Driving an automatic

[Enigma]

One would think it would be as automatic as it sounds, but at least in a big heavy Land Cruiser it's not.....

I've had this 80 series for about 4 years now, and only twice in that span has the transmission temperature light gone on.
The first instance was last summer, when driving up out of Coalmont towards Lodestone lake. I was just in drive, heading up, no issues with power so why even consider changing gears? But near the top the warning light comes on. I shift into low range, and it goes off.
The second time was just this past weekend, similar circumstance. Heading up the road to Hemlock ski resort, and near the top the light comes on. Down into low it goes, and the light goes off.
Any other vehicle, such as my previous Tacoma, I would never even consider babying the transmission so much, just put it in D and go.
I do have an aftermarket tranny cooler in front of the engine radiator.
So to minimize this occurence in the future, should one be dropping down into 3rd or 2nd? Again, power is not an issue, just the damn tranmission temperatures.
It's times like these I would love a manual tranny again, but that ain't going to be happening.

 

[canucksafari]

I always manually shift the wife's Safari and have taught her to do the same. Going up the steeper sections to Hemlock it is in 2nd and D for the other. I am suprised it was getting hot going up Hemlock in winter temps and also having a tranny cooler. Was it hunting a lot? That is what will get the auto hot. A shift kit with a torque converter lock-up switch will prevent that. At slow speeds, not much air is going through the tranny cooler. You could install an electric fan on it with a thermo switch connected to a sensor in your ATF circuit. For you it should be fairly easy and cheap with a 12V rig.

When was the last time you dropped the ATF and checked the ATF filter?

 

[jcolvin]

One would think it would be as automatic as it sounds, but at least in a big heavy Land Cruiser it's not.....

I've had this 80 series for about 4 years now, and only twice in that span has the transmission temperature light gone on.
The first instance was last summer, when driving up out of Coalmont towards Lodestone lake. I was just in drive, heading up, no issues with power so why even consider changing gears? But near the top the warning light comes on. I shift into low range, and it goes off.
The second time was just this past weekend, similar circumstance. Heading up the road to Hemlock ski resort, and near the top the light comes on. Down into low it goes, and the light goes off.
Any other vehicle, such as my previous Tacoma, I would never even consider babying the transmission so much, just put it in D and go.
I do have an aftermarket tranny cooler in front of the engine radiator.
So to minimize this occurence in the future, should one be dropping down into 3rd or 2nd? Again, power is not an issue, just the damn tranmission temperatures.
It's times like these I would love a manual tranny again, but that ain't going to be happening.

The solution is simple: drop into a gear or speed up so that you can keep the revs up above 3000 rpm when climbing hills if you can not stay TC-locked-up. The 80 series diesels have a particularly inefficient torque converter at low revs. I've got a tranny temp gauge right on the outlet (before the cooler) and 3000 rpm is the "magic number"; below that, the temps will climb up to the danger level of 150 C, above that I've never seen them go over 110-120 C. The tranny cooler helps some but can't keep the inefficient TC cool enough; they cool the oil overall but the TC can cook regardless of what size cooler you have. I've heard that Rodney's Wholesale has a replacement TC that won't cook itself (and will probably boost fuel economy). Once the warning light is on you are probably doing damage to the TC. Sometime I will blast up hills in auto just to keep the TC locked, or to keep the revs over 3000; other times I have to drop down a gear. This recommendation goes double if you are towing.

 

[BCR4619]

*cough* extreme vb *cough* lol prob the most expensive option out there though, too bad you didn't have the ECT as you can do what John suggested and install a switch.

These tranny get freakin hot though, I can practically cook something on my tranny cooler if I'm unlocked going up laurentian crescent to my house, locked on the other hand i can still touch it.

 

[Cruisin']

What Jonathan said. I have been having thoughts of putting an electric fan on the tranny cooler for slow climbs when you just can't get the air flow. I have a gauge on mine right on the outlet, and it blows me away how fast temps climb going up hills where I can't keep the TC locked up.

I put a bottle of Lube Guard in it a while back, and that lowered temps by about 10deg F across the board. Snake oil that actually helped? Cool!

In any event I suggest getting a gauge and watching it! Make sure its in the line though, and not in the pan.

 

[canucksafari]

I put a bottle of Lube Guard in it a while back, and that lowered temps by about 10deg F across the board. Snake oil that actually helped? Cool!

I was impressed with LubeGuard too. It made a big difference in the shifting.

 

[ikeedikeed]

...3000 rpm is the "magic number...

Do the high RPMs keep the tranny cool simply because the fan is turning faster, or is there some other reason within the torque converter itself?

 

[Granite Grinder]

The real trick to keep the tranny cool is to keep it in lockup, as soon as it starts hunting the temps rise quickly. Once the torque convertor is locked, and everything is running 1:1 all is good.

 

[wrongway around]

ok call me stupid but i have to ask if the wholesale v/b basically only diverts the 3 rd gear journal over to the 4 th gear gear journal for lock up ,what does the t/c do ,being that these tranys heat up at under 60 km. can you not just change the pitch in the veins for a lower stall .i guess the real question im asking is if i could only afford one ,im leaning towards t.c because i have mods in my truck that give me lots of power to maintain 60km in lockup in 4th its the under 60km that scares me, so how do you fix the heat under 60?

 

[ElectricDyck]

A tranny temp guage is a fairly simple install, you can unthread the factory temp sensor, get an adapter for the correct thread of your guage and thread it's sensor in, then you just need to get accessory 12 volt and if you want to get fancy find the dash light circuit to wire in the gauges light. From what I've read the factory temp light turns on at 310 degrees and turns off at 210. Fluid doesn't last long over 250 degrees. You'll be amazed at how fast the temps climb when you keep it in drive up hills.

 

[ElectricDyck]

For heat under 60 you just need to shift down and get the rpms up, whether it's the fan moving faster or the fluid moving through the cooler faster, the temps fall quickly.

 

[d0ubledown]

yep, i like to row my gears in town, and usually speed up for inclines, turn OD off and drop down to 2 if needed, esp when pulling the trailer.

around town though, rowing the gears seems to help alot, keeping in L during crawling traffic, od on/off etc. bigger heavier tires and stock gears, i need all the help i can get...and the slightly higher revs and preventing the tranny from hunting helps me net an average of 13.2 mpg's according to my UGII.

 

[Wheelingnoob]

I just put mine in "D" and hit the Right pedal, no issues so far with lots of steep hills and quite a bit of slow snow wheeling. I drain and fill the tranny pan every oil change to keep fresh fluid in the system.

 

[asutherland]

Jeff - I have the same problem you do. On long hill climbs it tends to overheat. I just put it in 4-low now and it keeps the trans temp and egts down.

Edit - of course that won't help when you are on normal roads at normal speeds. I'd also like to put in an elec fan in front or behind my trans cooler, and put a switch on the dash that I can simply flick on when need be.

 

[canucksafari]

I'd go with a thermal switch Search Results for thermal switch - SummitRacing.com. If you want manual selection too, then add a relay controlled switch to your ATF cooler and fan.

 

[ElectricDyck]

helps me net an average of 13.2 mpg's according to my UGII.

Don't feel bad my dodge work van get's 11 mpg, and goes through trannys every 150 000 km, no matter how I drive it, I think a Sprinters in my future.

I just put mine in "D" and hit the Right pedal, no issues so far with lots of steep hills and quite a bit of slow snow wheeling. I drain and fill the tranny pan every oil change to keep fresh fluid in the system.

I drain and fill every 2nd oil change, but I can sure get the temps high up hills in drive under 60km/h.

 

[canucksafari]

I drain and fill every 2nd oil change, but I can sure get the temps high up hills in drive under 60km/h.

Try the LubeGuard. All you should need is a full bottle the first time and 1/3 - 1/2 bottle every time you drop the fluid out of the pan. You'll notice a difference in shifting and temps.