99 Ram QC 2WD 1500 5.9L just over 90k

I've had a full rebuild of my rear end at 80k in July of '06 by an ELT dealer I trust fairly well, and again at 84.5k by a local dealer in Mar of '07. Back to hearing the same symptoms in the last few weeks.

Starting at 40mph or so I hear a whirring/whining noise from the rear end only when the accelerator is down. Once you get over 55 the road/wind noise is louder. The previous two times the noise will continue to get worse until I got it in for the rebuild. Last time the dealer said the 'sleeve' was completely worn down and it was a horrible grinding noise, not sure what sleeve they are talking about.

I tow maybe once a year and it's rarely anything of any significant weight. When I originally purchased it I was told to use the 'Medium' use maintenance schedule, so I was not replacing the diff fluid every 15k. But I did have all fluids changed two weeks after the last trip, as I guess that's not part of a rear end rebuild.

I'm going to flip out if I get another $1200-1800 quote again, or even $800 in labor with parts under warranty. What else could they be missing to fix or replace that's causing this repeated failure after < 5k miles?

 

If its the same thing you could have a warped housing or something really wield. These rear ends are pretty reliable, and most people ahve 0 problems.

 

They are either using really cheap parts or not setting it up correctly.
Diffs can be very tricky to set up and most shops don't do it correctly unless they are a specialty diff and trans shop.
Most places willjust bang new bearing on the new gears and use the old shims. If the pattern looks "OK" then they let it go. It's quiet for the first while then it gets noisy from wearing improperly. A lot of places only check backlash and don't even run a pattern.

I think your the victim of a shabby workmanship. The tech probably thinks he's doing it right but he probably isn't properly trained or the shop doesn't have all the right tools. Probably both.

 

I believe if you do a search
at this and other forums
you will find over a hundred posts
where Ram owners have had pinion bearing failures on the 9.25 differential
and since about 2002 the SureGrip option has had many clips breaking off.

I have had my 9.25 rebuilt at 40,000 miles and at 160,000 miles.
At the 40,000 mile rebuild the truck was just out of warranty and I had complained about the noise before the warranty expired so that the Chrysler Regional representative offered to pay half the cost of the $800 rebuild, and he remarked to me that it was a common problem with the 9.25 diffs being made in the 1990s.

In the 1980s the 9.25 diff did not have this failure problem.

My best guess of the 'root cause' of the problem is that the big nut that pre-loads the pinion bearings is not staying at proper torque, and when it loses the pre-load the oil seal fails and the pinion bearings 'chatter' themselves to death shortly there after.

As a replacement rear end
there are some 5 on 5.5 axle end pattern Dana 60s
in junkyard International Scouts, some Dodge pickups of the 1980s.

The 5.9V8 2500 Ram pickups of the 1990s have Dana 60s
but you would need 5 on 5.5 axles
and the rear leaf spring mounts would have to be modified.

The Cummins and V10 2500 series Rams have Dana 70s
which are a little odd.

Because of its high use in NASCAR
the Ford 9 inch differential has been extensively tested and improved
and a custom axle with that
would probably be a 200,000 mile durability unit
if built by a good shop.