Bad Vibration/Shudder at 45 and 65mph, HELP!

slimsalmon · #1 (**permalink**) 05-13-2007, 07:55 PM

So I recently bought a 98 Tacoma 4x4 and it seems to have developed a bad shudder which is worst at 65mph. Here are the strange symptoms of it though:

Happens regardless of engine RPM, or if the clutch is in or out

BUT: Here is what I think might be a useful clue: if the clutch is in AND I let off the gas, it goes away. If the clutch is out, or the clutch is in and I'm on the gas, it happens with equal severity.

Doesn't anyone have any ideas of what might be the cause? I've lubed the chassis and topped off a low differential fluid level, but neither thing helped.

KdF · #2 (**permalink**) 05-14-2007, 09:34 AM

Quote:

Originally Posted by slimsalmon

So I recently bought a 98 Tacoma 4x4 and it seems to have developed a bad shudder which is worst at 65mph. Here are the strange symptoms of it though:

Happens regardless of engine RPM, or if the clutch is in or out

BUT: Here is what I think might be a useful clue: if the clutch is in AND I let off the gas, it goes away. If the clutch is out, or the clutch is in and I'm on the gas, it happens with equal severity.

Doesn't anyone have any ideas of what might be the cause? I've lubed the chassis and topped off a low differential fluid level, but neither thing helped.

Your flywheel could be cracked..........or......your pressure plate could be cracked as well. Have it checked out quick, as high-speed flying metal never feels good on impact!

wunaswerve · #3 (**permalink**) 05-14-2007, 11:43 AM

could be a cv joint - there's an inner and an outer.

I get the same sort of thing but have ignored it for now.

There's usually a sweet spot where it won't happen.

CV joint replacement isn't too expensive.

SuprWhiteTRD · #4 (**permalink**) 05-14-2007, 05:19 PM

Rotors could be warped. Get them turned & see if that fixes it. Cheap fix if that is the problem.

slimsalmon · #5 (**permalink**) 05-15-2007, 01:52 PM

Those are some good ideas... Normally I would think maybe a tire was out of balance, but it seems like the special case where it doesn't vibrate wouldn't occur if it were that. I wonder if a bad wheel bearing in the rear could be a possible suspect as well.

I think the special case where it doesn't occur might rule out the brake rotors as well as the CV joints. Since I'm only driving in 2wd mode, the rear wheels have the load on them. So when I alternate between gas and not, it shouldn't have much affect on the drive axles and CV joints going to the front wheels (switching to 4wd doesn't have a significant affect on the problem, btw). But who knows.

I hope it's not a cracked flywheel or pressure plate as suggested. I don't know enough about the inner workings of the drive train to know if the special case implies one of those two problems. The reason I'm thinking a rear bearing might be the cause, is because maybe when the motion of the wheels drives the engine instead of the engine driving the wheels, maybe the force in the bearings could be different.

wunaswerve · #6 (**permalink**) 05-16-2007, 06:42 AM

Please check this out:

Constant Velocity Joints, Part 2: Service & Repair

everything you might want to know about cv joints.

Not saying that's what your problem is but failed CV joints will react one way under acceleration, another way with deceleration, another with coasting.

Russ

slimsalmon · #7 (**permalink**) 05-17-2007, 06:30 PM

Arrr... It looks like my rear most universal joint has had one of the pins in it break.

slimsalmon · #8 (**permalink**) 05-18-2007, 06:03 PM

Followup:

A new rear half the driveshaft is supposedly $1100 and it was going to cost another $600 to rebuild/replace all the other deteriorated u joints and center support bearing. I couldn't find any salvaged drive shafts locally (the only two I found were both misidentified and the wrong parts).

But.. Luckily I found this article: Two-piece to One-piece Driveshaft Swap

on converting to a single driveshaft, which gets rid of the spiderweb of failure that is the double cardan/CSB, it cuts the weight in half, and makes the handling more responsive. I called the company which made the one in the article (South Bay Driveline of San Jose, CA) and it is will only cost $350-$500, they have a one day turn around to make it and ship, plus it's total bolt on once I get it.

Ahh, the internet... where would I be without it?

wunaswerve · #9 (**permalink**) 05-19-2007, 06:42 AM

Great article.

So, it looks like the only thing you're giving up is a bit of ground clearance in the middle and this is due to the straight shaft. Sounds like you gain more than you lose.

Will you take some pics of the removal of the old system and the installation of the new system? I look forward to hearing more.

Thanks for sharing the article. Makes me want to go look under the truck right now. Such a geek, I know. haha

Russ

KdF · #10 (**permalink**) 05-19-2007, 02:42 PM

Make darned sure the rear axel is in the correct angle when you go from 2 to 1. I don`t know about Toyota`s dual driveshaft , as my son`s truck is not here now..., but the new Mustangs dual driveshaft when replacing it to a 1 piece needs the rear axel moved a hair to compensate for the difference.

picu · #11 (**permalink**) 05-20-2007, 05:15 AM

try checking universals first they are cheap. i put them in mine for 50.00. my vibration was the same, certain speed