Diagnosing a bad converter

[Lit549]

Just curious of the best way to narrow down a vibration I have..It vibrates when I let off the gas, I've separated converter from engine and it seemed better.Trucks been lowered, I set all angles equal but opposite and shafts has been balanced..The vibration seemed to get worse when I added an h-pipe in the dual exhaust with 40 series flowmasters..Drove it for awhile and it had a constant oscillating vibration at 50-55mph, then I cut the two east hangers closet to the cab so just the rear hangers are holding exhaust up; the vibration got better.Now it only does it when I let off the gas..I just wanna make sure the converter is good, I'd hate to make my engine rear seal leak or worse..Its a rebuilt 350c and converter was whatever trans shop put in (factory stall)..I'm not sure where they get the converters but I don't trust it (cheapy)..I've chased that vibration forever, but I'm sure I had it from several different places through the build and sometimes made it better but still have this slight vibration..I is dropped4-6 and done r8ght, new tires ..Everything but rear gear has been rebuilt, any suggestions??

[bd]

Here are some possibilities to consider and get you started.  Do you feel it, hear it, or both?  Does it require that the vehicle is moving or will it do it standing still?  Have you verified the exhaust isn't hitting anything - that there is ample clearance along the full length of the exhaust?  Are you sure you don't have a cylinder misfiring?  Have you verified that the motor mounts and transmission mounts are tight?  How about the transmission bellhousing bolts?  When you slipped the converter back, did you rotate the flexplate and inspect for cracks?  Have you checked that the transmission and pinion yokes are tight?

[Lit549]

've cheked everyth8ng, I can only feel it..When I let off gas ..All mounts are new and tight, flywheel is new and uncracked, and it only does it at speed..That's why I'm thinking converter cause it has done it (used to be worse) every since I got the truck..Like I say, I think I've fixed several issues causing vibrations but this is the best it's been..Drives me crazy! I'VA rebuilt trans, rebuilt driveshaft, new bearings, rotors, axles, rotors, drums, plug wires, distributor, NEW ENG8NE, mounts, exhaust,,,, lol..I'm about broke and:::still vibrates!

[pholliday1]

Gotta a Go Pro? You really need to see what going on with your pinion angle as you accelerate, more specifically because its fine when not in motion, it would be interesting to see how much movement you are getting when your on and off the throttle. Its the "oscillating' word you used that has me curious.

[Lit549]

http://youtu.be/wPqG1oY5SII
Well it just feels like it's the converter, it vibrates but seems to get better when it warms up..Here's a video of me pushing on the converter to show how it rocks on the pump shaft..Arm they supposed to be that loose ? I've never noticed a converter with that much slack to it..

[Irish_Alley]

lit im gong to say this because i cant watch the vid right now. but even new parts can be bad right out of the box.

[Lit549]

Well, I've checked everything! Pinion angle is correct, exhaust isn't touching anywhere, engine isn't missing, tiresare allbgood, no bent wheels, new axles, bearings, rotors, drums, and it still has the oscillating vibration that's speed sensitive. It does it mainly at around 40-45 when I' light on the throttle...I can feel it through the floor and steering wheel..Its a shame to cause I love the truck, the vibration ruins it though..

[Captkaos]

In the video you did find a problem.  Based on it your torque converter isn't fully bolted to the flywheel.  It shouldn't be moving between the flywheel and converter at all...

[Lit549]

In the video you did find a problem.  Based on it your torque converter isn't fully bolted to the flywheel.  It shouldn't be moving between the flywheel and converter at all...

Yes, it was unbolted; I was showing how much rock it has to it..But I guess when it's bolted up that "play" doesn't matter?? I don't know if that much play is normal or not, or if it even matters?? I also watched exhaust with engine running and it sure moves alot..I'm wondering also if the exhaust is in a bind and causing the vibration? How many hangers do you guys run? And where?

[Captkaos]

The exhaust technically won't cause a vibration unless it is hard bound to something.