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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Rear Drivelines, Drive Axles and Gearing => Topic started by: MrFiveOh on May 21, 2016, 06:40:30 PM
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First I want to say i have been chasing this vibration for a while and i have refrained from coming straight on here until i tried all i can. So on to the issue.
I have a 1974 C10 350/350. I have a vibration between 40-50 mph that goes away after 52ish, i also notice at around 67-70 vibration comes back but its a longer and nowhere near vibration/more like road feedback. Its in the seat and as i maintain speed or accelerate. its a pulsating/rotational vibration, as i climb from 40 on to 50 vibration increases in sound and vibration strength with speed increase. Ive tried to replicate the vibration under same rpm range with negative results. Another thing, after i got my drive shaft re-balanced the vibration at 67-70 has now become more apparent and seems like it got worse while 40-50 remained the same.
I can power through the vibration. 40-50 but not high 60 since my powerband is gone by then
I have purchased new tires, U-Joints, replaced bent rims, new tires and balanced the drive shaft.
What else am i missing.
Thanks
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How is your exhaust mounted? Trans and engine mounts are good? one or two piece driveshaft?
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Buddy had a jeep that had broken tranny mount. We could feel vibrations at certain speed intervals.
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How is your exhaust mounted? Trans and engine mounts are good? one or two piece driveshaft?
Exhaust is true dual with hangers, away from everything and free.
One piece drive shaft
Mounts are good, got inspected today
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Does it do it under decel? What happens if you put it in neutral? Have you checked the rear end?
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Does it do it under decel? What happens if you put it in neutral? Have you checked the rear end?
Only under acceleration and maintaining speed withing the range. I'm not sure what to check in the rear end.
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Remove the cover and inspect for metal fragments, broken or damaged gears, etc. Check bearings, side clearance and backlash. Then do a gear tooth contact pattern analysis
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Years ago I had a similar vibration / it was a harmonic vibration in my 55. One day I went out to get in it, there is a puddle of gear oil under it. They are similar to a Ford 9", a third member style. I look, and there is a big crack in the third member. Vibration was gone after that.
Could be a bad bearing in the rear end.
Could be someone replaced parts in the rear end, and didn't set it up correctly.
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Remove the cover and inspect for metal fragments, broken or damaged gears, etc. Check bearings, side clearance and backlash. Then do a gear tooth contact pattern analysis
I recently replaced differential fluid, gasket and cleaned the cover. I didnt see fragments or anything that looked damaged. I havent check rear bearings yet. Are those hard to replace? I replaced my front ones with new rotors.
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Is it possible my rear bearings would cause this vibrations? I also noticed when i decelerate it now vibrates as opposed to before the driveshaft fix
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You need to determine if it's speed related or RPM related. Does it do it in second gear the same as third gear?
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You need to determine if it's speed related or RPM related. Does it do it in second gear the same as third gear?
no it's only during that speed range. I've gotten the rpm ins 1st and 2nd as the same as thurs with no difference.
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huh?
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Out of balance drums?
Bent rear axle?
Loose torque converter?
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huh?
Sorry stupid phone. It does it regardless of rpm. It is only in that speed range.
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Let's be clear, under cruise or acceleration in 2nd or 3rd gear you have vibration that appears between 45-50 mph and reappears at around 70 mph. In neutral or under decel it goes away. Your tires are not the issue, no bad wheel bearings, driveshaft is good. So if this is accurate I'd be checking that rear end.
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I had the worst toughest vibration in all GM history. However, it only vibrated on accel and in park,,thus, bad engine (crank). It was easy for me to diagnose. LOL!!!! Just kidding, 4 mechanics couldnt figure it out before Vile did. Therefore, i'd be checking that rear end. Rumor has it, Vile knows a thing or two about these old chevy trucks.