low range first

[vk2ss55 Senior Member Find all posts View Profile Close vk2ss55]

G'day
Went to Mt Walker recently and noticed that with the D4D auto in low range first going down extremely steep slopes the anchors didn't feel too good . I then discovered that at 800RPM idle the vehicle was actually driving forward against the brakes and selecting neutral seemed a better alternative at times . As the auto's lowest indicated cog is 2nd it was also a bit tricky keeping it in 1st cog down these steep hills .
Any advice from auto drivers as to how to force 1st gear would be appreciated .
Cheers Ross

[leachy_9 Advanced Member Find all posts View Profile Close leachy_9]

Re: low range first

G'day
As the auto's lowest indicated cog is 2nd it was also a bit tricky keeping it in 1st cog down these steep hills .
Any advice from auto drivers as to how to force 1st gear would be appreciated .
Cheers Ross

I don't really understand this. My D4D Auto indicates all gear positons D-4-3-2-L. ( L being first gear). On steep down hills, in low range, I select L and the auto is locked into first gear.
Even in low range first gear, you will need to use the brakes on very steep down hills.
I definately wouldn't be putting the transmission in neutral and relying on just the brakes.

Leachy

[ozwapet2 Advanced Member Find all posts View Profile Close ozwapet2]

Re: low range first

Descents locked in low-low are pretty well controlled in the D4-D auto. I find there is quite a difference in gearing between L-2 and L-L. ( ones a bit too low the others a bit too high for most hills around here ). I heard the manual is very good on descents.
No I definitely would not be putting it in N and relying on brakes for steep descents.
I tried this hill descent assist thingy a couple of times ( came with the option 1 pack ) - makes scary noises but seems effective when combined with L-L.

[D4D Addicted PP Member Find all posts View Profile Close D4D]

Re: low range first

I did some very steep hills the other weekend and found the D4D in LL slow enough without brakes but that might be me.

You need to learn how to drive through the brakes. Method is left foot on the brake, right foot on the loud pedal, get revs to about 1200 (until you feel torque converter lock-up) then ease off brake until vehicle moves, use loud pedal to keep revs constant and keep the brakes where they are. Benefit of this method is your brakes are at about 30% so if it goes pear shaped you're already braking and not jumping on the brakes from 0% thus reducing the possibility of a slide. Yes your brakes get warm but nothing like what they get after a few 100km/h stops on the freeway.

There's also the method of going down with the auto in reverse using the loud pedal as a brake but that method is only good for hire or company cars :lol:

[vk2ss55 Senior Member Find all posts View Profile Close vk2ss55]

Re: low range first

D4D...I like the "rent a racer" hill descent principle !
Your 2 foot method sounds interesting but I wonder about driving against the brakes . You say to wait for the torque conv to loche k up...does it still lock in cogs other than 4th ? I think the manual also says that that in LL the conv doesn't lock ?

Have you had any issues with the box getting hot on long pulls in a low gear on hot days ? So far I've been ok but some of the long steep hills out at Lake Lyell have me worrying that the box hates me ! Do you know of anyone fitting trans coolers ?

Cheers Ross

[leachy_9 Advanced Member Find all posts View Profile Close leachy_9]

Re: low range first

D4D...I like the "rent a racer" hill descent principle !

Have you had any issues with the box getting hot on long pulls in a low gear on hot days ? So far I've been ok but some of the long steep hills out at Lake Lyell have me worrying that the box hates me ! Do you know of anyone fitting trans coolers ?

Cheers Ross

Towing a Tvan through the Vic high country on a 38 Degree day I was monitoring my coolant temperature via a Scangauge (don't relay on the Toyota coolant temp gauge, it is overly dampened and you will over heat before the gauge moves) and once it hit 100 Degrees I would stop and give the Prado a break until the coolant temp. dropped back to 90 degrees. This only happen on the steepest/longest hill climbs.
During this the auto trans temperature warning light never came on (apparently it is set at 107 degrees). But considering the engine cooling system, which also cools the trans fluid, was getting to 100 degrees the transmission must have been close to max temp.
I am planning to have a trans oil cooler fitted to not only protect the transmission but als to take some of the load off the engine cooling system.

Another thing I found out during this is that the A/C shuts down once the coolant temp, reaches 98 degrees.

Leachy

[ozwapet2 Advanced Member Find all posts View Profile Close ozwapet2]

Re: low range first

D4D...I like the "rent a racer" hill descent principle !
Your 2 foot method sounds interesting but I wonder about driving against the brakes . You say to wait for the torque conv to loche k up...does it still lock in cogs other than 4th ? I think the manual also says that that in LL the conv doesn't lock ?

Have you had any issues with the box getting hot on long pulls in a low gear on hot days ? So far I've been ok but some of the long steep hills out at Lake Lyell have me worrying that the box hates me ! Do you know of anyone fitting trans coolers ?

Cheers Ross

The "left foot braking" method is standard technique taught by 4WD training instructors for steep descents in an automatic vehicle.

Putting it in reverse is not mentioned however :wink: ( although I have seen it done )

[Daz Senior Member Find all posts View Profile Close Daz]

Re: low range first

Do you know of anyone fitting trans coolers ?

Try here
http://www.pradopoint.com/viewtopic.php?f=10&t=3776

[charlie Junior Member Find all posts View Profile Close charlie]

Re: low range first

Sorry if I'm stating the obvious but when moving down to first gear the lever will stop at "2" and then you need to push it to the left to force it to engage first gear. If your in LL then be careful to be going slowly as it will make the car slow suddenly. Then going down hill I let the car roll against the engine and gently use brake to prevent it speeding up.
This was the technique shown in my basic 4WD course.
best regards

[Guest Close legweak]

Re: low range first

My VX runs away in low first, but when I put the hill descent control on, it is the s l o w e s t vehicle I have ever driven. In fact, it is so slow friends in disco 3 and 90 series have time to get out, have a chat, and amaze at the nasty ABS noises coming from my car.

They never let me go first......

legweak.

[D4D Addicted PP Member Find all posts View Profile Close D4D]

Re: low range first

My VX runs away in low first, but when I put the hill descent control on, it is the s l o w e s t vehicle I have ever driven. In fact, it is so slow friends in disco 3 and 90 series have time to get out, have a chat, and amaze at the nasty ABS noises coming from my car.

FYI the ABS reservoir is only small, when it has no more pressure the downhill assist control will stop working and the car will lunge forward at whatever gear you're in. Learn to drive without the gadgets as it's much safer.

[vk2ss55 Senior Member Find all posts View Profile Close vk2ss55]

Re: low range first

Charlie
Thanks Mate , I hadn't noticed that you could move the lever to the left for 1st cog .

Cheers
Ross

[Schaffer Addicted PP Member Find all posts View Profile Close Schaffer]

Re: low range first

The "left foot braking" method is standard technique taught by 4WD training instructors for steep descents in an automatic vehicle.

I was taught that and it's called Brake Throttle Modulation or BTM

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: low range first

FYI the ABS reservoir is only small, when it has no more pressure the downhill assist control will stop working and the car will lunge forward at whatever gear you're in.

If this is happening then you have a problem and need to take it to a dealer. The ABS/Master cylinder has a pump in it to supply pressure and Down Hill Assist should work indefinitly....

Mick

[D4D Addicted PP Member Find all posts View Profile Close D4D]

Re: low range first

FYI the ABS reservoir is only small, when it has no more pressure the downhill assist control will stop working and the car will lunge forward at whatever gear you're in.

If this is happening then you have a problem and need to take it to a dealer. The ABS/Master cylinder has a pump in it to supply pressure and Down Hill Assist should work indefinitly....

Good to know as I had been informed differently however I won't be testing it out.