Rear tray for my rusty '86 pickup (1 Viewer)

[mongoose2231]

No need to read it all. It has new ome springs and bushings in the back. The noise did not appear immediately after the lift in the back. It kind of gradually came to be. Perhaps after the lift in the front It got worse. But not sure how they correlate. I'd have to get shims to change the pinion angle. Do t want to be cutting and welding anything yet.ill remove rear shaft and drive without to see.

 

[mongoose2231]

Removed driveshaft, drove in fwd and it no longer makes any vibration. I need to speak to Tom Woods to see if I can get one of their custom dc shafts. Pfft, I wonder why the vibration didn't show itself right after the new lift and it only showed now, two years later.

 

[knuckle47]

Wear and tear?

 

[mongoose2231]

Spoke to Tom Woods, they said to try balancing the shaft before I buy a dc shaft.
Imma try doing that first.

 

[mongoose2231]

Ok, so 3 months later, I found the issue. I must admit, I haven't really tried to diagnose the problem any more. Got everything renewed in the driveline, so that is a plus. Should last a good 20 years more.
Now, onto the exciting part. The problem was the transmission mount. I can't believe I didn't bother to check that. I was under there a million times, never paid attention to it until my brother had a simillar issue with his lj70 cruiser. Apparently has the same tranny tcase combo. His tranny tcase mount was shot. Truck was undriveable. I was sitting at my desk this am and I said to myself: " let me check the mount and see it its broken".
Found one rubber leg missing and the other dislodged and just sitting sandwiched between the two pieces of steel. I ordered one, will replace as soon as it comes in and report after. Moral of the story is to start with the simplest thing when diagnosing. Could have saved myself the trouble of doing all of the work I did to try and rectify the problem. Funny thing is that I know of the " start with the simple thing first" slogan but I completly failed this time around.

 

[aztoyman]

Glad you found it. Thanks for updating the thread.

 

[mongoose2231]

Yes, I am going to post some pics once I take it apart. Just waiting on the parts to get here.

 

[ferg]

What mount did you buy? Not a stock one I hope.

 

[mongoose2231]

I bought an aftermarket mount from parts geek. 'Twas 38 bucks.
This.

 

[mongoose2231]

Done, here is what the old one was like under there.

 

[mongoose2231]

There were no rubbers and it was fully collapsed. Got the new one in, vibration is gone.
Now, to remove the lift off of the front. Going back to stock. The steering is so twitchy now, at speed, the slightest movement of the wheel feels like major input. She's been aligned, New control arm bushings and cam bolts as well. All new steering components too. Caster must be out of whack, as it drove beautifully before lifting.

 

[knuckle47]

4 degrees of + caster changed my Saginaw steering conversion on the FJ40 from a squirrelly ultra light over steering mess to a perfect 1 handed stable steering wheel. You’re probably correct in just the assumption. After a computerized re-check of the caster setting it read +3*. @Jdc1 had to explain to the tech how that was perfect in this application

 

[mongoose2231]

My truck is ifs, and without changing the ucas, there will be nothing I can do to rectify. And the ucas can't be replaced because the torsion bar suspension.

 

[ttrmike]

I think the OME torsion bars ride better than the stock bars when set at OE height. Certainly a lot less work than swapping it all out. I set front ride height to 12.25in from the ground to the center of each front camber bolt for 31in tires.