bad vibrations

[bdan]

I have a '76 GMC Jimmy w/ 400ci, th350 and np203- Have had a slight whirring sound when cold, when first putting it into D or R- sound goes away in ~1/4 mi. or so. Recently, I've developed a bad vibration and lack of power upon accelleration. Feels just like a bad u-joint but they've been replaced- everything in driveline seems tight(externally), fluid is full and trany is shifting OK. according to Chilton, whirring cold comes from bad torque converter. Could this alone cause vibes? beech to replace?
Thanks

 

[NITRO]

first off, fill out ur profile, that wayif someone is close by, they might b able to help you. it could b a torque converter, but that doesnt make sense that it would just go out. if it is, it isnt that big of a bitch to replace, just hafta unbolt the tranny and unbolt the x-case x-member. then slid it back a lil till u get it out. we really need some more details

NITRO