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Discussion Starter #1
extreme towing question

I posted this in the Sequoia section and they suggested I post it here also as many of you tow a lot too so here goes.


I live on top of a very steep hill that has a 250 foot long driveway and I have noticed when I pull my approx. 3300lb trailer up the hill it STINKS. It smells like something is really burning like transmission fluid or something. I always put the gear in L but I leave the center differential in either 2wd HI or 4wd HI. It doesn't matter either way it seems to be a real strain and stinks.

Most of the towing on the highway is fine so what should I do? Am I damaging something? Should I put the vehicle in 4wd LOW and leave the center differential unlocked? Or does that automatically lock it preventing me from steering on a concrete driveway? It is a curvy drive too so I need to turn.

It is a 2003 and so far I have not found anyone that will offer any synthetic tranny fluid for it. I have checked Mobil, Amsoil and Redline and none of the offer anything for the 03. Redline specifically said Toyota changed the fluid in 03 to a proprietary fluid and they don't have a replacement.

I was wondering if a bigger tranny fluid cooler or a fan would help any?

HELP

Don
 

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I am not sure exactly where the smell would be coming from. My first thought would be that your catalitic converters are getting overly hot from the steep hill and they often times smell a little foul when overloaded. I really can't think of any other reason you would be getting a bad smell. I do question why you would put your vehicle into 4wd on concrete? That is certainly not good for the diffs. Sorry probably not too much help for ya..

Jason
 

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Do you have the cooler in the small additional radiator in front of your radiator, or is it only inside the big radiator?

If you don't have the small radiator, you would be well advised to add an additional transmission cooler. It will mount in front of your radiator. If you can do the work yourself, you can get the cooler for about $50, and you'll need some top quality 3/8" hydraulic hose (without end fittings) and some hose clamps. Don't use fuel hose...it might not be able to take the heat. As slow as you're going you might need an additional electric fan in front of this cooler, but start with just he cooler.

Lubegard claims that their black bottle ATF supplement will convert Dexron III ATF (including synthetics) to meet Toyota's ATF characteristics. I haven't tried it. You might telephone them (800-333-lube) and let us all know what they say.
http://www.lubegard.com/automotive/trans_atf_hfm.html

Can you run 4-Lo without locking the center diff on your Sequoia? That would be good for this hill. It makes no difference that you put the shifter in L...your transmission will be in 1st on this hill at slow speed anyway. Well, it makes a big difference going down...L keeps your brakes from overheating.

And, as Jason said, the smell might be something else entirely.


Ken
 

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Discussion Starter #4
YEs my vehicle does have a small tranny cooler on it now mounted in front of the radiator. I was thinking of adding a fan or a larger cooler. It looks pretty simple to do so.

The smell is not the rotten smell of the converter for sure. I know that odor and this is something that is hot or burning.

I am going to check on the 4wd low with out the differentials being locked because that would give me more torque for sure and not overheat the engine as much

Thanks for the fluid tip I will call them today

Don
 

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Whatever you do, do not call 1-888-333-LUBE else you will be tempted to pull out your credit card and talk to the woman of your dreams ! Ha Ha

Don
 

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Don't tundras have a transmission temp warning indicator (A/T)? I would hope if your transmission is getting to the point of something burning, this indicator would go off for you.

Definitely check into lubegard black bottle. Synthetic (amsoil universal ATF or mobil 1 ATF) will run cooler than dino.

Differentials don't hold many quarts of lube, now would be a good time to switch them over to synthetic as well. Try redline (www.redlineoil.com), as they are considered the finest in gear lubes.
 

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Discussion Starter #8
I called Lubeguard and they said the 03 toyota already uses a full synthetic tranny fluid and that his product will allow the use of Dexron type fluid but that it is not "toyota approved" So that means if you had warranty problems they may cause a problem over its use. The 03 requires the use of their own fluid only and offers no specs or anything to use other than Toyota. Unlike the differentials that state the spec GL5 etc


Don
 

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"Don't tundras have a transmission temp warning indicator (A/T)? I would hope if your transmission is getting to the point of something burning, this indicator would go off for you."

I think that is only on the 4WD models..
 

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rotts4u said:
I called Lubeguard and they said the 03 toyota already uses a full synthetic tranny fluid and that his product will allow the use of Dexron type fluid but that it is not "toyota approved" So that means if you had warranty problems they may cause a problem over its use. The 03 requires the use of their own fluid only and offers no specs or anything to use other than Toyota. Unlike the differentials that state the spec GL5 etc


Don
It must be Toyota Type-T ATF. There's no Dexron/Mercon equivalent for it.
 

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Discussion Starter #11
I had the trailer out today and when I came home I used the low range and it makes a huge difference. No stink at all and you can tell it pulls the hill a lot easier.

I think I just found my answer for the driveway.

I may still buy a 6 dc fan for the tranny cooler. Another 10-20 degrees cooler cant hurt anything right?

Don
 

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extreme towing question

ATs have what is called a Torque Converter. It is a fluid coupling between the engine and the transmission. It acts as a Continuously Variable Transmission. At some point, depending on the fluid viscosity, overall gear ratio, engine speed, and vehicle weight, it "locks up", meaning that it functions as a mechanical coupling, i.e., no slippage.

By changing the OA gear ratio, as you did when you decided to try LO range instead of HI, you changed the lock up RPM of the TC. By allowing it to lock up earlier, the trans fluid stayed cooler because the slippage between the stator and the rotor of the TC was reduced.

By towing the trailer up the driveway in HI range, the TC slipped a lot. This generated enormous amounts of heat; that boiled the tranny fluid, and caused the oder that you smelled.

Change the tranny fluid and filter to whatever TMC recommends, and use LO range from now on.

Regards,

Tom
 

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Towing up a steep hill with a Sequoia

This is all my opinion, but here it goes. I have both a 2002 SR5 Tundra and Sequoia 4WD. My Tundra has a locking transfer case, thus it is not recommended on hard sticky services. The Sequoia has center differential which only locks up when you are in 4WL with the Transmission lever in Low. When the orange light comes on and stays solid, the center diff. is locked.

I have a camper that weighs about 4800 lbs. the way I tow it. Anytime I do something like going up a very steep hill, I pit it in 4WL with the transmission shifter in Normal and OD off. This yields less slippage in the torque converter. I also do the same thing when backing the camper up.

On my Tundra I hesitate to do the same thing, unless it is in a straight line, or the wheels are not matched. If you turn with my tundra and the vehicle in 4WD, the drivetrain will bind causing serious stress.

Also, when I tow, I almost always have the OD off. Otherwise, you can get a considerable amount of heat build up in a very short time.

As for the fluids, I can't help you. I have changed everything over to either Amsoil or Mobil 1.

Hope this helps.

Doug
 

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Re: extreme towing question

tohara17 said:
ATs have what is called a Torque Converter. It is a fluid coupling between the engine and the transmission. It acts as a Continuously Variable Transmission. At some point, depending on the fluid viscosity, overall gear ratio, engine speed, and vehicle weight, it "locks up", meaning that it functions as a mechanical coupling, i.e., no slippage.
.....

Tom

The torque converter locks up by a mechanical mechanism when it receives an electric activation signal to do so.


Ken
 

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Torque Converter

Yes that is true about the Torque Converter Locking up from an electrical signal. This usually occurs at a relatively high rpm and less throttle. The way you can tell if it is locked up, is by pressing on the gas pedal some. If it is locked up you will notice no immediate jump in RPM relative to the MPH guage. If it isn't locked up, the RPM will jump a couple hundred RPM immediately.

On alot of vehicles, when the vehicle is taken out of OD, the engineers will have designed the transmission to lock up in more conditions. They now there will be more loads on it, and more potential for damage. An easy way to check this is to go up a hill big enough to require the transmission to down shift into third gear. Keeping constant pressure on the gas pedal, take the vehicle out of OD. If the torque converter locks up, you can usually tell. The RPM will drop, and small changes in the gas pedal will yield no immediate changes in RPM.

Just my observations from an rookie with no formal training, so take it for what its worth.

By the way, there is a great website that explains how a torque converter works and many other things. It is one of my favorite web sites. Check it out - wWW.HOWSTUFFWORKS.COM

Thanks,
Doug

tbdw towing faq
 

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Extreme towing conditions

Doug & Ken,

Good points all. I neglected to mention the mechanical locking mechanism in modern TCs. Originally, TCs locked through hydraulic means only, and there was a small amount of slippage, even at the "stall" (lock up) RPM.

I also did not consider the locking center differential. The oiriginal post did not mention whether there were any turns in the driveway, and I didn't think about how that would affect the drivetrain.

The observations regarding the OD operation are a surprise to me. Since OD makes the O/A gear ratio taller (lower numerically), that would induce more slippage in the TC. I would expect the TC to lock mechanically when in OD.

Regards,

Tom
 

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Re: extreme towing question

rotts4u, glad to hear that you may have found your solution.

pardon my lack of knowledge in this, but center differential? is this something that is controllable in the 4wd model?

i have a 2wd and the only options i have are on the shifter (P N R D 1 2)
 

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Towing with the Tundra

I recently towed my 69 FJ-40 on a trailer to Moab and back and the Tundra did just fine. Trailer weight was about 6500lbs with single axle brakes. The Tundra was loaded at max CGVW (don't think I would admit that it was actually over would you?). I ran OD most of the way through Nevada & Utah. Mileage varied from just under 7mpg fighting a big head wind at 75mph to almost 11mpg pulling the pass from Placerville to Carson City. Found out that it likes slower speeds for mpg. At 45 pulling grades it got almost 11mpg. At 65 and Cruising it got high 9's. Bump to 75 and watch it drop! Then agin, my FJ-40 is 7' tall before it goes on the trailer. Kind of like a Tundra pulling a tall Brick on a Trailer.
 
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