Pulsing vibration

Ok so I posted a problem a little while back when I got my truetrac installed. Ever since having my truetrac installed, I get a pulsing vibration from 40 to about 60mph. Took it right back, and they flipped my driveshaft, and greased the u-joints. No vibes for 1 day, then they came back, just not as bad, it's actually sort of faint, but still there. I can feel the vibes in the seat, floorboard, and steering wheel. The pulse isn't in the gas pedal, but the pedal does seem to vibrate. Now in this time, I've had the front end checked and aligned, tires balanced at another shop, and the center bearing and u-joints checked by the shop that installed installed my truetrac. He says they are all fine, a little slack in the rubber of the center bearing, but nothing bad, an told me that there is nothing more he can do, as he is a transmission shop, not a driveshaft expert. I'm running out of ideas, and I'm taking a long trip Saturday. Help?

 

Bump

 

Bump

 

Have you checked center driveshaft support bearing? Might have play? Watched video of guy shaking by hand showing excessive play. Truck was on lift but maybe you could slide under and see. GL

 

There's some slack in the rubber of that bearing, trans shop said he wouldn't worry about it

 

My guess is its in your diff. My brother put a auto locker in his and after install he had some vibration and had a diff shop go through it. I think his had to be re shimmed. might take it to a diff shop.

Tim

 

I brought it back to the shop I had it installed at. They said it had to be driveshaft related. Couldn't be in the diff

 

For an update, he basically called you a dumbass who doesn't know what he's talkin about. Even though you're not the only one that told me shimming could be wrong. There is play in the center bearing, I think I'm gonna order a new one. Also, I got under my truck last night after a big trip, and I have diff oil everywhere under the passenger side if my bed. Looks like they screwed up my axle seal as well. It's dripping down my brake drum

 

That blows man.Hope that shop acts right for you.

 

Did the Dumbass shop install new axle brgs and seals?. lol.

 

No. The dumbass never even mentioned it, and me never being in a diff, I didn't know he should have till now. Lots of people have told me you always replace the seals when goin into a diff. I told the guy to get whatever parts are needed, and he never mentioned the axle seal. He did install new carrier bearings and races.

 

I'm trying to keep my cool. I don't wanna spend money on driveshaft work, when there wasn't a problem before he installed my Truetrac. Then I found the leak. There's only 4000 miles on this diff since they worked on it, and idk how long it's been leaking. As soon as I found it I drove down and literally blew up on the owner, and he sounded at first like he was gonna screw me on the leak cause it's been so many miles, but today I went so they could make sure my fluid was ok, and it wasn't even a pint low. So he topped it off and said come in next week, they'll pull the axle and fix the leak. He'll also throw in a new center bearing for a minimal charge if I want