Shaking / Rumbling

[paulbrapp]

Need some help with this one!

I have a 97 disco I and it has about 120k on it. The other day it started. When I excellerate my whole truck shakes. It happens no matter how fast I am going. I can pull out fine but shortly after I get a lot of shaking.... Stops when I let off the throttle and coast so I don't think it has anything to do with my alignment. I thought it could be a motor mount but I took a look under the hood and they seem to be intacted.

I am open for anyones suggestions!

Thanks in advance

 

[Justin Kurosaki]

Driveshaft

 

[barefoot]

u-joint.....stop driving it til you get it fixed! if a front one goes while your driving it can take out the transmission! if rear one goes it could take the gas tank!

crawl under and take a good look at your u-joints...if its not obvios which one is bad take off the drive shafts one at a time. you have to lock the diff before you do this! drive around and see which shaft being removed stops the vibes....that will be the suspect shaft-replace the joints!

presicion #344 @ napa for $20
there is also one at advanced that some say is stronger and cheaper....you will have to do a search for the part#

enjoy!

 

[paulbrapp]

Thanks guys... Is that a hard job replacing the U-joints - driveshaft?

 

[barefoot]

if your mechanically inclined...it is easy!

drive shaft has 8 bolts holding it on....remember to lock diff first!

for u-joints
remove the driveshaft
remove 4 c-clips per u-joint
usning 14mm or so socket...hammer joints out
once youve got one hammered out youll be able to figure out how to remove

put new ones in same way...be careful with the caps! if one wont hammer all the way in enough to get c-clip on you have prob smashed a needle bearing

buy an extra u-joint when you get the others as you will prob screw up a needle bearing!

none of this may make any sense to you now....but it will all be obvious when the parts are in hand!

enjoy!

 

[paulbrapp]

Right on thanks

 

[walsnart]

Also check the rotoflex (97's still had em right?), this can cause some serious vibes if its getting worn out real bad.... mine is.

 

[barefoot]

walsnart is right....i would start with the rear shaft if you still have a rotoflex joint (big black rubber thinggy on the drive shaft) you can take a look at it. if you see cracks in the rubber....its probably bad! just remove the shaft and drive around!

if your roto is bad....you may want to look into updating to a u-jointed rear shaft! try searching this forum for more info oin this...

enjoy!

 

[paulbrapp]

I just looked under my truck and the rotoflex joint is the problem. It has cracks and frays all around it. Where can I get a replacement cheap or should I go some other route?

 

[barefoot]

still...take that rear shaft out and drive just to be certain! you dont want to screw around with u-joints!

if you are not going to put lift and bigger tires on eventually.....then it would be ok-ish to just replace the rotoflex. however, they are a high fail item! meaning-they go bad frequently. if you decide to keep it on there...be sure and get oem...they are around $80 as opposed to the $40 replacements that wear REALLY quick!

if you plan on lift/tires. it would be in your best interest to update to a fully u-jointed shaft like the front shaft has. i got mine updated using a used shaft out of a rrc. add the 4-bolt flange and spacer and i think it was prob $150-125 or summin. if you go this route...send will or jammer a pm or post up in the parts wanted section! great basin rovers has them new...but more expensive!

enjoy!

 

[paulbrapp]

What are the parts I would need to change to a rear ujoint instead of the flex? How difficult.... I am not the greatest mechanic.

 

[paulbrapp]

Just took my truck for a ride. Lock the differential and the problem was gone. What does that mean? Is the flex joint the problem then?

 

[walsnart]

Did you remove the rear shaft and drive with the lock on (front wheels only getting power)? If so, then yes, the rear shaft was the culprit.

As for changing to a u-jointed rear shaft... Go to the tech section on this site and look for Rotoflex to U-joint Conversion, it answered alot of questions I had regarding this swap.

 

[paulbrapp]

No I did not remove the rear shaft

 

[paulbrapp]

Hey guys I thought the problem went away when I locked the differential but I just tried to go somewhere and the damn thing is doing it again. So I unlocked the differential and it stop... Now what?

 

[Justin Kurosaki]

You are going to need to lock it and pull one of the driveshafts. Give it a good run around the block. D1's tend to have the roto's go bad (rear) while the D2's tend to have the front U's go. Start with pulling the rear.

-justin

 

[Justin Kurosaki]

And take barefoot's advice.. Be sure to get it fixed quickly. A broken U-joint can really wreak havoc under your truck. $$$$.

 

[paulbrapp]

Thanks Justin - I am going to pull it apart tomorrow and see what the damage is. I already can see that the flex joint is bad just by looking at it but wasn't sure if there was more wrong or not. I guess I will find out tomorrow.

 

[bodhizattva]

Pull both driveshafts, bring em to a truck parts place and have them rebuilt and balanced.. I just did mine, think it was $230 or less? They put on serviceable ujoints too...

Don't forget to pick up new locking nuts from your dealer for a few dollars, its a good idea to repalce those nuts and not reuse the old ones, worth the extra insurance...

cheers..

 

[paulbrapp]

Here is an update.... I replaced the flex joint and the problem seemed to have gone away. It has been about 2 weeks now and I still get some shaking here and there but not like before. Any ideas as to what else I should check out?