Driveline Vibration

[bstef]

Have 87 excab with 91 305 TBI engine. Used motormounts from website. Used stock rear crossmember. Can"t get rid of small driveline vibration.. Tried about everything. Raised tailshaft mount raised hanger bearing mount. Changed pinion angle up and down. Next step I guess is to stringline the drivetrain But I didn't think I should have to since I used correct mounts and stock crossmember. Oh Well Any Suggestions. Thanks. Bernie Steffen http://www.s10v8.com/images/smilies/icon_confused.gif By the way Balanced the driveshaft.

[spacecadet]

Does the flywheel have a weight on it that it shouldn't?



Are all the torque converter bolts the same? Even the use of one odd lenght bolt can create a vibration.



Pressure plate OK? I had one that lost a finger. It vibrated for the longest time. At least until it smoked the motor.

[BrandOmatic]

boy, if a driveline vibration in my truck wasn't a saga of b.s. strung over about a 3 year period, i don't know what is.

mine is a one piece shaft, regular cab truck however. but the ending fix finally, was simply a re-balance of my 2nd new driveshaft. the guy who did it told me he would spin his machine as fast as it would go and balance the shaft within a very tight tolerance. since then it's been smooth! i tried re-balancing wheels, different stock balanced wheels/tires, pinion angle changes, modified the trans crossmember.. etc. it came down to the driveshaft not being balanced enough for the speeds i apparently was turning it. 3.73 gears, 26" tire, 80mph or so. not that fast but fast enough to cause a problem.

[bstef]

Flywheel, or flex plate, is the one that was on the engine is the caprice. I put all new bolts in the converter. This is not a high speed vibration. seems like it is worse at 35 to 60 mph. thanks for comebacks. Bernie Steffen http://www.s10v8.com/images/smilies/icon_frown.gif

[Melonhead]

Bernie, check your u-joints. The joints need to be centered and have the limiter clips installed. The few problems I have seen in the past are no c-clips on the ends and the joint slid to one side. The other is too small in width of a joint and would slide back and forth.



The best advise is double check you drive shaft. Next thing to check is pinion angle if nothing else works. Get an angle finder from hardware store and measure the angle on each bend. The front yoke to the shaft. The shaft to the pinion yoke. The total angle from both should be less than 6 degrees.

[bstef]

Melonhead Driveshaft was built by reputable driveshaft shop, However I will check these things out. I had it built after I got the truck running and had the vibration. I have a angle finder and I can check the angless. ?Thanks. Bernie http://www.s10v8.com/images/smilies/icon_wink.gif

[riotpolice75]

driveline vibrations SUCK. i ran into 2 of em right after i got my blazer back on the road. the first one was me forgetting to put the pilot bushing in for the input shaft. i did that. the second one was a major vibration from 30 on up.



take the driveshaft off of the truck, put a drain pan under the tailshaft to catch anything that might come out, put it in drive and run it up to 60 or wherever you run it up to where the vibration stops. thatll at lest let you know if the vibration is in the engine/trans.







smith

[BrandOmatic]

i'd have to say check that the tires are balanced good then?? my neon used to shake through the steering wheel at about 70, but would smooth out beyond that and at about 55 and below. rear wheel drive would probably shake through the truck or drivetrain.

[Scotty_S-15]

Another source for vibration that I don't think was mentioned.............. (Although not common)



If the driveshaft is a little too short, causing too much of the yoke is sticking out of the trans, and the trans bushing is a little sloppy like most are, the nose of the driveshaft can get to whipping around. That ain't good.

[oncearacer52]

Trans mount rubber pulled loose maybe? Looks fine but at speed it will wobble if bad. A stock one only lasted one day on my truck. Ruined my trans case.

[bstef]

Thanks everybody for the ideas. I will check everything out. I found out today my trans is leaking from the front seal. I have to drop the tranny anyway so I guess I'll start from scratch. I already have a new torque converter for it and I wanted to install it. So here goes. Damn those top bolts anyway. Later and thanks again. Bernie Steffen http://www.s10v8.com/images/smilies/icon_eek.gif

[s10carguy]

could be lousy tires that are out of round or maybe screwed up belts. you got radials all around?



I get those top bolts with a long extension. remove the crossmember and lower the tranny first?