~95 F-150 8.8 rear with auburn ECTED diff~



I blew the driveshaft in my truck doing a burnout a few weeks ago...


...I limped it home in 4wd and got a new balanced shaft from end to end.


I recently re-built my rear end (about a month ago) as well.

Ever since I blew my driveshaft, I've had something wrong with the rear suspension.

The truck wheel hopped pretty bad when I blew the shaft, worse than it's ever done (probably why it broke) and that might have been due to loose axle u-bolts from the recent rear end job (pulled the whole rear end).

Ever since I got it back together with the new shaft, it wobbles/shakes/vibrates under power. I've 100% ruled out that I damaged the transfer case (switched it with another one) and noticed my rear end's u-bolts were loose so I tightened those up and realized that my pinion angle seems higher than it was. The rear has skyjacker 4" lift springs with stock 2" blocks and the little pinion angle shim under the spring pack.

At first, I thought maybe I spun the differential on the axle tubes, but I've previously welded the tubes and found no evidence of breakage there. I re-set the axle under the blocks and the springs and tightened the u-bolts to spec, and it still seems like the angle is high. I looked at the axle from end to end and did not see any obvious evidence of something twisted. I don't know for sure if it was as high as it is in the first place, but the pinion is pointed up in respect to the driveshaft and not down...isn't it suppose to be down? Or is it suppose to be up?

I did notice that there is a small gap at the back of the blocks though, and a light crack in the fresh paint where the perches are but nothing that sticks out as being an obvious explanation for a problem.

The rear end vibrates and shakes under power, i can hear a clunk when I get on it or play with it at low speeds, and the speedo needle moves around a bit. The needle obviously points to an issue with the rear.

I had taken the cover off the rear end thinking something was wrong inside but I didn't see anything obvious.


This one has me stumped....any ideas for me to look at?

How can I check my pinion angle to see if it's right?

I guess if there isn't much else to check I'll have to check to see if I twisted an axle shaft, or if I tweaked the diff carrier, but ....again....I'm stumped....

If you dont know...with the truck sitting right there in front of you...how the fuck do we?

Whose to say u put in a good tcase? How bad is the vibration? Id just run it until something blows up, then you know what your problem was.

i had the same problem with my bronco last year. i did a burnout and blew my rear shaft. i had problems with it vibrating then i started going through u-joints every week. i put a new driveshaft in since the last u-joint fucked it up. and it kept blowing them out. so i took the shim out and never had another problem for the next 8 months or so until i sold it.

Did you check the leafsprings from the forward attachment points to the axle? With all that CRAZY POWER to break the tires loose doing your burnout, maybe you tweaked/bent one or both of the springs. Might explain why your pinion angle is up from the permanent axle wrap you put on the truck.

Whose to say u put in a good tcase? How bad is the vibration? Id just run it until something blows up, then you know what your problem was.


The transfer case I put in is a known good one that I have used in the past.

The vibration is pretty bad. It's sort of weird too in that inbetween shifts or in neutral it doesn't vibrate much. And since the speed needle bounces a little that indicates to me that the rear carrier is moving as a result....since I just built this rear end I don't want to blow it up or ruin the R&P.

I checked to see if I ripped the tranny mount but that wasn't it.

I'll check the things that have been mentioned.


But what seems odd to me is the u-joint angles. It's a 2 joint shaft with the slip yoke going into a BW1356. The front joint is at an angle where the other end of the driveshaft is lower....and if my memory is correct I believe the other u-joint is suppose to be at the opposite same angle in order for the driveline angles to be right....

I've gotta look into how those angles should be.


It might be that something moved...and now my pinion angle is off....which is causing the vibration and causing the speedo needle to move and that nothing is actually screwed up inside the axle. I'll have to look into it but was looking for suggestions as to what to look at that which I might not be considering...


...Thanks again.

Well, I know what is wrong with it now...


...The tubes are indented where the spring perches attach to it. That is why the pinion angle is so high.

I found blistered and twisted paint around the front edge of the perch and noticed how the tube was a little out of shape.


:mad:


Think it's a bad idea to cut those perches off and re-weld them on for a temporary fix?

Maybe try tweaking them back (reverse burnout) :flipoff2: then guessting them to the housing. Thats what I did on some doods mustang that kept rolling the perches from doing wheelies.