Dealing with step inline without smoking transmission or brakes on an SUV

[naimc]

On a recent trip to Vermont we drove our 2019 Highlander LE V6 AWD up the Burke Mtl toll road, the vehical was loaded with a hitch rack and 4 mountain bikes.

Profile looks like this : https://www.brentacol.com/h/burke_toll
Burke Toll Road is located in Vermont. It is 3737.6 meters long with an average gradient of 14.3% and a maximum gradient of 24%.

I going up I just left the car in D-drive , and let the transmission do it's thing. Once we reached the summit, a "different" smell was coming from the front I assume this was trans fluid ? as if I recall it's vented with the outside air. Engine temps were normal nothing unusual on the dash.

On the way down, manually put the automatic trans in lower gears , S2-S3, while of course just braking with gentle pluses. I also experimented with the Downhill assist mode. ( not really knowing how it works, I read later is using the brakes with ABS)

In spite of all these efforts when we got the bottom of the toll road, the incline continued with a STOP sign , and as other vehicle were on the main road I had to fully stop and oh boy the smoke came off the front brakes with that smell. I could just visualize the pad's "Sizzling" (Raybestos Element 3). I through wow I really am an amateur when I drove manual cars that never happened to me one in lots of driving.

So what could I have done better :
- Final stop : I could have engaged the parking brake, that would have kept the pads off the calipers , that final stretch of read was not that step, I just had allot of speed.
- Using DAH , was is really worth it, it probably contributed to the overheating rotors ?
- Keeping the automatic transmission in lower gear such a good idea, these Toyota 8 speeds are dying on the Toyota nation forums they seem very Fragale so sacrificing the brakes does not seem like a bad idea ?
- Don't drive up and down step mountain road's with a Highlander that has undersized brakes ? ( But the view was incredible last week)


Highlander currently has 92000 KM, and the Toyota WS trans fluid was previously changed at 44 000 KM, it will be changed again soon.

 

[KrisZ]

There is nothing really you can do going up the hill. Maybe set the tranny to the lower gear to prevent it from gear hunting, that’s about it.

Going down however, I’m pretty sure the down hill “assist” is what smoked your brakes.

 

[Bailes1992]

Hill descent control is more for off roading to stop the car running away with itself. I think the HDC in my Duster can't be activated above 20mph.

In an Auto, just do as you would in a manual. Drop gears to bring the revs up to engine brake and avoid using the brakes until you absolutely have to.

 

[Highlander 1459]

I've found on really steep downgrades the best gear to select was the gear that required me to use the accelerator pedal to descend the grade....

 

[road_rascal]

Somewhat off topic but I'm not impressed with the Element 3 rotors. I had to have them turned once after 20,000 miles and now I'm looking to replace them (12,000 since they were machined) at about 32,000 miles since I installed them. Last set of Autozone rotors went almost 100k before I replaced them due to rust.

 

[02SE]

I drive up and down steep roads every day just leaving the house or going home. The automatic transmissions will usually stay in the highest gear they can, with less mechanical advantage, going uphill and downhill. I monitor the various temperature sensors, and can usually see a noticeable decrease in transmission fluid temp when climbing steep roads, if I manually select a lower gear than the transmission would while going uphill. Downhill I select a gear that will noticeably keep the speed controlled, without using the brakes constantly.

 

[21_6.7f450]

Run it in tow /haul or Sport mode and gear down. Let the engine slow you down. Watch trans temps.

 

[eljefino]

I've done the Mt Washington Auto Rd which is a similar premise. Automatics, use first gear, and pulse the brakes so air can get in to cool them. Engine revs were 3500-4500 with taps of the brakes if it went above that. I also stopped at a turnoff halfway down and gave my rims the old back-knuckle temp test to see how hot things were getting.

Your mistake was using 2nd or 3rd gear instead of 1st. Transmissions wear out by shifting, IMO, so if you picked a gear and just stuck with it you're doing fine.

MTW levels out a bit near the bottom, so i could go 25 vs the 10-15 I do near the summit. That let the car get more into engine braking vs friction brakes.

You're worried about "sacrificing" brakes when you should be worried about boiling the fluid and losing them completely. That is the hazard of using them exclusively on steep downhills.

 

[andrew_j]

I did Mt Washington auto road in 2015 Pilot with 8 guys in it.

On descent I left in drive 5 speed auto. They want you to pull off and cool brakes which I never did. They were making scraping noises at end however it subsided. I put another 30k on those brakes.

It seemed like the vehicle was using engine as it descended on its own.

 

[21_6.7f450]

Anyone that doesn't know how to control their speed without overheating their brakes doesn't need to drive.
Me in my BIG HONK'EN BRODOZER compensating foe something pickup ,I just turn on tow/haul in the F450 and engage the Exhaust Brake. I have to get on the throttle coming down grades, it will almost stop on its own.
On the F350, I load the tow file, choose a gear at the top for 2500rpms on the way down for my desired speed and let off the throttle. Its MAGIC I tell you.
The Tacoma, I choose a gear for a 3500rpm decent. I never touch the brakes, they remain cool.
Disclosure: The F350 and Tacoma are 6spd manuals so it's easy. The F450, I have to "think" what buttons to push. Haha

 

[naimc]

Update : I changed the transmission fluid dumped the Toyota WS and when with idemitsu : ATF Type TLS-LV. As for the brakes I looked at the this week and found that.


the pad on the right is the inner pad :

These are Raybestos Element 3 pads, I conclude that when I had to come at the stop at the bottom of the hill the rotors were red hot and due the traffic on the main road, I had hold the stop, thus the pads cooked and pad material fused to the rotor , hence the missing chunks of pad material.
Also on a side view, the pad material from the left pad is starting to "seperate" from the metal plate.

The rotor seems ok , I cleaned it up. I would have expected major pulsation, but the braking has remained good with no pulsation. I clean-up the rotor with light sanding, but I think it has a slight bluish hue to it. ( this is Geo coated Raybestos Element 3 rotor)

 

[edyvw]

Update : I changed the transmission fluid dumped the Toyota WS and when with idemitsu : ATF Type TLS-LV. As for the brakes I looked at the this week and found that.


the pad on the right is the inner pad :

These are Raybestos Element 3 pads, I conclude that when I had to come at the stop at the bottom of the hill the rotors were red hot and due the traffic on the main road, I had hold the stop, thus the pads cooked and pad material fused to the rotor , hence the missing chunks of pad material.
Also on a side view, the pad material from the left pad is starting to "seperate" from the metal plate.

View attachment 242278

The rotor seems ok , I cleaned it up. I would have expected major pulsation, but the braking has remained good with no pulsation. I clean-up the rotor with light sanding, but I think it has a slight bluish hue to it. ( this is Geo coated Raybestos Element 3 rotor)

View attachment 242279

Toyota has junky brakes. I mean there is no any way around that. Here in CO, one is always going up or down if spending time in the mountains (obviously). I do drive fast and aggressively, and when I had Sienna (same rotors and pads as on the 2011-2020 Highlander), I would overwhelm them super fast regardless that I downshift like I am driving a manual. Simply, there is not enough rotor surface for weight.
Raybestos is JUNK! Just don't bother. I tried it, took it off after 3-4000 miles. Go with EBC. Get EBC Premium rotors and Green Stuff pads. It worked on my SIenna. Another pad I used was Pagid, but not ceramic, but semi-metallic, Euro compound (available on RockAuto).

Also, going uphill, keep in manual mode and in the sweet spot when it comes to rpms, where you have good torque. That will prevent transmission from constantly hunting for gears.

 

[IndyIan]

I think that was a leave it 1st hill both up and down. Nice high rpms so the torque converter doesn't think about unlocking and the trans doesn't have any options to shift around constantly and mess things up...
The engine spinning at 3-4k rpm making only 40-50hp will do that for 10-15 minutes happily, and the trans shouldn't be making much heat at all. The pads took a bit of a beating to spall like that, but should be fine for normal driving IMO. The brake system is designed to get hot regularly, not quite that much, but once shouldn't be an issue.

 

[supton]

That rotor looks off to me. Maybe it's lighting. Looks like it has sat, got rust, got scraped clean, sat more... just seems dark in color, lacking machining marks. If it's blued like that, I'd replace it (and I'm one to run records for rotors). Pads and rotors are usually pretty cheap.

And just force a lower gear while going up/down mountains. Toyota seems to prefer to unlock the convertor and broil the fluid, as opposed to forcing a downshift and locking the convertor up. No idea why.

 

[edyvw]

I think that was a leave it 1st hill both up and down. Nice high rpms so the torque converter doesn't think about unlocking and the trans doesn't have any options to shift around constantly and mess things up...
The engine spinning at 3-4k rpm making only 40-50hp will do that for 10-15 minutes happily, and the trans shouldn't be making much heat at all. The pads took a bit of a beating to spall like that, but should be fine for normal driving IMO. The brake system is designed to get hot regularly, not quite that much, but once shouldn't be an issue.

It is an issue on OE Toyota brakes and average aftermarket stuff.
The rotors don't have enough carbon. They are undersized, and there is not much heat dissipation. You won't believe how fast you can go from a brand-new rotor to a vibrating rotor. On new VW's is same thing. They cheapened OE stuff (regardless that it is made by Brembo, and size is actually good). I had that same issue on VW Atlas. However, Euro cars are easy as aftermarket support is really good. Problem was solved with ATE rotors. On Toyota, it is bit of "gymnastics" to find good aftermarket stuff.

 

[ammolab]

Going up hill why would the transmission heat up? Lock up torque converters don’t create heat, so just putting extra load thru a gear set shouldn’t crest much more heat. I would shift into a gear that prevents “hunting” shifts on the way up.

 

[IndyIan]

That rotor looks off to me. Maybe it's lighting. Looks like it has sat, got rust, got scraped clean, sat more... just seems dark in color, lacking machining marks. If it's blued like that, I'd replace it (and I'm one to run records for rotors). Pads and rotors are usually pretty cheap.

And just force a lower gear while going up/down mountains. Toyota seems to prefer to unlock the convertor and broil the fluid, as opposed to forcing a downshift and locking the convertor up. No idea why.

Revving it up near 4k makes it probably makes it effectively locked? When did locking TC's become standard? My 1981 Omega v6 3spd didn't have one but at 55mph it was near 2500rpm I believe? No tach of course. The TC seemed pretty tight really.
3spd Neon had about the same gearing and did lock the TC, but at 60mph it didn't change the rpms too much either even at 1/2 throttle.

 

[supton]

Revving it up near 4k makes it probably makes it effectively locked? When did locking TC's become standard? My 1981 Omega v6 3spd didn't have one but at 55mph it was near 2500rpm I believe? No tach of course. The TC seemed pretty tight really.
3spd Neon had about the same gearing and did lock the TC, but at 60mph it didn't change the rpms too much either even at 1/2 throttle.

Yeah, by then slippage should be low. Depends on stall speed and torque through the TC, but unless if it is a loose convertor, 4k is likely low loss.

 

[JimPghPA]

Some mountain decent have areas to pull over to stop for long cool-down of brakes. If so, take advantage of that.

When engine braking besides getting it into the lowest gear with highest possible engine RPMs, load up the engine as much as possible. AC on Max with the fan on Max even in the winter, all lights on external and internal. Heated seats on Max, headlights on high if you can. It really does make a differance, that in some vehicles help the speed stay very low.

 

[meep]

Pretty wild.

First, I wouldn’t beat myself up for finding them smoking at the bottom without being aware. Back in the day, the pedal would start to fade first, and that was the warning that it was time to take action *now*. With the newer vehicles, it seems that smoke comes before pedal fade. I’ve not had a faded pedal since 1996, but I’ve absolutely encountered smoking brakes and used the visuals to help me learn the limit for that vehicle.

That rotor looks off to me. Maybe it's lighting. Looks like it has sat, got rust, got scraped clean, sat more... just seems dark in color, lacking machining marks. If it's blued like that, I'd replace it (and I'm one to run records for rotors). Pads and rotors are usually pretty cheap.

And just force a lower gear while going up/down mountains. Toyota seems to prefer to unlock the convertor and broil the fluid, as opposed to forcing a downshift and locking the convertor up. No idea why.

That dark blue/black is … I’ve never seen anything like it. And you had to put some miles on it with brake engagement before pulling it - why isn’t it shiny silver!? I’m not an expert, but I’ll posit that it has changed temper, and should be replaced.

The Element3 pads took some heat, didn’t they? OP says he returned to service but there was visual evidence of beginning material separation from the back plate. Me, I’d replace them, though frankly most folks would probably just keep using all of it.

Note, newer E3 pads are being noted as lesser quality. I’ll suggest akebono ASP (not ACT) as a good pad comparable with the E3. The E3 has minorly better pad feel, but the ASP is by my limited experience an excellent pad. (ACT is a lower friction pad, most likely very close to oem).

Bleed the fluid…