Need help diagnosing 2012/4.0

This is the hose. Sorry, I remembered incorrectly, it's to the right of Throttle body. Believe it's just a vapor return. Anyway, I put a spring clamp on it knowing it's not related to my prob. Appt set w/ dealer tomorrow morn. Will let everyone know the outcome. Thx.

 

Dropping the stock tank isn't overly difficult. Either wait until you're low on fuel or have a few jerry cans aside and siphon out your gas. A floor jack to support the tank when you lower it. I used a 2x4 and a few cargo straps over the top of the tank.

-J

 

Update. The Toyota dealer service dept. diagnosed my problem as being the aftermarket driveshaft. Cost to replace:$1k. Although the one I just had install was not inexpensive, and was made in USA, guess I'll be returning it. Toyota tech said the shaft would definitely cause the loss of power and shifting hesitation, so it makes sense (except for the engine being slightly louder. That doesn't make sense to me). Unfortunately the part is on back order and it could be weeks til I get the repair.

 

I scuffed up my propeller shaft going over some boulders once. I never felt like it lost power. The main symptom was major vibrations at 65mph and up. Might be way cheaper to take your propeller shaft to a local tire shop and have it balanced then reinstall and see if that fixes things. They might also be able to tell you if it is no good.

A clunk with reverse might be your brake pads. This can be louder than normal if you forgot to install the retention clips (thin paper clip looking metal that sit on top of the caliper).

obligatory picture:

 

Following. I can’t understand how that could cause a loss of power unless I suppose it’s binding maybe?

 

I’m having a hard time reconciling a driveshaft problem to your stated symptoms. How could a driveshaft randomly prevent the truck from going faster than 50 mph, then later, run normally, or nearly so? Did they give you any insights as to the mechanism they believe is at play here?

 

I felt the same as you, so I inquired and service rep explained that feedback to trans from driveshaft would limit the output, which could explain the shift issues, but I'm perplexed how the computer/sensor would limit power. Doesn't make sense to me and I'm really concerned about dropping the $ if this ends up not fixing the whole issue. Regardless they showed me where the new shaft had already leaked oil/lube at the prop shaft. At this point I am so frustrated. Two months of dealing w/ all these issues and three shops tossing me guesses (which is why I succumbed to taking it to the dealership) leaves me with few options other than getting rid of it.

 

Thanks for the suggestion. Looks like you scuffed your prop shaft pretty good. At least you had fun doing it (assume), all I do is drive to and from work. The after market shaft I had installed corrected the clunk, which was the center bearing being worn. The Toyota service program (which expired a few years ago (lucky me, not), entailed replacing the entire shaft and center bearing, and if i remember correctly the part of the trans where prop shaft bolts to it. Also, I just had all the brakes redone including rotors, pads and calipers.

 

Latest Update: Took the truck to dealership this morn, as they had called me Saturday to let me know the shaft had arrived. Two hours later the service rep informed me that the tech had ordered the wrong shaft and the correct, two pice shaft was $1850 not including labor. Uh, what?! They were very apologetic and offered a return of my deposit, including the diagnosis fee (which would have been waived had the work been completed). At least I had a chance to discuss the issues w/ the tech and ended up costing me nothing but time. I'll be sourcing another shaft myself and return the bad, aftermarket one. It seems I can't win for tryin.

 

Pre-pandemic my shaft was $1300. I thought you were getting a steal of a deal. I scuffed mine up really good trail hunting in Moab. Good luck!

 

I find it really hard to believe your issues could be caused by the driveshaft.

 

I found a driveshaft shop 45 mins away w/ very good reviews, so I took the original for new Collar bearing, joints and a balance check for $350-$400.

I agree, that it seems unlikely this is the cause of my issues except maybe the shift hesitation. But, the driveshaft needed to be fixed regardless. The shaft will be done tomorrow and hopefully back on the truck by this Friday. I'll deal w/ anything still wrong after that.

 

Latest update...Refurbished factory driveshaft went in easily and eliminated the vibrations. But with that done, I could feel the new tires vibrating more clearly and got an alignment done. That corrected 80% of that vibration except at 30 to 40 mph. Took back to tire installer for a re-balance, which I cannot be sure they did, since it still vibrates at the same speeds. Still having the shift hesitation, so the trans fluid change was not effective either, as just this morning, when I shifted into park felt and heard a distinct clunk. Gonna change the plugs tomorrow to see if that helps with engine noise but I doubt it. At this point, I'm not even posting for recommendations or ideas, I just want rid of this f*&$ing headache of a truck. It will probably be my last Toyota ever.