85 Suburban vibration??? - Off-Road Forums & Discussion Groups
GM Standard SFA Trucks & SUV's All discussion of full sized Solid Front Axle Trucks, SUV's to include Suburban

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 11-01-2002, 07:27 PM
**DONOTDELETE**
Guest
 
Posts: n/a
85 Suburban vibration???


Hi guys. I own a 85 GMC Suburban 3/4 ton two wheel drive. It has the 400 transmission and a 454 motor. It has a oscilating vibration at about 67 m.p.h. on up. I feel it in the floor and in the seat. I can run it up to 70 m.p.h. and take it out of gear and it stops. When stopped I can put the truck in park and get the r.p.m.'s up to where they were at 70 m.p.h. and there is no vibration. I can put the truck in 1st or 2nd and get the r.p.m.'s up to where they were at 70 m.p.h. and there is no vibration. I have put new U-joints and carrier bearing on it and it still has the vibration. I have looked at the drive shaft for a thrown weight and did not see anything. I put a new transmission cross member rubber mount on it. I also put a new fan clutch on it. I rotated the tires to see if the vibration changed location. It didnt. I've been trying to pay closer attention to where it is coming from and it feels like it may be toward the rear of the truck. What can I look for in the rearend.
I bought the truck like this thinking it was the U-joints so I don't know how long it has had the vibration. Man if you could help me out here Id be very thankful!! Mark


Sponsored Links
Advertisement
 
post #2 of (permalink) Old 11-01-2002, 08:38 PM
87sm465np208
Guest
 
Posts: n/a
Re: 85 Suburban vibration???

my 10 bolt yoke bolt was loose, try tighting that up, mine would vibrate really violently when i came to a stop.
post #3 of (permalink) Old 11-04-2002, 08:18 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: 85 Suburban vibration???

I have the same rythmic pulsating vibration that happens at highway speeds (no speedometer). Mine only started after I put a TH400/ NP241 and changed nothing else. It didn't have that vibe with the 700/NP208. My dads onl '79 2wd chevy with a TH400 did it too and my G/Fs folks '98 burban with a 350/700/NP208 does it too. I have yet find an answer for it. Some posible theories might lay into the torque converter weight problem or something don't know.
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 11-08-2002, 09:49 PM
 
Join Date: Nov 2002
Posts: 144
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: 85 Suburban vibration???

have you checked your u-joints yet that is what mine did before i ripped it out for a 350
aahomerepair is offline  
post #5 of (permalink) Old 11-11-2002, 07:45 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: 85 Suburban vibration???

If you are uncertain about your drive shaft, or if you replaced u-joints, then you need to take the whole thing from one end to the other to a shaft balance shop that will spin balance the entire shaft as it runs on the truck. Cost here is about $45 and well worth it. This is recommended every time you even just install u-joints, although most don't do it.

Mike
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome