allright heres the deal., i bought a used rearend with a 373 gear and put it in today., i had the cover off and it looked fine inside., filled it and installed it today., i whent from a 273 to the 373., very happy with the pulling power., feels perfect untill im well into the rmps in the higher gears., 1st- 6000,,2nd 6000, 3rd 5500, at 5500 in 3rd it starts, as soon as i shift into 4th under full power its shaking, and same into 5th., really jaring feeling in the shifter., you feel nothing anywhere else or hear anything.,if i drive it normal it feels fine.,very smooth, ive drivin it a few times across gandy today., i have no idea how fast im going with the new gears., i feel nothing in between the gears.,i looked at the ujoint and it looked fine, i havent had the car long at all and really have pushed it up on top end., between being a covertable,welds and old brakes ive really never pushed it up high., i had a old factory clutch in up untill a couple of weeks ago and it was slipping up high when stressed.,so i really hadnt pushed it other that down low......what do you guys think?

 

Try disconnecting your driveshaft and spinning it 180. Sometimes this can help.

 

Sounds like the driveshaft vibrating, ... might be time for an aluminum driveshaft

I saw you on gandy today by the 7-11. I was selling more wheels

I heard tires squeelin, I turned around, and I saw a green vert on welds

 

hmmmm had a vibration problem in my 69 stang. turned out to be the universal joint..... Id say go the aluminum route.... only 150 bucks.

 

yeah that was me, i didnt see you., the new gears feel great down 123rd, ive got alot done since you saw it last, i guess i might as well look for a aluminum driveshaft now, one damn thing after another!, i have not closed my tool box since the day i bought the damn thing!, its fun but costly, ill be working on the nitrous tomorrow., i just hope its the drive shaft or ujoint., i dont want to have to jank the rear again., its no fun on the ground!

 

i had the same problem with my stang when i first got it, it turned out to be the actual bolts in the drive shaft u-joints were loose and backing off little by little. so i just got me a aluminum and havent had a problem since.