Long story. First time posting.
Any ideas appreciated!

I'll try and make this brief.
69 Nova small block....9" 5.29 rear end....powerglide....REID case......6.50s 1/8 mile.......
Since tranny and converter rebuild this spring. Vibration in high gear only between 6300 and 6400 RPMS. Not before 6300 or after 6400...ran it up to 7000 in first and second to confirm. I usually shift car at 6700 to 6800.......don't feel it in low gear. Can barely feel it if at all in burnout but it is hard to hold at that rpm consistently. I DIDN'T HAVE this issue BEFORE tranny rebuild and converter rebuild. Yoke I had when there was not a vibration was tore up upon removal of tranny and inspection and was told it not hardned ....Tranny guy said i needed a hardened one..... he purchased and put a hardened one in during rebuild (he had the whole car at the shop)........It vibrated like crazy first time out. When I attempted to remove it would not budge......assuming it was Too big OD...(come to find out Reid takes a smaller yoke)... Had to pound it out. He put what he said was a hardened yoke of correct diameter in it. 1.500 to 1.501"...... It still vibrated but MUCH less. I probably made too many passes like that and fi ally pulled it out. It was chewed up....i suspect it wasn't hardened. Bought the correct Mark Williams yoke 1.499" for the Reid case. I took it and had it balanced with the driveshaft at a driveshaft shop.... No change. Had rear wheels and tires balanced...no change. I removed the tail housing and installed a new roller bearing. I discovered he had put the incorrect height bearing in the tailhousing. It is supposed to be 1.25" the one in it was 1.0". I bought the right one from Reid. I took it back out and it is slightly less severe but still present at same rpm. The pull back on the yoke is about 1& 3/16". I am told that is too far. I am leaning towards getting a new shaft made and change out the universals just to eliminate another part.....i understand the pull back should be 3/4" to 1".......
Talked to Lane at PTC who recommended clocking the converter one hole on flex plate to see if that helps. I have checked pinion angle...looks like it is 2.5 to 3 degrees......check


That strange part is the harmonic at that small rpm band.....and not in low gear that I can feel.......and that it didn't do it before even with a chewed up yoke in it.........ANY THOUGHTS OR help is appreciated.

Been fighting a similar issue in my car. It vibrates in high gear @ 6400 rpm.

I have replaced everything I can think of at this point.

I need to update the following because I thought it was gone but it's still there.

https://drr.infopop.cc/eve/foru...667071186#1667071186

Thank you!! Sounds like a very similar issue. Some good suggestions in your attached thread......I am going to investigate some of those. Loosing the roller bearing doesn't sound like a terrible idea.....and pretty simple. Tired of fighting this.

I'm thinking of trying a stock tail housing next with a stock yoke if its still there.

I did have a planetary gear set out of balance once and it took out the tail shaft bushing.

I appreciate the feedback. I am hoping it is less $$$ but Marco also mentioned it could be output shaft....going to put a new driveshaft a little longer in it new universals ends....etc and clock the converter one hole. If that doesn't work it will be end of season and pull the tranny and converter out for a go through. Hopefully its something simple.....i appreciate the previous thread and everyone's input.

A little note: If you do decide to do a tear
down look into installing the ring gear stabilizer
supplied by Sonnax. Excellent add on.Takes the guess work about out of the equation on vibrations and noise in the planets.

https://www.sonnax.com/parts/3...-gear-stabilizer-kit

Part # 25810-S2 is for the 1.69 and the 1.80

A little video.

https://www.youtube.com/watch?v=opqkuNUop3M

Hope this helps. You can see just how much slop without this kit there is. A ton.
Going in mine on the next bench.

Thank you. That definitely seems like cheap insurance.

Mine was real similar. Drive shaft angle was off/pinion too low. Fixed, problem solved.

Thanks. Do you happen to remember from what ito what or how low was too low. Borderline like 0.5 - 1.0 degrees did the trick. Feedback appreciated.