How to use downshifting when towing downhill with steep grades?

Hey guys,

I'm towing a U-Haul 6x12 trailer with at most a 1,500 pound load. I was in the rockies on i-70 West today and after the Eisenhower tunnel, there was a steep grade (%7) for 7 miles where I was basically riding the brakes the entire way down. I could smell the brakes. I have another downhill trek tomorrow to finish off the rest of i-70 and I want to avoid cooking my brakes like I did today.

At what gear should I be in to take advantage of engine braking? What are the safe speeds for each gear? I'm not afraid of riding in the truck lane and want to be as safe as possible as today was a nightmare.

Thanks.

 

You’ll have to select which lower gear that provides just enough braking to maintain downhill speed without use of your brakes. That speed may end up being lower than you desire but that is a compromise you’ll have to live with for the few minutes it takes to survive towing with a TJ.

 

I would stay in S4, and drop to S3 while going downhill, and uphill if needed. The transmission won't allow you to over-rev the engine.

I drive in S4 a lot, as it keeps the transmission from downshifting so much. I'm well over 3K RPM's at 80. Gas mileage sucks, but the engine can take it.

 

Forgot to mention, 65 is recommended top speed for towing. S3 is probably fine at 65 for braking purposes.

There's a section in the manual on towing that might have more information as well.

 

Did we enter an alternate dimension where the 4Runner is referred to as a TJ?

 

Yep S4 or 5 maybe 3 to uphill/downhill on I 70 if there is a headwind. I 70 sure is a pain in the ass in Colorado. Had the pleasure of dropping a jeep heading up Vail pass westbound. I know

Take my word for it boys.... I had one hand on the wheel and one the shifter... didn't want to startle the Mrs. into a pic with a little street racing.

 

Opps. I spend more time on the other side.
Still, the advice applies. You may need to slow down even more you’d like to use a lower gear that will actually hold you back.
I’d much rather tow with my T4R vs my TJ. Neither one compares to a full-size truck.

 

Wish I could help I only tow on flat land in MI. I can only imagine those hills and towing. Let us know how it goes

 

Well said @runnerjimmy. Was out in May of this year pulling a camper trailer weighing in at 2 ton. She did just fine doing what you described and still had a little left over to drop a jeep pulling a tear drop towards the top of Vail. Trust me folks.... I was in the right lane he thought he be a smart ass and pass me....

 

I assume since the Jeep was going to pass you you had to speed up to “drop” him. Did you feel good about about yourself driving slow and in the way? Was it even better when you inflicted yourself on someone trying to get around?

 

My truck is very heavy, I'm always using the gears to slow it down on steep grades to preserve the brakes. Definitely use the gearbox to slow your speed on those big long hills. I frequently travel Hoosier and that descent into Breckenridge hits 8%+ in some spots. Use your gears!!

 

I daily pop it into S and use 3rd on a long downhill. I "rev match (blip the throttle as soon as I select the lower gear)" some otherwise the shift it a bit harsh.

 

It felt wonderful. And I wasn't in the way. Thanks for your concern.

 

Shift from 2nd to 1st in 4low without braking, that'll wake you up.

 

I must be slow because I can't follow what you guys are going back and forth about. If I were to guess based on John's reaction though, you were in the right lane and when a Jeep was tried to pass, you sped up so he couldn't?

 

The body will come off and the frame will stop like in cartoons.

 

Exactly. I let him pass then he's in front me - he's showed his intelligence trying to pass uphill... I would't want to see his downhill moves. Nuff said. Posted to get a laugh, struck some nerves. No blood no foul and we both didn't bust the 70 mph speed limit.

OP didn't mean to hijack your thread.

 

You're almost better off letting stupid people pass. I trust them more in front of me where I can see what they're doing.

 

Hmm. You're not from Minnesota by chance?

I just don't understand why one should be concerned that somebody else is passing them. Let them go and never see them again.

 

I agree. If someone wants to drive faster, let them have at it.

 

Yup, keep your friends close, your enemies closer, and idiot drivers in front of you lol