Need help, have a serious question. Grinding noise, loss of MPG

Ok,

So I have had my truck for a year. I have been trying to figure out why I get such terrible gas mileage sometimes and normal/great MPG other times.

I have notice that when I get the "terrible MPG" that it is generally paired with a grinding noise that happens when I go over steep inclines and declines - here is the noise it makes - this is someone elses but my noise is the same. You can feel the vibes in the center under the drive shaft so maybe trans or transfer??

This is someone elses video but I get the exact same noise and issue over bumps and when the ABS detects slip

https://www.youtube.com/watch?v=DNtXKur0dG4


either way, here is my question.

When I come out of 4x4 and drive my MPG will be at like 11/13 on average with the grinding noise when the ABS detects slippage, could the transfer or hubs not be fully disengaged and causing a phantom 4x4 issue to rob MPG's? Also what would cause the Grinding noise? I just test drove a new truck and it would not duplicate the noise at all under similar circumstances.

When I go in and out of 4HI and back to 2WD a few times I can get it do "pop" out of 4x4 and then I notice that steering is lighter and the truck gets 16/19 MPG in the city with "no grinding noise" on incline/slipping.

I have asked the dealer to look into this, brought them on drives they have felt and heard the noise but they will not investigate the noise. Other people have it but not all and its only some of the time with my truck. I wouldnt care if it was just a noise but its sounds like grinding gears or something that vibes the whole truck.


Thanks for your help and I really want to solve this..

 

That ain't right! Go to another dealer or contact Toyota Customer service to start a claim.

 

We are way beyond that. I have taken it to several dealers... I think im on my own for this one. I had a case open.. I dont think they know what the issues is or are wanting to tackle it. I have talked to several other guys who have the grinding noise and low MPG so it seems to be a thing because a lot of other guys get great MPG or better thank what its supposed to get

 

Dang! If you are out of pocket then I'd suggest finding a 4x4 shop and have them dig in to the drive train.

 

Something definitely sounds, well, wrong. I agree with the above, taking to a 4x4 shop to have it checked out, or an independent shop you trust.
Are you under warranty? I'd save receipts and document dates/times with Toyota if you haven't.

Sucks man. Good luck with it.

 

Have you exhausted all the local dealers? If so yeah go to a good shop and try to recoup your cash later from toyota... sorry to hear

 

Is the suspension stock or modified?

 

Send a email to Jim lentz the Ceo
Jim_Lentz@toyota.com

 

How in the hell are you "on your own" on a year old truck that is still under warranty? Guess that I'm just not understanding that as a concept, unless they told you it is something you did to the truck.

Edit...nevermind, I see you have modded the driveline.

 

This noise has been since my 5th day in the truck, before any mods. Suspension has done nothing to it except make the truck more awesome'er...

Im on my own because I have taken it to several dealers and they claim thats a "normal" characteristic of the truck... haha like wtf??? its supposed to grind like that? NO... The fact that I modded it is irrelevant due to the fact that the issues occurred before mods. Corp got involved. I emailed the ceo already. They gave me 125k mile warranty. But, they wont investigate the noise or issue. They say nothings wrong and give the truck back but, I show them the noise. show them my avg mpg and still no love from the dealer.

The dealer doesnt want to investigate they only want to fix a specific problem. They dont get paid by toyota unless they know the issues and fix that issue. If they are hunting for a problem they might have to pay a tech an hour or two labor and toyota wont give them money for that essp if they cant find the cause of the issue.

Im hoping to find someone on here who has intricate knowledge of the Tcase and 4x4 system that might be able to shed some light one why... this occurs and causes the 1- noise, 2- reduction in mpg, 3- if there is something wrong with 4x4,t-case,actuator or something random that I may not have thought about and should explore

 

It sounds to me like your tires are rubbing. You got a photo of your truck?

I gotta ask, why didn't you take it to the dealer before you changed the stock configuration?

Certainly taking it in after you've modified the suspension and increased tire size would add complexity to the diagnosis.

SB

 

Not trying to be a jerk but did you read the post? I have taken it in to more than 3 dealerships and I took it in 5 days after I bought it. Before any mods. I am 100% sure it's not the tires. It did it bone stock and after mods. I have also done a body mount chop so there is no rub.

It's not a tire rub. It's grinding gears. You fee it in the drive shaft. Even when the tires are straight.

 

Are you reversing once you go from 4hi back to 2wd?

 

Could it be the engine/transmission mounts going bad?

 

Sorry about that, I missed that.

SB

 

I would research and find a legitimate transmission/drivetrain shop in your area(I'd even drive if there's a shop worthy of it) and have them troubleshoot it. If your mpg are down it's obviously because something is binding and causing unnecessary drag in the driveline.

 

Could it be your leaf springs/bushings? The loss in MPG coincidence?

 

Yes. I have. 4lo -4hi - 2wd in reverse. Often that will get you completely out of 4x4 but there are times when it says it's out and I'm getting 11mpg and times where it really is out and I'm getting 16pmg.

 

Correct, The noise only happens over large bump/sharp incline/declines and when the slip indicator lights up on the tach. The loss of mpg is constant until you get it out of 4x4.

I think that it's not properly engaging the Atkinson cycle, or the hub is rubbing, or the tcase isn't properly/fully disengaged. I've got under and spun the shaft when it says it's in 2wd and it spins freely so that's good. But I am looking for things I may have missed or something that 2nd gen owners have dealt with or someone might be able to think outside the box for some ideas

 

That's what I'm thinking. I'm just wondering what it could be. Maybe an area to start the search or the "likely culprit" as the cost can add up quick if I have to pay out of pocket. I'm also worried about warranty if someone other than the dealer is messing with the drivetrain.