2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Rear End Vibration - need help diagnosing

Thread Tools
 
Search this Thread
 
Old 12-09-01, 10:32 PM
  #1  
Full Member

Thread Starter
 
Join Date: Dec 2001
Location: Ohio
Posts: 66
Likes: 0
Received 0 Likes on 0 Posts
Rear End Vibration - need help diagnosing

O High Priests of the Rx7,
I have a vibration that is coming from the rear end as far as I can tell. Probably from the middle or right side. I thought it was tires or a bent rim so I just put some used rims and tires on and it still shakes. It is a very minor vibration and it is directly proportional to the speed of the car. Engine can be at 7000 or idling. I don't know what else it could be. The drive shaft and axles seem to spin nice and smooth from running it on the rack. This is my first second gen and I'm totally out of ideas

Please Help
Old 12-09-01, 10:39 PM
  #2  
Full Member

 
mazdaspeed's Avatar
 
Join Date: Nov 2001
Location: Calgary,Canada
Posts: 117
Likes: 0
Received 0 Likes on 0 Posts
How many kms on the car? I had a 83 RX7 that did that and it ended up being the bearings. Im not sure if that is your problem because i could very easly be wrong, but just a guess.
Old 12-09-01, 10:43 PM
  #3  
Junior Member

 
Join Date: Oct 2001
Location: Space
Posts: 34
Likes: 0
Received 0 Likes on 0 Posts
Talking

Could be many things but here is a quick list of things to check.
1) Bad u-joint on driveshaft or axle
2) bent driveshaft or axle
3) loose driveshaft or axle
4) Worn bushings on rearend
Hope this helps!
Old 12-09-01, 10:53 PM
  #4  
Rotary Enthusiast

 
rx7_ragtop's Avatar
 
Join Date: Mar 2001
Location: Ft. Worth, Texas, USA, Earth, Solar System...
Posts: 1,273
Likes: 0
Received 0 Likes on 0 Posts
does it make any noise? Does it change with throttle setting? (ESPECIALLY if it changes dramatically going from light throttle to deceleration)

Probably your driveshaft. It's a very common failure. The u-joints in a stock one are NOT replaceable, but the Mazdatrix aftermarket ones are. Check to see which you have of course.
Old 12-09-01, 10:53 PM
  #5  
Full Member

Thread Starter
 
Join Date: Dec 2001
Location: Ohio
Posts: 66
Likes: 0
Received 0 Likes on 0 Posts
How can I tell if its a drive shaft or axles. I have grabbed onto the u-joints and tried to jerk them around and they won't budge. The car only has 80,000 miles on it as far as the odometer says. The idiots at Midas told me it was a bad differential. Is there any possibilty of that? I have access to a shop and a lift but I don't really know what I'm looking for at this point.
Old 12-09-01, 10:58 PM
  #6  
Rotary Powered

iTrader: (2)
 
Rx-7Addict's Avatar
 
Join Date: Sep 2001
Location: Chicago, IL
Posts: 2,272
Likes: 0
Received 1 Like on 1 Post
rx7ragtop:

Are you talking about light throttle and then letting off?


when I am on the highway I will be cruising around 3500 - 70-75 and when I let off the accel it makes a loud harsh rubbing noise? What is this ?
Old 12-09-01, 11:03 PM
  #7  
Full Member

 
Mazda2ndgen's Avatar
 
Join Date: Mar 2001
Location: bradenton, fl usa
Posts: 123
Likes: 0
Received 0 Likes on 0 Posts
just b/c your ujoints are not loose on your driveshaft doesnt mean it cant be messed up. i just fixed and INSAINE vibration in my car. while acclerating the whole car felt like it was aobut to fall apart, and even with the clutch in the car would vibrate pretty bad. i happen to have a spare drivshaft, so i swaped out driveshafts and it fixed the problem completly. the ujoints on my driveshaft are perfect, absoltly NO slop. I have no idea what caused it to go bad.. maybe it threw a weight off or somthing, i have no clue...
Old 12-19-01, 04:30 AM
  #8  
It's Whatever

 
Prowla RX7's Avatar
 
Join Date: Sep 2001
Location: Ft Laud, FL
Posts: 105
Likes: 0
Received 0 Likes on 0 Posts
how much would it be to replaced the driveshaft, and whats the best way to go about it as cost goes... not meanin to be cheap, but yet effective? i can feel it vibrating in my car also... when i hit higher speeds like 80+ my car gets shakey, and i just had my tires balanced and aligned about 3 months ago... i dont think it could get outta realignment that quick.
Old 12-19-01, 07:09 AM
  #9  
Senior Member

 
t_mak@mail.plymouth.edu's Avatar
 
Join Date: Jun 2001
Location: Norwich CT
Posts: 307
Likes: 0
Received 0 Likes on 0 Posts
Does it come from the front of the car or rear? If it is front, check the balanciing again

Townfair tires claimed they ddi my tire. I checked the leds on it, guess what, still the old ones
Old 12-19-01, 04:32 PM
  #10  
Full Member

 
BhamBill's Avatar
 
Join Date: Feb 2001
Location: Bellingham, WA
Posts: 242
Likes: 0
Received 0 Likes on 0 Posts
Mine was a bad CV joint. Pick up some rebuilt rear axles. It's not too tought to replace them.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Th0m4s
Build Threads
25
02-26-19 02:04 AM
coltboostin
Rotary Drag Racing
0
08-20-15 11:37 PM



Quick Reply: Rear End Vibration - need help diagnosing



All times are GMT -5. The time now is 11:39 AM.