Long story short, purchased a limited slip off a site. (we know which one that looks like a garage sale). "Low mileage unit, Excellent condition".


Bought it, and paid an unbelievable price to have it trucked from TN. When it arrived the shipping was 1200 vs the 204 the seller told me it would be, my mistake for not calling the freight company.


I needed it as my old unit was south, so I just ate the southern hospitality as the axle did look very good. Pulled the old, put in the new. Drained and filled it with correct unit lube and addy. Didn't rally perform well locking up from the get go.


Was on a 500 mile trip to drop off the kids piano and on the way home.....
Low rumble, 40 miles later vibes. Got home and checked lube level and did the dog pissed on inside of tire check. Nothing.


Dropped a back of hand on both rears and the dif. Normal temp.


Slept on it. Next day on the way to work, 20mph to 40 it's like a puppy ****ting razor blades.


I now have two sterlings with a heavy bill.


Question I ask is do I take the axles to a shop and have a tru trac put in with the parts from both axles (I need posi in Michigan winters).


My original "open" rear just had a bad yoke. Unknown about the ******* I bought?


My orig had 209k.


Just want to do this one more time and get it right. I only have one horse and I ride the **** out of it.


Thanx for your time and steering!!


Denny

 

go to a pro and let them straighten it out once and for all

 

I had a Detroit locker I sold awhile back on CL $200 and I'm in SE Michigan. If you want I can ask around depending on where you're at in MI I may be able to help you out. I would advise a locker since your Ford is way to heavy to be pushed around by any locker.
I'm sure you know but just to be sure your truck came with a 10.5

 

I would have a powertrain shop do both diff's and then keep the best one, and sell the other to recoup some of your loss. Should sell easy with rebuild papers and warranty.

Just a thought!

 

I'm sorry you're going through these woes - many of us know what an expensive setback feels like. I didn't mess around when my pinion bearing was spun, I took it to the pros and had my rear end upgraded for long life with bigger injectors and planned heavy towing.

In your case, you have your old unit that you know how it was treated and apparently you know what's wrong with it. That one is the best candidate for repair by the pros. I realize that swapping rears twice is akin to the frustration of stacking bowling ***** in a pyramid - but the frustration level has the potential to be greater with "new" rear end. The truck is squawking about having a mysterious foreign object shoved up its butt - you might want to undo that.

 

I had a Detroit locker ("made in Taiwan" stamped right on the side of it, SMH) put in about 4 years ago. Towed a 9kTT many many times, horses in a 3 horse slant, plow heavy with a ton of salt in the bed. Never had any issues with it...knock on wood. It's the one modification I have never had any problems with.

 

Tug, I've never heard of this mod for a differential!

(sorry, you're the wordsmith)

 

It's not a mod - it's undoing 14 years of wear and two years of axle-wrap with big sticks. The "upgrades" are ladder bars for a stock-height truck (this was a huge help, even when hyper-mileing) and one of those finned pumpkin covers with a larger capacity (no discernible change with an IR gun). I now think those fancy covers are nothing more than bling.

 

1200 dollars for freight.. that ridiculous for sure.. the rear end can not weight that much.. that more than a new rear end would cost..

sorry about that man.. always remember what Reagan said.,., "Trust but Verify"

I tend not to buy stuff i can not pick up in person or at least on ebay where you have some protection. Hope it all works out.

 

Thanx for the replies and advice.


Here's the update.


Took it into two different shops. First shop said they couldn't find a problem and could not isolate the vibration. Said they would have to do a major tear down of the drivetrain to examine the problem.


I begged off and took her home and began a reexamination (again) myself.


Took off front "Milemarker premium hubs" ran it out. still shook.
Took off front drive shaft ran it out, still shook.
Took off rear driveshaft and installed the front shaft and hubs. Locked in the 4x4 and ran it out. Smooth as silk.
Grabbed my repair records and noted that all 7 u-joints were replaced 6 months ago.


The joints were the lubeable top of the line.
After a couple of hours letting things digest, I nailed it down to the driveshaft as the cause.


Checked for the trueness and balance and it all was good.


I then began the intensive study of the ujoints. Being new and still having red grease on all the zerks as well as feeling tight in the wiggle, wobble, rotation test. I was at a loss.


I decided to take the "See a snake kill it" approach and removed all the ujoints for inspection.


What I found was the extreme rear joint had dry caps and one cross was completely bearing free and fused.


This puzzled me as I am very proactive with a grease gun on a normal basis to avert this kind of failure.


On the bench I placed the U joint in the vise and applied the grease gun. To my amazement the fitting wouldn't accept grease. Keep in mind, this joint was virtually new. I pulled the zerk off the ujoint and installed it in the gun and it still would not flow grease.


Replaced the joint and carefully observed grease flow thru the joints as I lubed them. Reinstalled the shaft and ran it out. Drives like a new truck.


My lesson, just because it's new. Don't take for granted that will perform as new and be surgically centered on the smallest detail. In this case it was a faulty zerk that caused all my pain. I will not use an air powered grease gun for any purpose again.
I want to see and feel the actual movement of the lube going thru.


Who would of thunk???


Just wanted to update those who replied and let the forum know that even if you think you ruled out a factor and move forward. It might be worth while to retrace the steps you took for maintenance just ahead of the problem your having to see if your proactivity caused your demise.


Thanx for the read!!!


Denny

 

No such animal. A u-joint CANNOT be "top of the line" and be lubed externally at the same time.


That will do it.

Over-greasing is often worse than under-greasing.

I don't use one either and I grease a lot of equipment. I however don't use one because of extreme pressures that ruin seals on a regular basis. The same goes for those electric ones. Forearm power only.

Me.

 

This obscure crap can drive a person crazy - like it has with me. I talked to the experts and they told me the U-joints with zirks are a good concept, but they don't have the same longevity in reality.

 

I was always told the greasable ones were weaker due to the passage ways for the grease for like performance applications.& also was told that the greaseable ones would out last the sealed ones.the sealed ones on our truck made it to 210k,some were good shape & some were poor shape.I went back to the sealed ones beings were pavement pounders now, no forgeing rivers anymore.

 

Don't beat yourself up.

I think most people here have an experience as yours. Maybe not as expensive, or possibly more.

How many people have bought 8 Injectors when just O-Rings were necessary? Or, a Turbo when it needed Rings - Saw that a while back.

Nonetheless, Wisdom comes with Experience. Both of them come at a financial cost. This time it was $1,200 Shipping.

On another note, if you Tow a lot, or live where hills are the predominate roadways; You might consider getting the other set up with a Taller Set of Gears and do a swap in a few months.

 

Glad you solved your problem! When I had my driveshaft balanced I asked the driveline shop which lasted longer. They told me the sealed u-joints almost always outperform the greaseable ones. I always thought the opposite.