Ford Ranger and Mazda BT50 Transmission cooling system.

iana · Guru

Ford Ranger and Mazda BT50 Transmission cooling system.

Jaahn · Guru

Hi Iana smile

Auto transmissions have always used an oil to water cooler that was either in the radiator lower tank or in later years a seperate heat exchanger. There has been no change in principle for 50 years. People now just notice more of the details because of the problems driving a 4-5 ton rig.

It was always recommended that you by-pass the cooler in the radiator and fit a seperate air cooler in front of the radiator to keep the temp down towing. However with the heat exchanger on the transmission there are no external transmission oil lines handy to use for this. But an adaptor could be found I am sure aftermarket.

I suggest that the new ECU controlled transmissions do get the cooling and heating of the transmission oil monitored and the flow through the heat exchanger is controlled to 'optimise' the temperature as far as possible. Also having a lock-up torque converter will put far less heat into the oil. All transmissions now have this feature but for drivability they do not always lock it fully like they did 10-15 years ago, but aftermarket kits can 'fix' that.

Jaahn

-- Edited by Jaahn on Tuesday 18th of February 2020 09:20:04 AM

-- Edited by Jaahn on Tuesday 18th of February 2020 09:22:41 AM

Greg 1 · Guru

As Jaahn has said, the modern computer controlled transmissions like to control the temperatures within a given range. This includes being too cold. By running this type of exchanger, which are quite efficient, it is much easier for the computer to do that. In some cases, it is beneficial to fit a larger cooler system, but usually these are recommended in the owners manual if required when towing. To better the oil to water exchanger with an oil to air type the later needs to be of significantly larger size. If it is not recommended by the manufacturer you probably don't need to fit one. Most of the older automatics benefited by the fitment of an after market cooler and were often recommended by the manufacturers. This has become a bit of a myth that the moment you hang a van on the back you need a cooler. It is still the case with some vehicles but others not. I have seen similar stories when it comes to radiators. That is if I fit a $800.00 aluminum radiator it must be better. What is forgotten is that aluminum is about 15% less thermally efficient than the equivalent brass or copper radiator core so unless you increase the size of the aluminum radiator you are better off with the copper or brass unit. Seen some horrible results in race cars from the go fast aluminium radiator syndrome.

iana · Guru

Thanks for those replies, its good to see replies that can think outside the square. The engine coolant radiator is apparently over sized, and should be able to handle the cooling of the transmission as well, providing the outside temperatures are low. It all comes un suck in the Aussie summer though.
We have the scan gauge fitted and can monitor the transmission temperature, adjusting speed drops the temperature, but it is still averaging 106', and can go up to 110' on the hills, or in slow city traffic.
I have a problem with fitting a cooler at the front of the vehicle, as it is releasing heat in front of the inter-cooler, air con and engine radiator. I would have thought sending hotter air into the inter cooler on a hot day was not a good formula.
But fitting a transmission cooler rearwards with an electric fan would be the way to go, bit like Hino trucks. This would over come slow travelling in traffic, or when one is stuck behind a truck in the hills, both of which cause the temperatures to rise.

Wanda · Guru

Iana, fitting a cooler in front of the BT 50 poses no problems, and you will see a significant drop in your temps.
Ours, like yours especialy when towing was in the 110+ range(higher on steep rises), now with cooler fitted(removed the water cooled one completely) it consistently remains in the low 90s. No brainer
Ian

Greg 1 · Guru

Have you checked what the design operating temperature range for the BT50 transmission is? Modern autos like to operate within an optimum range. Racing off and bolting a cooler on it without knowing what the effect of that might be can be just as harmful as overheating. The after market boys will always push their products. It is wise to do some investigation into the end results before taking a leap of faith.

iana · Guru

Thankyou Greg, I was hoping to have "round robin" discussion on the matter, rather than just being "told" what to do. The designers of these systems can't be idiots, so must have reasons for the installation. I like to understand how and why a system works before jumping in with modifications.
Higher temperatures with the synthetic oils must be a design feature, as the oil will always be higher than the engine coolant, also the thermo-bypass valve is there to bring the oil up to temperature quickly. The rage is now to remove this valve.
I suspect the normal operating temperature is between 100-106.

outlaw40 · Guru

I think the main problem is that these vehicles are not designed for Australian conditions . More suited to north America. The designers aren't perfect, even back in the 80s the manufacturers advised fitting a transmission cooler if towing . 99% sure it was in the ford owners manual under towing . They are yet to make the perfect vehicle capable of performing in all conditions without some alteration .

Greg 1 · Guru

I am not saying not to fit a cooler. Just that on some vehicles it is not necessary and at times some of these after market bolt ons can do more harm than good depending on the transmission. So do some homework before jumping in just because the corner store selling coolers says it's a good idea. Transmissions have moved on a long way since the 1980's so references to that era are not applicable to transmissions today. Back then most manufacturers recommended an additional cooler if towing. Today some do and some don't. Check with the vehicle manufacturer first.

Aus-Kiwi · Guru

Tow in lower gear also ? Meaning if your driving into headwind or up a slight elevation . Cruising along at 1200 rpm or so could be a little tough on engine . The turbo is working hard even though you think engine is doing fine !! This can generate untold heat. The ECU doesnt know your towing near its max . As some say to put trans in sport mode . Or just manually pull it down a gear or two . If it doesnt do it itself ? Higher rpm and lighter throttle is easier on motor, trans . Better fuel consumption too ! Make sure the oil cooler lines are large . Ive used engine coolers for that same reason on another application . Its correct vehicles are build better in this area ! But sheesh we are pushing them !! Power is way higher than the 4.2 older 6 cyl diesels . With 4 cyl at near half the capacity !!

Jaahn · Guru

Hi Iana smile

After a bit of research it seems that the transmission in the Ranger and BT50 is fitted in some variations to rather a lot of vehicles. "individually tailored" to each application I am sure the manufacturers would say. hmm

Started Life as a ZF 6HP26 and now both Ford and GM make them under licence, and others, in various countries for a big range of vehicles and sizes. So what does that mean. Who knows ??

I will see if I can find some more information about the fluid and temperatures and cooling.

Jaahn. some light reading ! aww

https://en.wikipedia.org/wiki/Mazda_BT-50

https://en.wikipedia.org/wiki/Ford_Ranger_(T6)

https://en.wikipedia.org/wiki/Ford_6R_transmission

https://en.wikipedia.org/wiki/ZF_6HP_transmission#6HP26

https://en.wikipedia.org/wiki/GM_6L80_transmission

http://www.cadillacfaq.com/stsfaq/tsb/data/tsb/05-07-30-023.pdf

Greg 1 · Guru

Doing a little bit of research, the thermostat in the Ranger BT50 transmission opens to the heat exchanger at 100 deg so this is probably it's optimum minimum operating temperature. If you have a cooler on it that is causing it to run at 90 then it could very well not be good for it. I cannot find a reference to the upper limits of it's operating range but will keep looking.

Greg 1 · Guru

The ZF 6HP26 transmission has a very good reputation as a strong and robust unit. Most of the issues that I have heard revolve around the magnetron or control module particularly in some BMW models. Each manufacturer has their own module so it can talk to the main engine management unit. The Ford one doesn't seem to have big issues but the BMW one particularly in the X5's do. In some early BF Falcons the heat exchangers were not well put together and failed, dumping coolant into the transmission, which gave them a bit of a poor reputation. Later BF's didn't seem as affected when Ford got on top of it. My BF still has the original exchanger after nearly 14 years, although I am considering changing it as a precautionary measure now after all this time. The Ford copy in the Ranger BT50 possibly is not quite as good as the genuine ZF but still a good unit. Yes some people have problems like most things these days but most don't.

iana · Guru

Greg I read that the thermal bypass valve starts to open at 69' and is probably fully open at 100', as you say this is the designed run temperature. Operating temperatures are a bit sketchy. I believe the limp mode will kick in at 130'.
We are towing a rig that's max weight on the BT50, and have been up some pretty steep range passes. Driving as AUS-KIWI says, the temperature can be managed, but it means slowing down, and I suspect there are a few drivers out there that have trouble with that.
I have taken auto transmission repairers/service persons to task about them wanting to sell me a cooler kit, the war cry is that the heat exchanger will fail contaminating the oil, however when asked to produce a failed heat exchanger, they can't, asked if they have ever seen a failed one the answer is no. The whole story as you have mentioned Greg, comes from the early days of auto transmissions.
One interesting point about the 6R80 transmission, is that you cannot easily fill the transmission with oil unless the vehicle is up on a hoist. This means that if you by chance damage the cooler if fitted at the front of the vehicle, you are stopped, end of story.
The petrol motors of say the falcon, didn't have the complexity of the heat exchangers that the diesel motors have, while the idea of fitting larger inter-coolers to the motor is also being sold, etc., surely charge temperature, engine temperatures also need to be accounted, not just transmission temperature.

Greg 1 · Guru

The heat exchanger on my BF is similar to that used on my Ranger. Certainly not interchangeable but both are quite alike. The 6HP26 in the BF is just like the Ranger in as much as oil filling is very difficult without a hoist. They are also very finicky with regards to correct fluid levels and care is needed to ensure that the level is maintained at the correct amount.

ken thomas · Guru

2 of my friends have just had their trans fail at 100000 due to towing and the ford policy of not needing servicing for 10 years
I had mine first serviced at 67000 and the oil was burnt and just now had it serviced at 100000 and the oil was again slightly burnt and some metal filings in it.
I had the cooler and valve fitted and now bypass the heat exchanger
Cost was $1100
Ken

Aus-Kiwi · Guru

The hotter auto is more to do with fuel
Consumption . If they run cooler esp
When towing ? I doubt you will have issues . The earlier Falcons had BTR auto . Different to ZF .

iana · Guru

Throwing something different in the ring. That is the larger capacity, finned sumps. They offer:-
1/ Oil change with out sump removal.
2/ Magnetic sump plug.
3/ Easier to take an oil sample.
4/ An increase of oil capacity.
5/ Larger surface area for cooling.
6/ No changes required to the existing cooling system, how ever there is a change required for a cable bracket.
7/ No chance of damage and loss of transmission oil from a frontal impact.
8/ No removed heat being past back into the inter cooler or engine radiator.

Driving (towing) today, I notice I only need the temperature to drop 3 degrees, I also notice when stopped, i.e. sump cooling, the temperature drops quite sufficiently.
This sump is ex USA for about $600.
Comments on this please.

outlaw40 · Guru

Iana Wholesale automatics in Victoria do the alloy sump for the bt50 adds about 3 litre of oil and a drain plug .here is the link automatictransmission.com.au/shop/ford-6r80-deep-pml-transmission-pan/

$557.00 including gst . they say there getting reports of 10 to 35 deg temp drop so might be an option for some .

iana · Guru

Thanks Outlaw, I have also emailed a company in the states who have supplied one here fitted to a BT50, asking for more information, particularly modifications required to fit the sump.

outlaw40 · Guru

No worries . as far as i can find out there is no modification required for the one i posted .

iana · Guru

Had an email back from the states, from the company that supply's Wholesale automatics. They have no further information of the BT50 mod. I saw some photos of the BT50, if it is the same one, and a description of the installation. Apparently they had to grind down a bracket that holds a cable, that was months ago, and have been unable to find it since.

outlaw40 · Guru

maybe phone wholesale automatics . straight from the horses mouth so to speak .

iana · Guru

Have sent the Australian supplier an email, we shall see what they have to say. Was hoping for a bit of discussion on here about the possibilities but that hasn't happened, not to worry.

outlaw40 · Guru

Might need to go to the ranger site or somewhere like that to get some feedback as i dont think they are a widely use option in Australia yet. Given the heat sinking ability of the cast alloy and extra oil volume i think they should be a viable alternative and will be going this way myself in the not too distant future . Only drawback with this option is that you still have the potential cooler to engine coolant failier in place so you don't eliminate the possibility of the transmission milkshake.

iana · Guru

Reply back from the supplier, apparently selling heaps of sumps, last import has sold out, as has the next shipment. Of course they suggest I fit a transmission cooler instead of. I would go along with that if only the niggling questions were satisfied. For instance, reading an article explaining inter coolers, it says "An intercooler is necessary in order to extract the maximum performance from a forced induction engine. Without an intercooler, you are almost defeating the purpose of forced induction. etc. etc. This heating effect negates some of the benefits of forced induction, and that's why intercoolers are an important part of any high performance forced induction engine". So why are the transmission heat exchangers expelling their heat in front of the inter cooler?

outlaw40 · Guru

Looks like you have got your answer , just have to wait for stock . will be interested to hear what results you get if you go the larger pan route or if anyone else has gone that way.

jontee · Veteran Member

G`day ,

Before fitting the deeper pan I would check out the effect on ground clearance . There will be a reduction.

Cheers ,

Jontee

iana · Guru

This is what I am leaning toward re fitting an oil cooler to the BT50. It seems the best compromise although not perfect. The fan is rated IP67, and installing the cooler like this seems an accepted method. Would have liked to mount it more in the airflow, but there is no room.

Jaahn · Guru

iana wrote:
This is what I am leaning toward re fitting an oil cooler to the BT50. It seems the best compromise although not perfect. The fan is rated IP67, and installing the cooler like this seems an accepted method. Would have liked to mount it more in the airflow, but there is no room.

Hi Iana smile

Just for comparison to a different cooler type. My Sprinter minibus (early type) and Toyota Coasters and other brands and models too, have the air conditioning condensors mounted under the bus at one side. Just for practical reasons because being a bus, they need a big condensor. These are mounted underneath near the side panel with a grill and have several fans to blow the air through. The fans often do not run much driving but if in traffic and very hot they all cut in fully and you notice the noise as they cut in and out.

So just pointing out it is common practice to put a cooler with a thermo fan under the vehicle. Obviously protect it from road spray and stones and put it in a spot with air flow as much as possible.

cheers Jaahn

-- Edited by Jaahn on Thursday 19th of March 2020 08:51:54 AM