Shuttering 351
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Shuttering 351
Got an 87 Bronco with a rebuilt 351 and auto trans. Motor has under 1,000 miles on it. Over the last 100 miles or so, a strong vibration has developed through the steering wheel (actually shutters quite bad and you can feel it thru out the vehicle) while accelarating. The vibration begins around 1,500rpms and starts to smooth out at around 2,100rpms (40mph or so) and is present under both acceleration and drive conditions). The vibration, however, immediately disppears under coast conditions. The truck runs fine at higher speeds and idles smoothly. Any thoughts on the subject? (at first thought of wheel balance but wouldn't that be constant under accel, drive, and coast?) Thanks in advance.
Skippy
Skippy
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From: Durham
Shuttering 351
It very well could be wheel balance. A lot of times an out of balance wheel will vibrate at only certain speeds. It also could be a bad shock. Being as the engine was freshly rebuilt, does it have the correctly balanced flexplate? Or is it loose? Maybe the torque convertor is causing the vibration.
'82 F150 2WD w/351W (orig 300 I6)
Slik
'82 F150 2WD w/351W (orig 300 I6)
Slik
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Shuttering 351
Checked u-joints last week while going over the underside and found no play in them. As far as the flexplate goes...uhmm...whats a flexplate? If you mean harmonic balancer its new-replaced at 1st rebuild last year; if you mean the flywheel (or its equivalent)-its original. How could the torque converter cause this? (you can see I have a limited experience with automatics) Thanks for your help.
-Skippy
-Skippy
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Shuttering 351
Had the truck checked out for the vibration this afternoon. Flexplate was nice and tight against torque converter, no cracks, no play evident against crank (didn't pull tranny), u-joints are tight. But did find broken tranny mount with all kinds of up/down-side/side movement. And of course, Ford discontinued the 87 style tranny mount mid-year 87 (mine is early 87) and this particular mount is dealer only. $144 and I can own it but I was thinking that maybe I can swap an 86 or earlier or late 87 and newer junkyard crossmember w/ mount. Anyone know if they'd bolt up to my C6 tranny?
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From: Durham
Shuttering 351
A lot of torque converters will give a shudder before they completely go out. Sometimes changing the fluid helps for a while.
I have my old tranny mount from my '82 with C6 if you want, but I didn't have any trouble getting my new mount from Ford (2 years ago, now). You should easily be able to pick a good one up at the local junk yard.
'82 F150 2WD w/351W (orig 300 I6)
Slik
I have my old tranny mount from my '82 with C6 if you want, but I didn't have any trouble getting my new mount from Ford (2 years ago, now). You should easily be able to pick a good one up at the local junk yard.
'82 F150 2WD w/351W (orig 300 I6)
Slik
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Shuttering 351
Replacing the tranny mount didn't change much. But the shuttering has gotten worse since last post and it developed a "different" sounding clunk. A transmission place up the road told me to pull the plate off the rear diff and inspect. Sure enough, carrier pin is all kinds of loose in the carrier and all four spider gears are loose and worn to a point. So I guess I'll either replace the carrier and spider gears with new ones or find a used axle.
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Shuttering 351
Well, how does one eat crow on the net? I said the u-joints were tight, flex-plate was checked, etc, etc. When, as a last resort, and convinced my recent transfer case went bad (on the advice of a tranny shop up the road), I raised the rear axle Tuesday night and tried to find play (one last time) in the cv joint (on driveshaft) out of the T-case. Found a little bit of play but not much. Decided to have them changed anyway....and the vibration is gone. Instead of jumping the gun and believing the first bit of advice (from the tranny shop), it would have saved me alot of extended self-imposed grief to have stuck it out and followed the "path of least resistance" aka troubleshooting. This is a secondary rebuild truck project and maybe I shouldn't get so jumpy. Thanks for the replies.
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