Rotational grinding when letting off gas after 35mph

I just had a 6 inch pro comp lift installed on my 21 limited. Since then I have a rotational grinding noise( when letting off gas) that is felt through steering wheel and gas pedal. It only occurs when going past 35mph. Worse when speed increases and i let off to coast. It only does it for a second but noise is constant when in neutral going hwy speeds. Everything is tight and nothing It hitting anything. I checked all fluids and greased u joints. My mechanic and I can not find the issue. Only at 8k miles and the grind does not change when turning. It's also AWD.

 

Prolly cuz you added 3” too much lift.

 

What are your cv angles?

Your front diff angle?

3” is already pushing it without a mild diff drop.

 

CV Angles look good. Diff is dropped to factory location. The lift kit came with new crossmember and brackets.

 

Needle bearing could also do it. But if your angles are good, I can’t imagine it’s that.

Anyone know if Limiteds are more sensitive to NB issues with lifts?

 

I can imagine it, lol. Actually not much imagination required, since they seem to be chatty on a lot of new 4runners.

That said, I dont think the all-wheel drive systems have needle bearings, pretty sure those use plain bearings in the front diff.

 

Ive talked with a few that has the same kit installed and they do not have any issues. They do have 15 year models though.. .Would it be possible to remove the front drive shaft to see if noise goes away while driving? I wasnt sure it that's possible with it being AWD

 

Post some pics of this rig

 

Any chance you can post a video?

Like @McSpazatron mentioned, I wouldn't rule out the needle bearing. Plenty have been bad on stock trucks.

I'm not sure if the differentials are the same or different. I don't see why they would be, though.

 

If IRC, I think the front diffs on the AWD limiteds only has plain bearings instead of the needle

 

Weird. I wonder why.

 

Because Toyota “dared to care”for the limited customers.

I read the plain bearing thing on the internet, and it’s always right.

 

Don’t see why it would be a issue, it would just be 2 wheel drive since the main power comes from the rear wheels.

 

not sure. I thought the transfer case was open in the limited (I could be wrong though). If that’s the case, then I would think removing a driveshaft would simply stop the vehicle completely, as all power would transfer to the “wheels” with the least resistance.

 

Hm, I suppose only way to find out would to just give it a try. I figured they drove in 2 wheel drive until slip / different wheel speed occurred which would then send power to the front as well. It’s obvious not a Toyota but that’s how my grand Cherokee with awd Quadra drive worked.

 

Rear driveshaft slip joint is overextended?

 

4 WD Runners do have needle bearing. And it will manifest in 2 WD mode only since it's job to support left axle while front diff is disconnected.

 

This is something I would definitely look at!!! Also, I dont know how those bracket lifts work, but if they lift the rear just by using taller springs or spacers, then you’ll have all look at U-joint angle as a possible source of noise. The clocking of the entire axle might need to be looked at, as well as its fore/aft positioning. Not if that was addressed in the OPs lift.

Pics would help, and also it would be cool just to see.

 

The OP has a limited. Those have a different 4wd system (its technically all wheel drive). Im not an expert in them, but Im almost positive the internet told me these Do Not have the loud needle bearings that are problematic in the 4wd systems of the SR5, Off Road, and Pro trims. So if I were the OP, I would verify this before chasing crazy gooses.

 

I appreciate the responses. Looking at both the front and rear drive shaft the yoke appears to be more extended than before. I will get pictures and videos to post

 

Pump a bit of extra grease into it to see if you notice a difference. Actually, maybe even do it diagnostically and do one zerk time, then test drive it. Because, on the off chance extra grease does quiet a joint down, you would know which one it was…. That might take a bit of patience, but if it works it would reveal where the problem is.

So, question was your lift in the rear done with just springs/spacers? Did the kit include properly sized panhards, drag bars, etc? Or are all those still stock?

When you get a chance to take pics, take a clear one -squarely side on view- that has a view of the entire wheel well, or the whole side of the vehicle if possible. This can help visualize how centered the axle is fore/aft in the wheel well.

Also take a pic squarely dead center from behind, showing both wheels, in order to see how centered the axle is laterally.

I hope my questions dont imply Im an expert (this is my first 4x4). But Im pretty sure if you can visibly see anything off centered, you are probably going to need new link, bars etc, maybe even need to weld on a new bracket for the side to side link (i think thats the panhard…it needs to be as close to parallel with the ground as possible). Another thing…if the noise is the slide yoke…that could mean it’s getting close to it’s extension limit, which Im just going to assume that’s a bad thing that will also need to be addressed.

 

The dealership said I had a bad pinion angle at the front drive shaft

 

How would I begin to adjust the front pinion angle? The kit came with everything i thought I needed to get everything back to spec after lift

 

This is what the kit came with plus the rear lifted shocks

 

I greased the u joints but unfortunately it did not change noise. I did try to remove front drive shaft but it didn't go into gear. Assuming it's awd I kinda figured it wouldn't. As far as the back, it's lifted with springs, extended sway bar links, extended track bar and brake line brackets. After taking back pic, it looks as if it's sitting to the left

 

So you guys installed a diff drop right? How much did it drop? I have heard that diff drops improve CV angles, at the expense of pinion angles, so that diagnosis might be in track if you have a substantial diff drop.

Maybe somebody on here knows, but that almost sounds like you might need to clock the front diff to better meet the front driveshaft, if that’s even a thing. I am literally taking out of my ass right now though…

Have you called the lift kit company to talk it through with them? I would get their thoughts first.

After that, I’d try to find dedicated off road shop that deals with 4x4s. Maybe there is a solution to improve pinion angles. Also, they can give you an opinion on locating the rear axle if that is needed.

 

Is any of this Pro Comp 6" lift reversible, as in is there cutting or welding in the installation? For the life of me, I just wonder how this much lift was decided on, and why not something in the 2"-3" range, which seems so much more reasonable...

OP, I hope you find the solution to this issue. I'm curious as to what directed you to the Pro Comp lift...even though 4WP's online store likes to tout the wonders of this lift, it's pretty much 99% about lifted Jeeps. I can tell you as one who came from the Jeep world after 30+ years there, Pro Comp is one of the last lifts a serious Jeeper would install.

I hope the solution to your issue isn't ditching this lift and spending your lift money all over again.

 

That’s one hell of a spacer lift.

I have a much smaller spacer lift with diff drop and have not experienced any pinon angle issues.

Years ago I had new rear leaf springs installed on my 97’ Tacoma and they were overarched. This led to an extreme pinon angle that had symptoms similar to what you’ve described.

I didn’t make it one block from the leaf spring shop and I turned around and took the truck back. They pulled the springs and flattened them out and life was good after that.

I’m not a suspension expert, but with that big a lift, I’m guessing you’re gonna be chasing driveline issues.

Best wishes.

 

just reread this…yeah, probably for sure your angle going into your front diff is too much.

If you mean you dropped it to factory location relative to the CV joints, then the all of the brunt of that angle change is being taken up by the front driveshaft/pinion.

Just spitballing here, but maybe if you raised your diff by half as much as it came down. Your cv angles would get worse, but your front pinion angle would get some relief. It might make both bad though…