New question on Highlander

[Denny_A]

Originally Posted by rickst29

I hope this post is in time for your model-year-end shopping, *if* the issues I bring up are a factor.

First, note that the electrical motors on the HiHy (as well as the Prius, and all such vehicles) are at the wheels-- and therefore prone to damage by dust. Driving within an RV park should be done VERY slowly, to avoid kicking up a lot of dust--

and if you're gonna drive on dirt ROADS to reach your destinations, or "tour" after you've parked the TM, then the hybrid is gonna be taking a lot of abuse which it wasn't designed to handle. It's a fantastic vehicle, as long as you stay on pavement.
- - - -snip------

Ummmm....are you SURE? Toyota must have made my Prius with a special mod, just for me!

The Motor is snuggled up close to the underside of the bonnet. It is completely enclosed and sealed. A downdrive chain from the motor powers the reduction gearing to the transaxle. The motor ALWAYS turns when the wheels are in motion. The engine ASSISTS the motor or provides power alone. The motor can power the car alone whilst the engine is off as well. The HiHY uses the same HSD system as the Prius. [Caveat: I am not familiar with the rear wheel motor on the HiHY 4WD.]

The motor is NOT at the AXLE. What was your source! My source is both of my Prii .

[rickst29]

http://www.toyota.com/vehicles/2006/...er/models.html

includes the following, in italics, at the bottom:

"Highlander Hybrid in 2WD or 4WD-i is not designed to be driven off road.

Toyota Highlanders are designed to meet most off-road driving requirements...."

And this is where I remembered reading it. But maybe their disapproval isn't related to dust, but rather the risk of short circuits when driving through mud or water?

Looking at a diagram, I see that the MG2 and MG1 motors are NOT on the axle. I was CONFUSING IT with a totally different system. My apologies and thanks to you for setting me straight on "Hybrid Synergy Drive" motor locations.

We have a 2006 Hybrid Highlander and 2006 2720 and have been out twice with this setup. The first was a flat trip of about 300 miles. The Highlander will pull the 2720 on the Interstate at the speed limit with no problems, although I usually was closer to 65 mph (CO speed limit is 75 mph). The second trip was up a gravel road ascending 4,000 ft. (from 7,000 to 11,000 ft) over 20 miles. I ran the a/c to see what would happen. Close to the top, the engine temp light came on, but went off soon after the a/c was switched off. The only issue surfaced on the way down. I'm used to driving Colorado mountain roads and saving brakes by downshifting and taking it easy on the downhills. The hybrid highlander has ONE low range that can be used for downhill. It coasts extremely well when not in this gear - very minimal engine braking. Even in the lower gear, the engine braking was not substantial enough to avoid heating up the brakes on the Hybrid on the way down. We could smell them by the time we were down although there was no indication of fading. The brakes on the trailer were also consistently used on the way down, sometimes by themselves on slow curves. Average speed on the way down was probably 25 mph, so a long descent while towing on a paved road at higher speeds may be a problem. We have not tested this yet. BTW, the hybrid doesn't do much for gas mileage at highway speeds since there is little/no electrical assistance. One would probably note increased mileage while towing stop and go through cities.

[Denny_A]

Originally Posted by PaulinCO

We have a 2006 Hybrid Highlander ......snip.... The only issue surfaced on the way down. I'm used to driving Colorado mountain roads and saving brakes by downshifting and taking it easy on the downhills. The hybrid highlander has ONE low range that can be used for downhill. It coasts extremely well when not in this gear - very minimal engine braking. Even in the lower gear, the engine braking was not substantial enough to avoid heating up the brakes on the Hybrid on the way down. .....snip.....

My Prius has a "B"; position in it's shift selection. The "B" selection is soley for the purpose of using powered engine braking to assist on steep downhills (or if you just want to decel quickly w/o braking). I assume the HiHy has the same mode. Is that what you referred to when you wrote "low range" for downhill? If so, then Toyota must not have had the added momentum of a trailer in mind when the "B" mode was spec'ed!

Denny_A

Yes, that is what I meant. We previously owned a 2002 Highlander V6 and it had 3 ranges. The lowest was lower than the current B range on the hybrid and would have been more suitable for towing. The way Toyota applied the hybrid technology to the Highlander seems to have been to increase power without a corresponding decrease in fuel econonmy rather than a straightforward attempt to just increase fuel economy. Therefore, wrt power, the hybrid should tow better and that is our experience vis a vis the older Highlander (the exception being the braking situation). Perhaps they don't tow a lot of RVs in Japan! :-)