Transmission Question

[taco2runner]

Hey all,

Long time lurker and I believe this is my first post. I've been a Toyota guy my whole life, and just recently made the move from a 2012 tacoma to a 15 4runner, and I honestly couldn't be happier. My transmission question actually applies to both vehicles, since they have the same transmission, and I have encountered the same problem with both vehicles.

Pulling into my apartment complex, I drive up a very steep hill, and then down a very steep hill to a gate. Illustration for effect _____^ ]

If I get all the way to the gate, my opener won't work correctly, so I put the vehicle into reverse and back up far enough to activate the gate. This puts my vehicle on a steep uphill slope, in reverse. Now, if I continue to sit on that uphill grade, and shift the vehicle into drive, it will absolutely not find drive. It will grind until I throw it in back into reverse, glide down the hill to flat ground, and then put it into drive. I thought this was a transmission issue with my tacoma, but now I'm starting to think it simply has to do with the design of this particular transmission. Can someone explain what is occurring here? I like to think I'm fairly mechanically inclined, and this isn't an incredibly stupid question...but who knows? Thanks for any insight, and I appreciate all this forum has offered to educate me on my new purchase.

Thanks!

 

[LandCruiser]

That ain't normal.

I back into my steep driveway when I have to unload shit and have never had a problem in that exact same situation.

 

[gm350reratliff]

How steep is the hill? I also back up a steep drive and have backed up a steep hill while offroad (with both 4runners) and I haven't ran into this issue.

The only guess is that the pickup tube in the trans is at the rear of the pan which is unable to pick up fluid on that hill. I'd check the trans fluid ASAP and if all else fails take the dealership service writer/tech for a ride to your hill.

 

[wfo9]

I'm guessing It has something to do with the linkage and the angle of the driveline in that particular situation or some type of binding. I really doubt it is fluid related. Fluid starvation would most likely be a slip, not a grind. There are situations where stuff like this can happen. It's not typical, but I don't think it is necessarily a problem.

Personally, I would not worry about it and would just let it glide in N until it would go smooth into D. Or maybe just activate the opener on time ;-)

 

[gm350reratliff]

The more I think about it, I wonder if it's just the Hill start Assist Control or Downhill Assist Control kicking in? Any lights on the dash flash when this happens?

 

[wfo9]

The more I think about it, I wonder if it's just the Hill start Assist Control or Downhill Assist Control kicking in? Any lights on the dash flash when this happens?

I was wondering the same. I think those things turn off in 4L and that is the only time I've been at crazy angles.

As a test, the OP should try the same scenario in 4L (if it is a 4wd model).

I've seen others have strange stall issues on steep hills....

 

[taco2runner]

You know, some sort of assist could possibly be the sort of stupid thing I wouldn't think about. There is a light that flashes, although it goes off as soon as I step on the brake and bring the vehicle to a stop. This always occurs very quickly, as the noise certainly doesn't sound legitimate, but as a result I haven't been able to distinguish which light is actually going off. Maybe I'll give the 4 low thing a shot, and see what the result is.

Thanks for the input guys, any help is certainly appreciated.

 

[BlackWorksInc]

You know, some sort of assist could possibly be the sort of stupid thing I wouldn't think about. There is a light that flashes, although it goes off as soon as I step on the brake and bring the vehicle to a stop. This always occurs very quickly, as the noise certainly doesn't sound legitimate, but as a result I haven't been able to distinguish which light is actually going off. Maybe I'll give the 4 low thing a shot, and see what the result is.

Thanks for the input guys, any help is certainly appreciated.

Is this the light you see on? Or one that says "TRAC," "VSC," and/or "HAC"

 

[taco2runner]

It very well could be, but like I said I couldn't say for sure. I'm pretty quick on the brake once I hear the grinding and the light. I'll try to pay closer attention next time and see if I can make it out. Would the assist make that kind of noise?

 

[wfo9]

It very well could be, but like I said I couldn't say for sure. I'm pretty quick on the brake once I hear the grinding and the light. I'll try to pay closer attention next time and see if I can make it out. Would the assist make that kind of noise?

Wait, so you don't hear this noise until you take your foot off the brake?

I thought it was when you attempted to shift from reverse to drive with your foot on the brake.

DAC itself makes a horrible noise, but I thought you had to push the button to engage it.

 

[mo_mo]

Hill-start Assist Control

Sounds like the hill-start assist control (HSAC) where the vehicle attempts to keep the vehicle from rolling backwards using the brakes on a hill. Solution is more skinny pedal

Should sound likes brakes creeping / grabbing and be accompanied by rolling downhill slightly.

I think someone on here also mentioned that if you really stomp on the brakes on a hill vs just slightly creep to a stop then the HSAC will work better and not do the engage / disengage thing, but I haven't verified.

 

[taco2runner]

Hm, well thats certainly something to consider. I'll try a combo of stomping on the break/more gas and see how it goes. At the very least ill stay on it long enough to try to identify the light. After all, whats the worst that could happen....new warranty transmission haha

Edit: Also...I wonder if theres an easy solution to disable it. I hate it when the truck tries to think its smarter than me. I'll do the driving, no need for all these fancy assists.

 

[wfo9]

Sounds like the hill-start assist control (HSAC) where the vehicle attempts to keep the vehicle from rolling backwards using the brakes on a hill. Solution is more skinny pedal

Should sound likes brakes creeping / grabbing and be accompanied by rolling downhill slightly.

I think someone on here also mentioned that if you really stomp on the brakes on a hill vs just slightly creep to a stop then the HSAC will work better and not do the engage / disengage thing, but I haven't verified.

Again, that feature does not work in 4l as far as I know, because I have never felt it.