size for

Dodge Ram 1500 2500 3500 , Duramax and F trucks 250--350-450

Now that might size might fix a Ranger . Then again if u don`t tow with it LOL..

-- Edited by swamp on Tuesday 15th of February 2022 01:33:10 AM