[20bugsys]

I have a 98 4x4 tacoma w/ 5 speed and 2.7L 4 cyl. w/162K. Since I bought the truck in August, there has been an audible rattle from underneath the truck. It was most noticable with the rear window slider open.

About a month ago, I replaced the manifold exhaust gaskets, making the rattle sound even more pronounced now that it isn't drowned out by the loud exhaust.

The sound is louder if the engine is under load. It is RPM related, coming on around 2500 - 3000 rpm. I'm ruling out drivetrain, because I hear the sound if the truck is standing still and I rev the engine and hold it at 2500.

At first I thought it was u joints until I noticed it rattles without the truck moving. I've checked and repaired all of the heat shield rattles, and removed both underpan shields to aid in diagnosis.

The muffler is beginning to rust out on the bottom.

So I am now thinking it is either baffles inside the muffler, or timing chain tensioner.

I'm leaving next Thursday for a 1500 mile trip to Vermont. If it is timing chain tensioner, will I make it there and back?

Any other ideas?

 

[rugerm44]

Timing chain tensioner on mine went out but it didnt rattle.It made a grinding noise.I took off all of the drive belts and could still here it.Take a long screw driver and hold to different spots on the front timing cover.Then hold the handle up to your ear.Thats how I spotted the problem.I drove to OK and back and when I returned I noticed it was louder than when I left.Also had a bad water pump seal.All this with 20,000 miles.It was fixed under the power train warranty.

 

[20bugsys]

Yeah, it could actually be described as a grind. That's why I thought it was drivetrain related first.

 

[rugerm44]

Sometimes a drive belt can make a strange noise.Thats why I just took them off to elminate the belts making the noise.With that many miles could be the tensioner.I told you timing chain tensioner on mine.I made a mistake there mine has the timing belt.My mind is on something else.I went to the doctor for a check up and he told me I have a hernia of all things.Getting old sucks.Im trying to figure out when Im going to have that fixed.Not looking forward to it.Couldnt have had it very long or I would have noticed it before now.Oh well 45 next month I guess other things will start falling off next.Have a good one.

 

[lancekilgore]

Ok try checking all your heat shields to see if any are loose. grab them prefably while cold. and see if there is movement. simple fix remove the loose one or put a huge hose clamp on it and tighten down.
hope this helps

Lance

 

[02TAC]

Is it RPM or speed related? does it make the sound at the same RPM or is it only at certian MPH? If it is the same RPM in every gear you can rule out most fo the drive train. If you have access to a lift you can put it up and run it to help isolate the rattle.

 

[TcmaBoy]

Alright, so we have RPM related rattle. Makes noise when truck is not moving. Skid plating has been removed. Heat shields and exhaust leaks have been checked. 2.7L with a lot of damn miles.

Has the timing chain been replaced on this truck, and was the tensioner done at that time? Could be chain slap.

 

[20bugsys]

Just put another 700 miles on this weekend going up to the Upper Peninsula. The rattle seemed to be getting louder but that might be because it was all I could think about while driving 6 hours each way.


Here is a big clue. I stopped at a rest area and parked. My girlfriend sat in the drivers seat and held the throttle at around 2750 rpm, right where the rattle comes on the loudest. I then proceeded to walk around the truck and push on things with the long jack handle.

As soon as I pushed it against the main DRIVE SHAFT, the rattle stopped. So I'm back to thinking U joints. I'm going to crawl around anderneath tomorrow. Any tell tale diagnostic tips for u joints? Like I said in the original post, it makes the sound while moving and standing still. When the truck is moving, it makes the sound over a small range of rpms and speeds, above 2000 rpm and after reaching, say 30 mph. When it's NOT moving, it makes the exact same sound between 2500-3000 rpm standing still.

As far as the timing chain goes, I don't know if it had been replaced or not. I bought the truck last August with 156K on it. I heard the rattle then, only when I had the rear slider window open, but it wasn't as loud then as it is now. I'm leaving in three days for Vermont. I'll have all my tools and my creeper with me.

If I decide to try replacing the ujoints, I'll have a local shop do it before I leave. I just don't have time for that kind of repair without a hoist and a press. I'd like to try to diagnose myself though first.

 

[20bugsys]

I went to the doctor for a check up and he told me I have a hernia of all things.Getting old sucks.Im trying to figure out when Im going to have that fixed.Not looking forward to it.Couldnt have had it very long or I would have noticed it before now.Oh well 45 next month I guess other things will start falling off next.Have a good one.

I had a hernia when I was 29. I think it was motorcycle related. I had a laproscopic surgery done to repair it. I was back to work within a week. My only problem was a serious reaction to the anesthesia. I was so sick, I couldn't keep my pain pills down. Then when I went to the pharmacy for more, they wouldn't give them to me because it had only been a few days. I tried to tell them it was because I kept barfing them up, but they wouldn't listen. Off topic though. You'll get through it.

 

[lancekilgore]

Normally when Ujoints go you get thumping when you drive andif you don't fix ti you will loose the drive shaft. but get under neath the truck grab each ujoint witth both hands just before the joint and shake if you get any type of move ment then it is bad and needs to be changed immediatly. especially if it is the front ujoint if it goes it will act like a wedge and actually lift the truck in the air if it catches any then and do all typoes of damage if it is a rear the it wil just fall to the ground and drag.

Lance

 

[02TAC]

U joints would be speeed, not RPM related. Could be that you put enough of a side load on the drive train that it took the play out of what ever it is. Could be linkage, the mount for your center bearing carrier (if you have one).

 

[20bugsys]

Alright, I took it in today for 3 new u-joints. Once the tech got the shaft off, he realized that the u joints were fine, but that in the front portion of the drive shaft itself, the ball in the CV-like part had a flat spot, which is what is causing all the noise. This makes perfect sense to me, explaining why the noise is so loud from the rear slider window.

He then took the shaft to a local drive shaft fabricator, who said he could repair it, but didn't know exactly when it could be done, or exactly how much it would cost until he got it all apart.

Dealer wants $900+ for the drive shaft assembly new.

Local salvage yards can get one, but don't have one in inventory. Again, can't guarantee "when" they'll have it, but the best price for a used one with no warrantees or guarantees is $225.

I'll keep looking, but it looks like I'm screwed for my trip that is supposed to start in 2 days.

 

[TcmaBoy]

I hope they aren't just poping in a new one. Something caused that wear. You may have a bad motor or trans mount.

 

[20bugsys]

They're not doing anything. I have the truck now and am searching for a driveshaft. I'll look at replacing mounts too.

 

[20bugsys]

UPDATE:

The part that is worn is the CV ball joint in the front double cardan joint. Here is a write up of how that works.

http://www.rblewis.net/personal/bronco/driveshaft/

 

[lancekilgore]

Thanks for the info, been quite a few threads about that rattle.

Lance

 

[TcmaBoy]

UPDATE:

The part that is worn is the CV ball joint in the front double cardan joint. Here is a write up of how that works.

http://www.rblewis.net/personal/bronco/driveshaft/

Oh, just the double cardan. I though you were saying the trouble was at the trans output.

 

[20bugsys]

Oh, just the double cardan. I though you were saying the trouble was at the trans output.

Yeah, I found a shaft with 50K on it for $120. I had it shipped to my friends place in Vermont. As long as I make it there in one piece, I'll have it checked out and balanced before I install it for the return trip. I can't get one around here in time for my departure. The truck was making this rattle when I bought it 10,000 miles ago. I am just hoping that another 1500 won't break it.

Thanks everyone for your help.