Rear end vibration....pinion bearing?

Topic: Rear end vibration....pinion bearing? (Read 11216 times) previous topic - next topic

Rear end vibration....pinion bearing?

Reply #15 – July 22, 2009, 12:54:37 AM

Quote from: CougarSE;283121

Well it looks like your driveshaft is spinning at 3300 rpm to move your car at 70mph.

thank you.

so when are you going to jack up the one rear wheel, get under there with the the car in N, grasp the yoke and twist / lift up and down.

you had the tail shaft bushing replaced,,yeah i know. now lets see if they really did it or not.

the best way is to drop the d/s from the rear and then do the above.

the last think i can think of is your d/s is out of phase due to the ujoint work.

or...get a second opinoin on the rear end.

Rear end vibration....pinion bearing?

Reply #16 – July 22, 2009, 02:06:02 AM

I *think* I may have sticking rear drums. Here's why: I had the car up on jack stands with the rear wheels off and ran it up to 70 mph with the rear wheels off and the drums bolted on. Sure as shiznit it vibrated. So I stopped the car, put in in neutral, and shut it off. I went to spin the drive shaft and I could only rotate it so the rear wheels would move forward.I tried to spin the drums and they would only turn forward, not in reverse. I couldn't turn the wheels in reverse. So I put the car in park, turned it back on and ran the car in reverse. I then shut it off and put in in neutral. I went to spin the wheels by hand and now they went forward and reverse. Another thing I noticed this weekend when I had it out was it vibated like usual on the highway but after some stop and go road construction (ie hitting the brakes a lot) it stopped vibrating when I got to 70 after the construction zone. So when I get time this week I'm going to be pulling the drums apart to check for sticking.They might just need to be adjusted (hopefully :hick:)

Rear end vibration....pinion bearing?

Reply #17 – July 22, 2009, 09:06:28 AM

now that sounds more like it.
if they are adjusted out too far, you should have trouble getting the drums off.

Rear end vibration....pinion bearing?

Reply #18 – July 22, 2009, 05:42:40 PM

So I took the drums off today and it's not the problem. Everything checks out fine. So now we're back to the drive shaft/drive line/rear end. I'm going back to the shop that balanced the shaft Tuesday and he's going to pull it and recheck it along with checking everything else in the drive line. I'm going to stay in the shop so I can see what ever he finds. It should be a fun day :hick:

Rear end vibration....pinion bearing?

Reply #19 – July 22, 2009, 09:57:09 PM

You know the more I think about it the problem has to be the drive shaft. If anything else in the rear was vibrating it would happen well below 68-70 mph. Since it starts at 68-70 mph, in 3rd or 4th gear, it has to be the drive shaft.

Rear end vibration....pinion bearing?

Reply #20 – July 23, 2009, 07:03:55 AM

Post the findings,I still have the exact same issue.

Rear end vibration....pinion bearing?

Reply #21 – July 23, 2009, 11:22:44 PM

Well I changed the transmission mount just for fun today and even though it was broke the vibration didn't change. At least I fixed the broken mount :hick:

I'm wondering if this vibration has something to do with the design of the drive shaft. I've noticed that a lot of Fox Mustang guys have this same problem going to higher (3.55 or greater) gear sets. It could be that the higher gears cause the drive shaft to reach it's critical speed. This seems to be solved among Mustang guys with an aluminium drive shaft. I'm thinking if the drive shaft shop can't get it to balance I might get an aluminium drive shaft from a Police Interceptor and have it shortened to fit my T-bird.

Rear end vibration....pinion bearing?

Reply #22 – July 24, 2009, 12:35:16 AM

or an aerostar d/s

can you pull the yoke out of the tail end and post a pic?

did you check play in the axles when the drums were taken off?

not sure about your 3.55 theory as the problems should be pretty common with folks running 3.73 as well.

Rear end vibration....pinion bearing?

Reply #23 – July 24, 2009, 11:46:09 AM

Quote from: jcassity;283532

or an aerostar d/s

can you pull the yoke out of the tail end and post a pic?

did you check play in the axles when the drums were taken off?

not sure about your 3.55 theory as the problems should be pretty common with folks running 3.73 as well.

Axles are tight so that's not it. Yoke looks ok as I don't see any damage to it. I'd have to pull the shaft out again to get a pic but I won't have time to do it this weekend as I'm busy.

I'd do an Aerostar drive shaft but every one at the yard is bent:hick: The Police Interceptor shafts seem to all be fine though.

As for my theory: I've read a bunch of threads on Mustang boards about guys with Fox bodies switching to 3.55 or higher (3.73 & 4.10 included) gears having problems with drive shaft vibrations with the stock shaft. Since I have 3.73s and the stock shaft I'm thinking that it *may* be my problem. The common cure among Mustang guys is a FMS aluminium shaft. Since that wouldn't work for a T-bird I figure my best bet would be a cut down Police Interceptor drive shaft. I'll wait till Tuesday when I go back to the drive shaft shop. It should be a fun day;)

Rear end vibration....pinion bearing?

Reply #24 – July 24, 2009, 04:06:44 PM

When you had it jacked up did you try running it without the drums? just something to throw out there. did you try the hose clamp trick? you just about covered everything else.

Rear end vibration....pinion bearing?

Reply #25 – July 24, 2009, 04:44:06 PM

Quote from: Kitz Kat;283632

When you had it jacked up did you try running it without the drums? just something to throw out there. did you try the hose clamp trick? you just about covered everything else.

I haven't tried either of those. I should have tried the drums off when I had the wheels off the car:hick: Oh well. I really don't have time to mess with it this weekend so I'll have to wait till Tuesday. Like I said I'm staying at the shop on Tuesday till this is fixed.

Rear end vibration....pinion bearing?

Reply #26 – July 24, 2009, 04:54:46 PM

I don't think it's the drums.I'm REALLY leaning towards the driveshaft.I think I'm going to just run to the yard and grab a cop car driveshaft,but,I'll have one problem,NO-ONE around here will touch an aluminum driveshaft.If that doesn't pan out,I may just have mine re-balanced.

Rear end vibration....pinion bearing?

Reply #27 – July 24, 2009, 04:59:23 PM

The guy who "balanced" my drive shaft can make an aluminium one so I'm pretty sure he can cut down a cop car one to make it fit.

Just wondering but does anyone know if the 4R70W and AOD input yokes are the same? If so can I re-use the one from the cop drive shaft with new u-joints if I go that route? I figure the axle is the same as the 8.8 and 7.5 use the same axle

Rear end vibration....pinion bearing?

Reply #28 – July 24, 2009, 05:04:43 PM

Good questions.I'll have to look around for someone to weld mine up.

Rear end vibration....pinion bearing?

Reply #29 – July 24, 2009, 05:12:25 PM

I think I'm going to go to the wreaking yard Monday and grab a Police Interceptor drive shaft. I think I'll bring it with me for shiznits and giggles if the stock shaft won't balance out. I just wonder if I can fit it in the T-bird :hick: