I have been fighting a driveline vibration since I built the truck. I have had my driveshaft balanced and the driveshaft angles are dead on... The vibration is mostly above 100mph. Recently I discovered, when I grab the slip yoke at the trans, I can move it up and down about 0.050". I pulled the driveshaft and the trans output shaft can be moved up and down 0.100". Its bad. I bought the trans a couple years ago from a salvage yard and it was supposed to be recently rebuilt. It shifts and functions perfectly. The only problem is the tailshaft bearing is either loose or smoked. Can I easily replace that bearing, or do all the guts need to be pulled to get to that bearing? If so are special tools required to pull it apart?

 

You have to press the bushing out and press a new one in along with the rear seal, i am currently having the samn problem..... My bushing just bit the dirt on the way back from houston and had to call a tow truck..... Just tore it down today at the builders shop and we sent the brand new drive shaft back for a rebalance

 

Yeah...I thought it might just be as simple as the slip yoke bushing in the tailshaft... But tonight when I pulled the driveshaft out I pushed on the output shaft of the transmission and it is really loose. I presume this is supported by a bearing internally?
When you lost the bushing what happened? Why does the drive shaft need re-balancing?

 

The people who built it told us to send it back and they will check runout and everything on it, drive shaft was 1/2 to long, had vibrations above 75 mph, and waspushing the slip yoke into the back of the tranny when launching, which in turn put the bushing in a bind causing the bushing to rotate in the tailhousing, therefore tranny fluid couldnt get to the yoke to lube it, so it smoke the bushing, and beat the rear seal out lol

 

The output shaft will appear to be loose when the yoke isn't in. The spine slides in, and is supported by the outside of the yoke. Mine was loose too.

 

I see... Thats a bummer going home on the hook...
I'll call a few transmission shops tomorrow.
Any other input about my problem would be appreciated.

 

Did you have your driveshaft high speed balanced? I had mine balanced to 150mph just to be safe.

 

OK... if its normal for the output shaft to be loose without a slip yoke supporting it... is it normal for the slip yoke to move up and down with light pressure?

 

yes mine has more slack than yours id say almost 1/4"

 

I have the same thing on my 04 4l80e. It's normal.

I've had the same freaking vibration issue with my 2 piece stock driveshaft. I've had the shaft balanced, dents pulled out, and new u joints put it with no help. New carrier bearing too. I'm ready to say f*ck it and order a 1 piece Texas Driveshaft Specialists 4" shaft.