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Old 05-12-2023, 05:12 AM   #1
gmc 2500 4x4
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rear end shudder

im having a slight issue, 69 gmc k2500, all redone, i went from 4:56 gears to 3:54. it now has a bb 402 and original sm465 trans, and rockwell 221. im getting a shudder when slowing down in 2wd, even when i push in the clutch. would the gearing change affect the t/case? has a 4'' lift also, and i did shim the rear axle for driveshaft alignment...
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Old 05-12-2023, 06:39 AM   #2
kwmech
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Re: rear end shudder

Any other description besides 'shudder'? only thing that comes to mind is while applying the brakes
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Old 05-12-2023, 06:56 AM   #3
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Re: rear end shudder

Almost feels like something is binding up with no brakes applied
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Old 05-15-2023, 08:56 PM   #4
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Re: rear end shudder

Do you have a clutch style Posi?
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Old 05-16-2023, 04:48 AM   #5
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Re: rear end shudder

Quote:
Originally Posted by HO455 View Post
Do you have a clutch style Posi?
i do not, i need to jack it up and run it see what i see, this has the carrier bearing also which is new.
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Old 06-02-2023, 09:52 AM   #6
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Re: rear end shudder

i pulled out the degreed shims, also gonna start over and bolt up the rear like its written in my books. its only a 4'' lift so im going to try with out shims
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Old 06-02-2023, 10:53 AM   #7
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Re: rear end shudder

First thougt for me is something is loose or broken. Nut and bolt everything while you're under there. An easy 20 minute sanity check. You shouldn't have to play with angles. Read your angles and shim appropriatly, it's all that's needed. How about those bearings?

j
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Old 06-02-2023, 11:27 AM   #8
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Re: rear end shudder

Rear was all redone, like i said there is a procedure and not sure if I had all tension out of springs and shackles or proper torque on u bolts. It's what happens when u build something and few yrs later u 4get things...lol keep ya posted
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Old 12-23-2023, 07:14 AM   #9
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Re: rear end shudder

when i let off the throttle the pinion angle changes giving me that vibration, been adjusting the angle and seems better. i may use this kit https://www.ebay.com/itm/165624965840, whats yur opinion?
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Old 12-24-2023, 05:32 PM   #10
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Re: rear end shudder

I think you are on the right track looking at u joints. I bet you can reuse your yoke. Also check your center support bearing.
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Old 12-24-2023, 05:38 PM   #11
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Re: rear end shudder

When you decelerate and brake its worse as the pinion is nosing down even more leading me to believe it's binding. I'll get it
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Old 12-24-2023, 08:53 PM   #12
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Re: rear end shudder

Are your spring packs stock with leaf clamps. Also known as rebound clips.

Last edited by geezer#99; 12-24-2023 at 09:27 PM.
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Old 12-25-2023, 08:43 AM   #13
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Re: rear end shudder

4'' lift springs and u bolts
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Old 12-25-2023, 01:10 PM   #14
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Re: rear end shudder

Post a pic of your springs etc.
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Old 03-30-2024, 08:41 AM   #15
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Re: rear end shudder

http://67-72chevytrucks.com/vboard/s...d.php?t=220466 got my answer #25
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