REAR-END ?? MAYBE ??

[MIDNIGHT RIDER]

I just returned from a 500 mile cattle haul.

The last hundred miles, a "popping/lungeing" started in my truck, when turning hard to the left.

Turn right, everything is fine.

Turn left, popping noise and lurching of truck.

I made it on in, got the cattle off, and got the trailer back home.

Too dark outside, and I am too worn-out, to start examining.

What are the likely suspects.

Rear-end is a 1985 DRW Dana-70 with 3.55 gears, limited slip, and half a million miles.

Around three months ago, I removed the cover, examined all gears and bearings, and filled with Valvoline 85W-140 lube.

Other than the popping when turning left, there is no gear noise, whining, singing, ringing, or grinding.

Where should I look first??

Thanks.

 

[highest_vision]

Front suspension - ball joints, radius arm, everything that changes geometry with a left hand turn. Radius arm bracket can crack, don't know what kind of noises that makes though. Just replaced them...
James

 

[sassyrel]

as hv said--aint the rear axle--start engine--have someone turn steering wheel while you watch parts--youll find it---

 

[Freight_Train]

Well,the lunging sounds like a rear end.You said you had a Limited slip.Did you add the needed stuff for the clutches or whatever is in there?My idea is you may have trashed or lost your Carrier causing this problem.When you turn the outside wheel moves faster than the outside.Maybe one side is working correctly and when you turn Right the good side is working fine and the other side is freewheeling but if you turn left the good one is freewheeling and the other one is catching and letting go kinda like what happens when you make either turn with a true locker.in out in out in out.I would say pull the cover and have someone one each wheel turn them different speeds while you watch the innerds.You could have also lost a tooth on a spider gear.Sounds like it could be the spider actually on the axle shaft itself.

 

[MIDNIGHT RIDER]

Freight Train, all those diagnosis sound kinda expensive.

When I get the trailer loose, I am gonna jerk the cover and have a look inside.

I am just proud that the old gal held together long enough to get the cows home.

I didn't put anything in the differential, except 85W-140 lube; but, for as long as I have owned the truck, many many years, I have never added anything except that lube.

I am almost positive the problem is in the rear-end.

I wish it would be something as simple as a control-arm.

Thanks.

 

[sle2115]

I didn't put anything in the differential, except 85W-140 lube; but, for as long as I have owned the truck, many many years, I have never added anything except that lube.

Did you use the exact same brand this last time? The reason I ask is that some come with the limited slip additive already in it, some don't. Sure sounds like a limited slip clutch pack problem, but it could be that it just wore out, they do that. Most OEM clutched differentials are clutched on the loose side for liability purposes and slip rather easily. This makes them corner better etc. but also makes them wear out, just like slipping your drive clutch will do.

I would say do as you planned and get the cover off and have a look see. Catch the differential lube and "feel" it might find particles or even metal grindings in it that could help diagnose the problem.

 

[Freight_Train]

If you want to get creative you could take a powerful magnet(if you Neodyniam if possible) and stick to the outside of the cover as low as possible and drive around the block a few times.This way when you pop the cover the oil drains and you can look and see how much metal has collected on the other side of the magnet.

 

[smokin_stroker00]

what are the chances the clutches are any good after 21 years anyways.
The ones in my 2000 nolonger work and that is only 6 years.


It sounds like what a u joint in the axle joint does when it is bad

 

[Agnem]

That's what I'm thinking. The limited slip is probably VERY limited by now.

 

[MIDNIGHT RIDER]

If it is only the Limited Slip going bad, is this something that is going to eat my rear-end; or, can I somehow eliminate it and drive on??

When I recently changed the lube, I scrutinized everything, closely, and it all looked good.

I haven't had a chance to go inside; that may answer the question, once and for all.

Thanks.

 

[Agnem]

Have you tried jacking up the rear axle, and just mess around turning the wheels by hand? Maybe you will feel or hear something.

 

[MIDNIGHT RIDER]

No less than five different truck-owners, after hearing me describe what my truck was doing, told me that they had experienced the same problem, and that simply adding a bottle of whale-oil, or limited slip additive, completely cured their problem.

I drained the fluid and pulled the cover, tonight, to examine everything.

Everything that I could see looked as good as new.

With someone turning the wheels, I closely inspected every tooth.

I sealed it back up and pumped in the lube.

I have one more minor issue to address; then, I will squirt in the bottle of limited-slip additive that I bought.

Then, I will see what happens.

Just so I don't get caught with my drawers down, I intend to buy another rear-end and rebuild it completely, to keep around as a spare.

Then, if I am a long way from home and a rear-end gives up on me, I can simply call home and have an entire rear-end loaded and on the way.

Thanks for all the ideas.