Hungry Valley trip and the things I learned (1 Viewer)

[NLXTACY]

WOW! So i'm not the only one and MAYBE this means there isn't necessarily something wrong with the truck. BUT, holy hell this is really scary. CDL off or on doesn't make a difference. What is the Mr. T's reasoning for this one?

This is very disconcerting. So now why aren't more people experiencing this issue? What are they doing differently that do not cause this to occur?

I just went out and tried to stall by rolling backward on a hill and was successful each time I tried.

- CDL Locked
- Low on the transfer case
- Low on the transmission
- Foot off the brake
- Rolling backward slowly

It took a few seconds for it to stall, but I can attest that there was no ABS pedal feedback and the brake was wicked hard to push; it did little to nothing to stop me as I pushed and I was pressing as hard as I could.

There was certainly much less braking power than I had imagined there being; I'm glad I experienced the feeling in a controlled situation. I can picture big trouble if this were to happen on a trail ride with a line of rigs behind me.

 

[Beowulf]

it did little to nothing to stop me as I pushed and I was pressing as hard as I could.

Are you saying you could not stop the vehicle with the brake pedal?

-B-

 

[NLXTACY]

Sure what it seems like. It definitely was in my case.

 

[Chaldaean]

Are you saying you could not stop the vehicle with the brake pedal?

Yeah, Beo, I pretty much coasted to a stop. The brakes may have scrubbed a marginal amount of speed, but I definitely could not stop the truck from rolling backwards by using the brake.

 

[NLXTACY]

So much for doing Lion's Back in my LX

 

[NLXTACY]

Alright folks, image THIS but in reverse!!

 

[NLXTACY]

Also for the record, this confirms to happen now with CDL off AND on.

 

[bluto]

...This is very disconcerting. So now why aren't more people experiencing this issue? What are they doing differently that do not cause this to occur?

In this picture with the 80 on CDL on, 4Lo, transmision L, and rear locker on, I failed to get over the hill twice. Because I was confident the rear locker would get me over the top without gas/momentum - in other words gingerly went up. The surface was very loose and sandy. And I just dug in. The hill I recall may be 4 - 5 80 lengths to get to the top and steep. So there was room for the stall to happen if it was going to happen.

Each time I had to back down, I would always put the gear in Reverse, coast down, and gave it gas as I needed it. Never had the problem Joey and the rest posted.

I have chosen not to do the Pin7 but I did put a CDL switch. I want to add I did make it up the 3rd try with more pedal power and just CDL.

So Im thinking having the trans on Neutral or D (lower forward gears) might be causing this?

 

[NLXTACY]

So Im thinking having the trans on Neutral or D might be causing this?

Well I don't have lockers but that shouldn't matter here. The trans was definitely trans: 4LOW, tranny: LOW

 

[bluto]

Well I don't have lockers but that shouldn't matter here. The trans was definitely trans: 4LOW, tranny: LOW

Yeah I know. But I just wanted to include everything so all bases are covered for reference.

 

[retrofive]

Also for the record, this confirms to happen now with CDL off AND on.

And ABS as well possibly?.

 

[Chaldaean]

And ABS as well possibly?.

In my case, the ABS was off because the CDL was engaged. I can't test it without the CDL at the moment as I took my front drive shaft off to replace the ujoints.

 

[retrofive]

In my case, the ABS was off because the CDL was engaged. I can't test it without the CDL at the moment as I took my front drive shaft off to replace the ujoints.

Man, Im struggling today trying to make any sense to anyone (my fault) LOL.

While watching this thread there has been comments of whether or not ABS played a factor. I realize that with the CDL engaged the ABS should (I dont technically enough to say 100%) turn off.

If the ABS was working like it should CDL on/ABS off, CDL off/ABS on. That should eliminate the ABS theory. Yes/No?

 

[Beowulf]

That should eliminate the ABS theory. Yes/No?

Yes, that should eliminate the ABS theory.

I am still extremely skeptical but trying to remain open minded. The LSPV may be coming in to play here. Coasting backwards down an incline without engine power and vacuum boost would put a lot of the braking pressure on the rear brakes. If, for whatever reason, the LSPV is not working properly then the brake bias would be disproportional to the front and the front would be ineffective due to the weight shift.

-B-

 

[NLXTACY]

Actually the LSPV does sound like it could be a factor given the weight bias going downhill in reverse. Just to clarify on my particular truck, there is no lift at all, LSPV has never been monkeyed with and its still the original.

 

[NLXTACY]

I was just checking the FSM to see if this is something I can check myself. Turns out no. Is there an easy way that people have figured out to check the functionality of their LSPV without needing an LSPV Gauge SST part number: 09709-29018?

 

[Beowulf]

Is there an easy way that people have figured out to check the functionality of their LSPV without needing an LSPV Gauge SST part number: 09709-29018?

Most do it subjectively with the "lock the brakes on a gravel road." I'm not confident in that method and I do not recall seeing a way to adjust it or test it that is DIY. I would take it to a brake shop if I thought they would do it properly.

-B-

 

[Chaldaean]

If, for whatever reason, the LSPV is not working properly then the brake bias would be disproportional to the front and the front would be ineffective due to the weight shift.

I was just checking the FSM to see if this is something I can check myself. Turns out no. Is there an easy way that people have figured out to check the functionality of their LSPV without needing an LSPV Gauge SST part number: 09709-29018?

To test both of these points, I could:

- Do the rollback stall again
- Press the brake as hard as I can
- Look for skid marks from the front wheels

Would that give us the low-down on the LSPV?

I may be able to enlist the help of a buddy to take a video of the front and rear wheels during the stall (with brakes fully applied), but can't promise anything.

 

[MB4wd]

Would the e-brake being employed in the stall have made a difference on the controlled slide? There are no natural hills around here to test it.

Matt

 

[NLXTACY]

Would the e-brake being employed in the stall have made a difference on the controlled slide? There are no natural hills around here to test it.

Matt

e-brake was not employed in either of my attempts. In hind-sight I probably should have thought about using it but I was too busy making sure I didn't roll. I'd also be worried about the e-brake stopping the truck evenly left to right, preventing turning or worse a roll.