Mhelvestine

Under load bad vibration at 60+ Changed out lower ball joints because they were bad , no change, Installed new sway bar bushings those too were bad, no change. Checked out u-joints all good no play, kinda at a loss here trying to figure out what's it might be. Even rotated tires no help. Did notice today that the 4 wheel drive didn't engage. Checked out the CV joints no play. and no play in the tires so bearings are good.

TacoTank

If it didn't engage, is it possible it got stuck in 4WD? Do you have auto-locking hubs?
Another option is driveshaft alignment, are you running any kind of lift or leveling stuff?

Mhelvestine

No lift, I too was thinking that the 4 wheel drive is the issue.. I only have the lever next to the gear shift inside the truck.

TacoTank

Ok so no auto-locking. You have manual-hub 4WD. Turn the hubs back and forth, see it they're locking, stuck, or won't click into place. One might not be all the way into position or broken and need new hardware.

Mhelvestine

No I don't have locking manual hubs. All I have to do is pull the lever inside the truck to engage 4 wheel drive. Sorry for the confusion.

TacoTank

Is it the type of shifter with the 4WD push button on the side?

Mhelvestine

no the 97 model only have the lever no buttons. mike

TacoTank

Was not aware of that. Either way my guess is still going to be something up with the 4WD system itself. If it was auto it would have electrical sensors that can go bad. If not then it sounds mechanical. I'd suggest popping the wheel off and checking out the hubs, see if anything is broken or stuck.

ricky

Have you checked driveline angles and u-joints? I've had issues where u-joints were bad, causing vibration ONLY under load.

Mhelvestine

I posted a thread back in November, Still having this vibration at 58- 70 but it eases up a little at 70. Also noticed that the 4-wheel drive light on the dash doesn't come on when I engage the front axle. This 97 has a lever that I have to pull back for the engage and don't have locking hubs. I did a little test on it the other day, while moving very slow I pulled back on this lever to engage the 4-wheel drive and I could hear the gears trying to engage but it was grinding because I was moving. This tells me that the transfer case was trying to engage, I don't think that the front axles are engaging though. I plan to lift the car off the ground and see what is going on. This vibration at 60 is like a roar, also noticed when I let off the power it stops, but when I try to accelerate, it is there as soon as I push on the gas. Any Ideas ? Mike

akwheeler

Most vibrations that come and go with the throttle are caused by rear driveshaft u-joints, slip yokes, CV (double Cardan joints) or rear differential issues. Check all of these for play up/down side/side or rotation when the truck is in neutral wheels chocked or e-brake on and in 2wd. if you don't find anything check the driveshaft phasing (all the u joint caps line up basically) if your driveshaft has ever been removed or new u joints put in it may have been reinstalled improperly, but this would probably vibrate ALL the time. Also rear diff lube for level and condition, maybe drain it out and check for metal flakes.

Mhelvestine

I too thought that it was a U-Joint issue also, all were tight and no play even greased the joints to see if it even made any difference. The drive shafts are in alignment and I checked the rear diff to see if the lube was low,,,it was not. I was hoping to find something no metal flakes in lube. I think the next thing that I am going to do is jack stand the car off the ground and (with no one around the car) I am going to take it to 60mph, and see if the vibration is still there. If not the problem has to be in the front end. I had just changed out both lower ball joints and sway bar bushings, it too made no difference. Mike

akwheeler

If the shaking stops when you let off the throttle you are not likely to duplicate it with the truck on jackstands, no load on the drivetrain. If shifting from 4wd to 2wd on your test drives didn't change the vibration it is highly unlikely that anything in the front end is causing it. Did you check your slip yoke for play?

Mhelvestine

The yokes had no play, the driveline is tight from one end to the other. Even went a bought a u-joint thinking that was the issue.....at least I now have a spare. Trying to find someplace where they dyno so I can keep the car on the ground and still check it. Will keep everyone posted. Mike
PS I will find out what's causing this.

Co_94_PU

iTrader: (-1)

Much like improper alignment of the yokes the pinon angle miss matched to the output will create shaft speed variations. This would be due to worn bad leaf springs, in this case bad bushings or a bent arm or something coming loose there.

Mhelvestine

That's a thought didn't think about that I will check it out today thanks. This four runner has 400,000 miles on her . She has been a very good truck. Mike

maco35

My truck used to do the same thing vibrating as soon as i let off the gas pedal all the time, all of a sudden pinion oil seal starts leaking so i replaced it, and when i
put the pinion nut back on i tightened it one 1/4 of a turn more than where it originally was and the vibe went away when letting off the gas pedal.

And yes i counted how many turns it took to take the stake nut off the pinion and now my truck feels nice and smooth now when coasting on the freeway. It's just an idea not saying that's your problem.

Mhelvestine

Thanks for that info, I will check today. also I am going to run my hand around the driveshaft to see if I feel a welded spot with nothing on it. I know that the driveshaft is balanced and I will check to see if a balance weight came off. This truck just turned 400,000 mikes day before yesterday. Thanks for all your help. Will keep everyone posted as we figure this out. Mike

Mhelvestine

Hello again, it's been just about a year since I had an issue with my 1997 4-runner which now has 422,000 miles on it. Here is the latest problem....First start in the morning, fires right up . drive until the temp gets to operational, cut the car off , come back out and restart, seems to have to crank a bit longer to catch, then it starts, and even then I need to keep the starter engaged for a couple of seconds then it starts. Almost everything on this is original. Just replaced the fuel pump a couple of months ago that too was original. Mike

Discombobulated