low speed vibration - Great Lakes 4x4. The largest offroad forum in the Midwest

Go Back   Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > Chevy Tech
GL4x4 Live! GL4x4 Casino

greatlakes4x4.com is the premier Great Lakes 4x4 Forum on the internet. Registered Users do not see the above ads.
Search
Reply
 
Thread Tools Search this Thread
Old May 31st, 2010, 05:27 PM   #1
tctrojan17
Sexy and I know it.
 
tctrojan17's Avatar
 
Join Date: 05-21-10
Location: traverse city
Posts: 888
iTrader: (5)
Mentioned: 0 Post(s)
Default low speed vibration

I tried searching and could not find what i needed. Anyways...

I have a 94 full size blazer with a solid axle swap done to it and about 12 to 14 inches of lift to it. I just put a set of 37 inch hummer take offs on it and i get a pretty bad vibration/hopping at low speeds up to about 25 mph. After 25mph it smooths out and seems alright.

The tires are not balanced but i assumed that would cause high speed shimmy's not low speed ones. Any ideas.

I also get a grinding sound coming from what appears to be the tcase when ever i am coasting. It does not do it at low speeds only like 30 and over. The grind sounds just like a manual tranny does when you grind the gears. I have a pretty steep rear drive shaft angle and i have read that can cause this. What exactly is making the noise if it is my drive shaft angle. I have had this truck to a few wheeling events and it did not make these noises with my boggers on, or i just did not notice it.

Thanks for any input.
tctrojan17 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old June 1st, 2010, 10:37 AM   #2
tctrojan17
Sexy and I know it.
 
tctrojan17's Avatar
 
Join Date: 05-21-10
Location: traverse city
Posts: 888
iTrader: (5)
Mentioned: 0 Post(s)
Default

I noticed today it does not make the grinding noise with rear drive shaft out, or with t case in nuetral. I am really wanting to lean towards it being my tcase but the noise sounds like it is coming from the drive shaft itself. It is hard to tell if it is traveling from the tcase or not. My u joints appear good. Where my slip on my drive shaft goes into the t case there is some play inside the tail shaft. Is that normal?
tctrojan17 is offline   Reply With Quote
Old June 1st, 2010, 05:20 PM   #3
Yetti
Buy a Fiat! Save the UAW!
 
Yetti's Avatar
 
Join Date: 11-05-05
Location: 20 minutes south of Hell...
Posts: 14,385
iTrader: (10)
Mentioned: 2 Post(s)
Default

since this isn't my truck I can only suggest things. the first thing to rid yourself of is the slip yoke. if you don't have a proper driveline angle the drive shaft is going to bind at a point its under the most load. mainly the slip yoke. slip yoke eliminators replace the output and give you a fixed yoke on the T case. then you get the benefit of the slip yoke in the driveshaft and if its steep enough angle a Cartagan joint in that shaft to help fight the extreme driveline angles.
secondly if you didn't re-clock your T case that could be adding the tight angles.

just remember at low speed torque is the enemy. it can and will find your week link and make it work against you.
__________________
Yetti
Yetti is offline   Reply With Quote
Old June 1st, 2010, 05:52 PM   #4
chadcooper55
expert jeep disassembler
 
chadcooper55's Avatar
 
Join Date: 08-28-08
Location: kent city mi
Posts: 8,033
iTrader: (20)
Mentioned: 11 Post(s)
Default

i was getting alot of low speed vibrations on my jeep and it ended up being a broken tranny mount. as soon as i got up to speed (45-60) it was fine, but for 0-45 it vibrated BAD! I sounds like you have alot more going on than i did but a tranny mount is easy to check. good luck
chadcooper55 is offline   Reply With Quote
Old June 1st, 2010, 07:04 PM   #5
tctrojan17
Sexy and I know it.
 
tctrojan17's Avatar
 
Join Date: 05-21-10
Location: traverse city
Posts: 888
iTrader: (5)
Mentioned: 0 Post(s)
Default

Well i just checked my tranny mount and it is junk so i am getting a new one tommorow. I have not dealt with the slip yoke because this was originally built to go down the road and go through light mud holes. So I figured why put the money into dealing with that. But now i decided to run it like it is for a year while i finish collecting everything i need for putting rockwells and a big block in her.

So the slip will be gone soon enough just not this year. Right now i have my pinion pointed directly at the t-case in the rear. I think you only do that with a cardagan joint but if i make the angle of the pig on the axle the same as the t-case there is binding.

As of right now i think the noise is coming from the drive shaft, i tore the t-case apart and also swapped it, looked at my rear axle and everything looks good. It sounds like bb's in the drive shaft tumbling around. Do you guys think that bum trenny mount could be causing this noise as well?
tctrojan17 is offline   Reply With Quote
Old June 1st, 2010, 07:09 PM   #6
Yetti
Buy a Fiat! Save the UAW!
 
Yetti's Avatar
 
Join Date: 11-05-05
Location: 20 minutes south of Hell...
Posts: 14,385
iTrader: (10)
Mentioned: 2 Post(s)
Default

Tranny mounts can do all kinds of weird things. get it replaced and see whats fixed.
__________________
Yetti
Yetti is offline   Reply With Quote
Old June 1st, 2010, 09:32 PM   #7
tctrojan17
Sexy and I know it.
 
tctrojan17's Avatar
 
Join Date: 05-21-10
Location: traverse city
Posts: 888
iTrader: (5)
Mentioned: 0 Post(s)
Default

Will be doing that tommorow. thanks for the help guys will let you know how it goes.

Yetti what exactly did you mean by clocking the transfer case? Like getting a clocking ring?
tctrojan17 is offline   Reply With Quote
Old June 3rd, 2010, 01:28 PM   #8
tctrojan17
Sexy and I know it.
 
tctrojan17's Avatar
 
Join Date: 05-21-10
Location: traverse city
Posts: 888
iTrader: (5)
Mentioned: 0 Post(s)
Default

tranny mount replaced and it is still making the horrible noise the low speed vibration is less noticeable. I did find out today that my drive shaft is ever so slightly bent like an s more or less. On a lath it is shown as good in the middle and ever so slightly off on the ends. I hate to drop 300 big ones right now with out knowing it will solve the issue at hand. plus i would think that would cause bad vibrations at high speeds which i do not have so i am unsure if that is causing my drive line rattle. Any thoughts?
tctrojan17 is offline   Reply With Quote
Old June 3rd, 2010, 01:42 PM   #9
BigBlockBlazer
Axle breakin' 101
 
BigBlockBlazer's Avatar
 
Join Date: 10-08-08
Location: Traverse City, Mi
Posts: 2,342
iTrader: (12)
Mentioned: 0 Post(s)
Default

Spend the money and have a driveshaft made with a cv on the slip end and it will more than likely go away. If not, you now have a reliable drive shaft.
BigBlockBlazer is offline   Reply With Quote
Old June 3rd, 2010, 01:44 PM   #10
BigBlockBlazer
Axle breakin' 101
 
BigBlockBlazer's Avatar
 
Join Date: 10-08-08
Location: Traverse City, Mi
Posts: 2,342
iTrader: (12)
Mentioned: 0 Post(s)
Default

Why are you running 14" of lift with 37's?
BigBlockBlazer is offline   Reply With Quote
Old June 3rd, 2010, 06:46 PM   #11
tctrojan17
Sexy and I know it.
 
tctrojan17's Avatar
 
Join Date: 05-21-10
Location: traverse city
Posts: 888
iTrader: (5)
Mentioned: 0 Post(s)
Default

Well new crap to toss into the mix here. I tried lowering the whole truck so that the drive line angle was in good standing and the pinion angle and transfer case angle were what they should be and the noise is still there.

I am looking at a cv drive shaft but hate to spend the money for a summer fix that may or may not work since in the fall rockwells and a big block or going on her.

It did not do this with my boggers on it while i was taking it offroad or when i reached decent speeds on dirt roads and would coast. My tcase got ripped in half at an event and i put a new one in and have never had it up to high speeds till now. I rebuilt the tcase and it still is making this noise.

I have a hard time wanting to believe it is the drive angles if it did not do this before and that when i corrected the angles it still was doing the noise.

It has 37s on it because they were cheap and run down the road good and it was originally built for that, but as you can see after one wheeling event i decided to go a different route. which is why the rocks and big block will go in her in the fall.

I am about sick of working on the truck at this point. I am going to try a different drive shaft since mine has a slight bananna bend in it but the guys at the local driveline shop said it is so minor they would not see it causing that noise.

Any more ideas before i either drop the bucks for a cv shaft or just tear i apart and proceed with my plans earlier.
tctrojan17 is offline   Reply With Quote
Old June 4th, 2010, 12:06 PM   #12
tctrojan17
Sexy and I know it.
 
tctrojan17's Avatar
 
Join Date: 05-21-10
Location: traverse city
Posts: 888
iTrader: (5)
Mentioned: 0 Post(s)
Default

Sorry s shape bend not banana. It looks like a different straighter drive shaft more or less got rid of the noise when actually driving, with the truck on stands though it still makes it but i can live with it for the next few months if it does not do it while driving.

Still have this low speed skip though. Tires are radials and rims are new. It did this with my boggers too, but i expected it with those. It is as if i am going over a bump on my front tire and then immediately going over another one with the opposite rear tire. It goes away at about 15 to 25 mph.
tctrojan17 is offline   Reply With Quote
Reply
Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > Chevy Tech

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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

Forum Jump


All times are GMT -5. The time now is 05:43 PM.


Powered by: vBulletin, Copyright 2000 - 2012, Jelsoft Enterprises Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
Page generated in 0.17856 seconds with 56 queries