Transmission or rear diff. problem

[ijg4503]

Hello,

I have a 70 Duster 340 4spd. I seem to be having a problem with either the A833 trans adjustement or the rear diff. When I launch the engine revs up and it sounds like the wheels are spinning, but they are not. It's almost like traction control. The clutch is fairly new so I am not sure if it's slipping beacasue something is out of adjustment since I rebuilt the Zbar assy?? Or could it be the sure-grip unit clutches slipping and the unit needs rebuilt?

Also, the rear end howls a lot due to some pitting on the ring gear. Does anyone know any Mopar rear diff. guys in the Atlanta area that could rebuilt the 489 case for me?

Thanks,

ijg4503

 

[pettybludart]

Sounds like your rear is Toast!Is it clutch or cone type?You can get the clutch type rebuilt!

 

[mopar340dave]

1. Remove the plug from the rear and see if any oil comes out. If none does, stick your finger or a clean small piece of hose in and pull it out. When you do this, keep your fingers about 2" from the end of the hose that you stick down into the hole (the fill plug is on the side of the gear case) so you can judge how much oil is actually in it. With the car on level ground it should be flled up to the hole. If 2" inches is not enough to dip it into the oil, try filling it with some 85w90 gear oil and see if it helps.

2. Pull the inspection cover off of your clutch and take a look. If there is excessive dust from your (new) clutch, that is probably your problem.
What clutch did you install? A Centerforce Dual Friction requires the removal of the over center spring from under the dash. If this is the case with the clutch you installed, regardless of brand, you will need to remove the spring. The manufacturer of your clutch can tell you if this is the case.
If this is the case and you have not removed the spring, your clutch will not fully engage because the over center spring applies more pressure than is required to slightly depress the clutch.

What gears are in it?
The taller the gear the more they seem to howl.

 

[ijg4503]

I just restored the rearend and 489 case. I cleaned it up and refilled it with lube and the sure-grip additive. It is full to the plug. I am pretty sure it id a clutch type SG unit since you can see down inside the housing and see the springs, etc. I will pull the inspection plate and check things out. It has a Ram clutch and 3:55 gears. I assume that the howl is a result of the ring gear having pitting on it. It is loud (really loud) at speed.

Thanks for the advice.

Jason

 

[demon seed]

I just restored the rearend and 489 case. I cleaned it up and refilled it with lube and the sure-grip additive. It is full to the plug. I am pretty sure it id a clutch type SG unit since you can see down inside the housing and see the springs, etc. I will pull the inspection plate and check things out. It has a Ram clutch and 3:55 gears. I assume that the howl is a result of the ring gear having pitting on it. It is loud (really loud) at speed.

Thanks for the advice.

Jason

If you can see the springs in the diff. it's a cone type and I doubt that pitting on the gear is causing the howling. I'd be willing to bet that the howl is caused by incorrect tooth contact and should be checked or serious damage could occur. http://www.moparts.org/Tech/Archive/axle/13.html

Terry

 

[fishy68]

Does your speedometer work? If so you have a tool to diagnose which part isn't working right. Just look at the speedometer when you floor it and if it's going up but the tires aren't spinning and your not moving much it's the rearend slipping. If the speedometers not going up that means it's the clutch slipping.

The howling can also be caused by a bad bearing. Either one in the 3rd member or an axle bearing can howl. Like DemonSeed said you need to get it taken care of right away or you may be looking at a much bigger repair.

 

[mopar340dave]

Good thinkin' fishy!

 

[fishy68]

Good thinkin' fishy!

Why thank ya sir.:-D

 

[ijg4503]

Thank you fine gentlemen. I am getting a lead on a local rearend guy tomorrow as well as someone who can restore my correct radiator.

ijg4503

 

[ijg4503]

Well boys, I am hosed. I had a local Mopar mechanic take my 489 case apart and it is toast. He said it is very bad and the only usable parts are the case and yoke. To say the least, I am not very pleased with the guy that I bought it from in KY. I am out $400 and need to find a good Sure-grip unit and either 3:55 or 3:91 gears. If you have any leads on a good sure-grip unit and gears let me know.

Let me know what you think.

Thanks,

ijg4503
(614) 946-3333

 

[fishy68]

Man that sucks. You may want to place a want ad. Somebody probably has something for sale. Here's a hint when buying. The 489 case is a very strong case but almost all 489 units came with the cone type sure grip which isn't rebuildable. The 741 and the 742 cases all came with the better clutch type sure grip unit that is rebuildable. You can take the sure-grip out of any case and put it in the other though so make sure it has the clutch type SG. You can tell it from the cone type easy because the cone type has springs that are visible through 2 little "windows" on each side of the unit where-as the clutch type don't.

 

[ijg4503]

Thanks for the info. I am looking to buy the parts to rebuild the 489 from Diffdoc on Moparts. I can have my local Mopar mechanic rebuild the unit once I have all the parts. I definitely have the cone SG because I have the openings to see the clutches.

Thanks again,

Jason

 

[fishy68]

Ok but as I said above the cone type isn't rebuildable. It's called a cone type because it uses cones instead of clutches to apply torque to both wheels. Only clutch types can be rebuilt.

 

[ijg4503]

Yeah its a cone type. I have to find a new SG unit.

Thanks agian,

Jason