Dana is not performing with Royal Purple

[Sweet T]

Changed the oil in the Dana60 with Royal Purple(no extra's).  Put about 150 miles on it, took it to the track ran a few passes and drove it back home without any issues.  Now the car goes flat on the acceleration and the rear end is making some noise.  It almost seems like the rear end is slipping if that makes any sense.  The revs from the motor increase normally but there's no power hitting the pavement?

[firefighter3931]

That sounds more like a transmission (slipping) issue to me 



Ron

[62 Max]

I always wondered  why people change things that work.What did you expect to gain over a good sure grip gear oil with an additive?

[62 Max]

I just knew the oil was at least 20 years old, it not 39.

But it still worked!

[SeattleCharger]

Instead of helping to answer his question, I will kick him while he's down. 

                                      
                                                                                                 

[62 Max]

Instead of helping to answer his question, I will kick him while he's down. 

                                      
                                                                                                 

Then I'll put it this way.Does your Royal Purple have the addatives for sure grip requirements or is it just a gear lube?  If it is the rear that is slipping  and it was ok before you changed the lube that should answer your question.

[SeattleCharger]

dam I am so righteous, heh                 J/k

[Ghoste]

So backing up then, I agree with Firefighter.  The rearend can have a lot of failures and certainly a "slipping" condition can be among them but it would basically mean that teeth were stripped off of the pinion, ring gear or axle ends.  A limited slip device can also slip and fail but it will still allow the vehicle to accelerate and move forward.  At it's very simplest, the rear end converts the rotational movement 90 degrees to get it from the driveshaft to the tires.  Yes, it does a lot more than that but that is at it very basic function.
On the surface, the symptoms you describe tend to make one look to the transmission just as Ron mentioned but since you also mention noise from the rearend, I guess the first thing I would do is try to make sure about that.  Have you jacked the vehicle up and tried turning the wheels to see if there are any rough or noisy spots in the back? (that isn't a sure indicator if there aren't by the way)  Does the driving noise seem to be a clunk or a whine or just what?  Is it only on acceleration or cruise or decel?  Is it a Sure Grip?  You said you took it to the track and drove home with no issues so just when did the issues arise?  Were they preceded by noise or abuse?

[firefighter3931]

What everybody is missing here is that even if the suregrip fails you still have a single track rear end and it won't behave as described above. The only scenerio where it could possibly duplicate those conditions would be as Ghoste described....stripped splines or broken side gears. In that case the car whouldn't move at all...

Royal Purple is supposed to have suregrip additive/friction modifiers built into the formulation. Personally, i'm not a fan of synthetic fluids in a clutch style 3rd member. With a Locker i would have no problem using it.


I'd be looking at the clutch and pressure plate. 




Ron

[Sweet T]

As always guys thanks for your help and input (except 62 max.....there's more constructive ways to get your posts up ).  Gave everything another check over and took her out again only to find nothing wrong

[resq302]

Maybe the clutch was heated up a little too much causing it to slip a bit?   I was in traffic a couple weeks ago coming home from a show in stop and go traffic and my clutch seemed to be slipping a bit once I got out of the stop and go traffic.  Needless to say, my left leg to a work out but the next time I took the car out, it was fine like you said.

[Runner]

Instead of helping to answer his question, I will kick him while he's down. 

                                      
                                                                                                 

Then I'll put it this way.Does your Royal Purple have the addatives for sure grip requirements or is it just a gear lube?  If it is the rear that is slipping  and it was ok before you changed the lube that should answer your question.

   so you dont ever change you engine oil or tranny oil until theres a problem???  and yes royal purple is fine for a suregrip. cone or clutch. 



  glad to hear everything is working fine for ya now sweet t

[Ghoste]

I'm glad to hear the car is working good again but it seems a little strange that a "slipping" sensation and a noise have both gone away.  What kind of noise was it coming from the rearend when it was making one?

[62 Max]

Instead of helping to answer his question, I will kick him while he's down. 

                                      
                                                                                                 

Then I'll put it this way.Does your Royal Purple have the addatives for sure grip requirements or is it just a gear lube?  If it is the rear that is slipping  and it was ok before you changed the lube that should answer your question.

   so you dont ever change you engine oil or tranny oil until theres a problem???  and yes royal purple is fine for a suregrip. cone or clutch. 



  glad to hear everything is working fine for ya now sweet t

This started out discussing Dana rears,not engines and transmissions.And yes,a clutch type sure grip can slip or chatter without the correct gear oil epically on turns.I doubt they were designed for synthetic fluids.Actually at that time i doubt if there were any.Today you are working with 40 yr old drive trains that were designed to work with the lubricants of that era.Todays vehicles and lubricants are a whole new generation.Everything is made in much closer tolerances and the reason for synthetic fluids.Starting somewhere in the late 80's oil change interval for most vehicles was 7,000mi.Today some are higher.Mercedes recommends 10,000 mi.Most cars can go 100,000mi before a tune up.These don't apply to 40 yr old cars.

[Spike]

A synthetic gear lube will work fine in our cars as long as the sure-grip unit is in good working condition to begin with. If you have burned up or worn clutch disc the change to a synthetic lube will not help you one bit.
It is also suggested that once you change your gear lube to synthetic that you drive your car in a figure 8 pattern a few times to work the new lube into the sure-grip clutch disc. This goes for any vehicle changing to synthetic gear lube.

[SeattleCharger]

 . . . just curious, I wonder if that "Lucas" line of products has one for differentials.  I know they have decent engine oil additive, transmission stuff, fuel injector cleaner, power steering stop leak, etc.    Some sort of product to maybe get a little more life out of the thing until a person can afford to repair their car right.