Transmission Overheating - anyone else?

[fuzznuts]

Good idea, Tripod1404. I have not tried either of those things which I will add to the list the next time I am able to test. I have not found a set of inputs that allow me to get torque converter status unfortunately but will keep an eye out for it.

 

[RUN-8]

Unfortunately the most expedient method to solve this is to use 4Lo. There was a member on the Tundra forums who posted a similar (almost identical) problem with the 3rd Gen Tundra 10 speed overheating under nearly identical conditions.

Instead of trying 4Lo or having a dedicated liquid to air cooler installed he may have sold the truck. All attempts from other users to get him to try 4Lo were met with similar resistance as the OP here.

As equipped the OP’s Land Cruiser needs 4Lo for the conditions he is using the truck in. You might not like it, but that is the reality of your situation. Installing an external cooler might solve it completely, or mitigate it, but until then use 4Lo or get rid of the truck.

 

[fuzznuts]

I am not opposed to using 4LO, it simply means the vehicle is not up to task in my personal opinion and ultimately will lead me to sell the vehicle as a result. I can't put the vehicle in 4LO on a paved or gravel mountain road and hold up traffic or drive 15 mph on a 45mph paved road simply to keep the transmission from overheating so it is really only a half solution at best (using it when off-road).

I would love to iknow if others here are going into 4LO at the first sign of a hill. I have simply never had to contemplate this with any other 4WD vehicle I have owned or driven which impacts my ability to accept that as a reasonable solution. If this is really the answer, it would mean a 2-4 day Alpine Loop trip turns into a 3 week crawling adventure, I am being facetious to an extent.

With regards to my comment about low end power/torque for off-road use - it is almost exactly what is described in this thread. The vehicle is working way too hard to move its 5000lbs from a stop vs my 2007 GX470 which I was hoping this would replace but is not coming close to being able to so far.

 

[berry802]

Good idea, Tripod1404. I have not tried either of those things which I will add to the list the next time I am able to test. I have not found a set of inputs that allow me to get torque converter status unfortunately but will keep an eye out for it.

Do you know how much elevation you've climbed when it started to overheat?

 

[LCOceans]

I am sorry if I missed this part, but what grade are you driving up? Any idea on how steep this is and how long of a journey up the hill? Are we talking short distance or miles? This could help in the assessment of the problem?

 

[KyLandcruiser]

I’ve got an 99 lx470. These have a decent sized tranny cooler. I was going down a gravel road and not going very fast. I could see the tranny temp via scan gauge start to rise. I moved the shifter to a lower gear and that solved the problem.

 

[fuzznuts]

6600ft -> 9000ft over 20 miles of paved and gravel roads with speeds anywhere from 10-45mph

 

[RUN-8]

The 10 mph stuff is probably the culprit. Transmission will be running with the torque converter unlocked, just pumping away and building up heat.

 

[fuzznuts]

The 10 mph stuff is probably the culprit. Transmission will be running with the torque converter unlocked, just pumping away and building up heat.

You are likely not wrong but you can’t take the switchbacks much faster nor the turns on gravel roads in this state park either. When I get a chance I will fire up the ole 470 and see what temps it records on that same drive.

If others are able to share what temps they are seeing for normal city driving please let me know.

 

[Tripod1404]

You are likely not wrong but you can’t take the switchbacks much faster nor the turns on gravel roads in this state park either. When I get a chance I will fire up the ole 470 and see what temps it records on that same drive.

If others are able to share what temps they are seeing for normal city driving please let me know.

I don't know about Toyota. But tow/haul mode in some other manufactures locks the torque converter, which reduces slip and overheating, so it is worth a try. Manually using a lower gear may also achieve the same thing.

 

[fuzznuts]

I don't know about Toyota. But tow/haul mode in some other manufactures locks the torque converter, which reduces slip and overheating, so it is worth a try. Manually using a lower gear may also achieve the same thing.

This is fair and something I will absolutely try. I simply had not given it any thought to do this as I never had an issue with my past vehicle, it just worked however If this is what it takes for this vehicle to just work then it is something I can work with. I suspect an actual transmission cooler would go a long way to help the situation however right now I am not terribly keen to throw money at this and do not relish fighting with Toyota if/when my transmission grenades itself and they blame a transmission cooler. They certainly have enough problems between the Tundra's and Tacoma transmission problems.

I am going to continue testing including doing some of the things mentioned here (thank you all) and see what results I get and will be sure to report back. Time will tell if this is a problem with my specific vehicle or not. Worst case is I dump it, take my haircut, and get the 200 series I think I should have gone with from the beginning I do hope this 250 proves me wrong though.

 

[RUN-8]

If your transmission grenades itself and you have an aftermarket cooler on it you could always return it to stock before you see the dealer.

Chances are a good sized transmission cooler will solve this issue quite nicely and improve the longevity of your transmission in the long run by keeping the fluid cooler.

 

[Don]

The 10 mph stuff is probably the culprit. Transmission will be running with the torque converter unlocked, just pumping away and building up heat.

He should be able to drive as described without the transmission overheating. He should be able to tow a 6000lb trailer on the uphill route without a problem, assuming outside temps are not unusually hot.

A photo of the code/warning should be enough for the tech to begin investigating the problem.

 

[RUN-8]

He should be able to drive as described without the transmission overheating. He should be able to tow a 6000lb trailer on the uphill route without a problem, assuming outside temps are not unusually hot.

A photo of the code/warning should be enough for the tech to begin investigating the problem.

Unfortunately towing at low speeds up hill is a recipe for overheating a light duty transmission.

Go watch some testing by TFL Truck YouTube and watch 1/2 ton after 1/2 ton fail their “Toaster” test. Transmissions and engine oil invariably get too high.

For whatever reason manufacturers have abandoned stand alone liquid to air transmission fluid coolers on anything that isn’t a 3/4 ton application or larger.

This is of course a mistake, and will cost the end user money and time to correct with an aftermarket solution.

 

[Don]

The water pump is belt driven, correct? Low range may simple provide higher revs and more flow across the transmission cooler. I would like the center diff on dirt if that surface seems more problematic and select a manual gear that keeps revs up somewhat in high range.

Also, Sport Mode may keep average revs higher

Another thought is that increasing tire grip might reduce torque vectoring, assuming the problem here is the vehicle aggressively managing traction on dirt.

Another Another thought. Turn traction control off as an experiment

 

[fuzznuts]

The water pump is belt driven, correct? Low range may simple provide higher revs and more flow across the transmission cooler. I would like the center diff on dirt if that surface seems more problematic and select a manual gear that keeps revs up somewhat in high range.

Also, Sport Mode may keep average revs higher

Another thought is that increasing tire grip might reduce torque vectoring, assuming the problem here is the vehicle aggressively managing traction on dirt.

Another Another thought. Turn traction control off as an experiment

All reasonable ideas however I keep coming back to the fact the transmission begins to heat up, getting to 3/4 if the way to red ~230F on a winding paved road that heads into a state park road that itself turns to gravel. I do not believe one should have to lower tire pressure, turn off traction control, or even put it in sport mode in order for the transmission to stay cool in those conditions.

I would argue, like Don is saying, one shouldn’t have to do anything different than if they are putzing around the city I order to drive these types of roads.

If the vehicle was maintaining normal temps and only getting hot / overheating when on the tame dirt trail at the end of this drive then accepting the limitations of the vehicle and using 4Lo while Kia and Subarus drive past may be needed. To me, the problem does not start when off-road, it starts on the road where the vehicle begins to overheat where using tools like 4Lo, lower tire pressure, etc are simply not possible or advisable.

 

[Tripod1404]

The water pump is belt driven, correct? Low range may simple provide higher revs and more flow across the transmission cooler. I would like the center diff on dirt if that surface seems more problematic and select a manual gear that keeps revs up somewhat in high range.

Also, Sport Mode may keep average revs higher

Another thought is that increasing tire grip might reduce torque vectoring, assuming the problem here is the vehicle aggressively managing traction on dirt.

Another Another thought. Turn traction control off as an experiment

I believe water pump is cam shaft driven.

 

[KyLandcruiser]

The Kia and Subarus may have a cvt. Those don’t shift through gears.

 

[Tripod1404]

The Kia and Subarus may have a cvt. Those don’t shift through gears.

Regardless of the type of transmission. Going uphill should not cause the transmission to overheat.

 

[KyLandcruiser]

Regardless of the type of transmission. Going uphill should not cause the transmission to overheat.

It will if the transmission is constantly shifting. I got the one in my 99 lx470 pretty warm one time. I was on a gravel road with a speed right between 2 gears. I just moved my shifter down which solved the problem. The lx470 has a decent sized tranny cooler.