Dana 60 problem

I have a dana 60 under a car. it has been shortened and rebuilt.

I put the car in reverse and it tries to move. in neutral it unloads like it should. in drive it rocks forward then nothing. just free revs.

I blocked the wheels and looked under the car with it in drive and a friend on the brakes. the driveshaft was spinning, we rev it the DS spins faster the car won't move.

I pulled the diff cover and had it on the wheels, started the car and put it in gear. the diff is rotating like you expect to see it... except the wheels are not moving.

I pulled the axles and there is a TON of spline engagement. I can barely spin the driveshaft in neutral wheels on the ground and the car off, but i can get it to rotate.

So this means the diff is bad?????


Help

Also- is this a stock differential unit?

Yes it is broken, take it apart to find out what is broken

Sounds like the posi is missing some plates or it was not assembled correctly
That is the good early Dana 60 clutch type posi
If you are able to work on it yourself, rebuild the posi, check the current backlash and then remove the posi with the ring gear on it and mark the two halfs of the posi case before taking it apart to inspect it so you can reassemble it with the cases aligned properly. All the stock Dana 60 clutch type posi have two beveled clutch drive plates, the rest are flat I don't remember which way the curved plate install, towards the ring gear or towards the axles tubes Buy or borrow a good 1967 to 1971 B body FSM and use it for your information on that unit and how to repair it properly
maybe it is something really stupid like the wrong clutch plates in the posi unit for the axle splines
I remember being told years ago to remove the bevel plate and used a straight plate instead to help reducing friction in high gear for a drag race only rear end, the one thing you had to do after backing up was to make the car go forward 5 or 6 inches minimum to reload the friction plates before getting on the throttle hard
IHTHs
Mark the caps also so they go back on the proper side installed correctly

Like said above, somebody left one, two or all disc plates out.

Is this a fresh job? Or is this something that broke?
How do you know there is a ton of axle engagement?
Do the axles rotate by hand? Can they be rotated independently of each other?

Looking at the pin, it's not sitting in the bore very tight. It also looks like the pin is flattened out on the bottom. Doesn't look right to me?

Is the housing offset? Is the right axle in the left side of the housing? That would be the only thing that makes sense to me. This would cause the car to “try” to move. That condition would be relying solely on the single side diff clutches to drive the car. The clutches are not enough to drive the car. It needs both axles to engage the side/ spiders. Also of note, the spider pin rides on a ramp that increases clutch application, assuming both axles are loaded against the diff case.

I pulled the axels out and can see the oil line on the spline. it is 1 5/8" engagement.
This was a "fresh job" almost 15 years ago. it has been sitting. the shop is no longer and the guy moved out of state. he was very reputable chassis builder. Lots of cars running around he built. I'd chalk this up to an mistake.
with the wheels on, and off the ground and the trans in neutral the drive shaft will spin both wheels.


I won't be able to touch it for a few days, but ill pull it out and part and post up a few more pictures.

That’s a terrible “mistake”.

I'm not clear on what would cause a rear end to act like that but it seems to be either broken or else it was put together wrong. Not sure how come it wasn't noticed for the past 15 years. Wasn't the car ever driven after the rear end was worked on? Usually the car has to be moved around the shop or driven on a trailer or something.

Even if it had no clutches in it, it should still move...or am I missing something?

Cover off? Stick the axles in and try to rotate the rear with a bar stuck in the studs. Gotta have the wrong size axles in it or the teeth cleaned off of a spider gear.

The fact that it tries to move, tells me that only one axle is engaged in the side gears. This would allow the clutches to slip enough to seem like it wants to move the car, but not quite be able to. It’s the only explanation that makes sense to me. If the clutches /plates weren’t in there, the cross pin would be flopping around. In the pic, the cross pin is sitting on the ramp as it should. I have to assume that the clutches are there based on that picture.

My bet is an early suregrip unit with 2 piece side gears and the axle is only in far enough to get the clutch plate, but not the gear that engages the spider/ pinion gears. It happens a lot at chassis shops that do not know danas are offset, they measure the short side and order axles, exact symptoms you describe. Late clutch type diffs had one piece side gears so they could "slide" by with that kinda work. I did a trans for a guy, car would not move on the ground after narrowing the rear, of course blamed the trans, nope, one axle too short, by a bigshot chassis shop.

i got home earlier than anticipated today so i was able to get a little more done.

I shoved both axles in the housing with the diff in, there is a good mount of spline angagement. With the brakes off and the trans in neutral i spun the driveshaft and both axles spin. if i spin one axle the other one moves too. it works as it is supposed to by hand.

The axles are not equal length. Driver side axle is 19 7/8 pass side is 17 5/8". or close to that.

The chassis guy is a mopar guy, he ran mopars for years and years.

I pulled the diff out and have it on my work table. I will hopefully pull it apart tomorrow after work.

The car went to the chassis shop, came home and sat in the garage a bare shell for the last 15 years. I decided to get it going for my uncle. All he has to do is pay for parts, im donating all my labor.

I loaded it on my trailer with my winch and had 3 guys help me get it into my driveway. this was the first attempt for it to move under its own power.

Even with destroyed plates, input in should result in rpm out.

If you have input in as as far as driveshaft speed and nothing out, it's much worse than any diff clutch. Even completely open would result in outside shaft rpm....

what style unit it this?

I've got a sneaking suspicion this unit wasn't rebuilt!

yea its bad

Are the side gears 1 or 2 piece? Doctor diff has a kit to fix that

im not sure i know what you are asking. are the little gears one unit? or two? is that the question?

No, I mean the gears the axles slide into. I also see heavy wear on the spider gears, and thrust spacer, like it was run with too long of axles and green axle bearings with one axle, likely the right side pushing on that thrust block. How about a pic of the axle, axle bearings and the side gears that slide on the axle. If it has greens you may need to.remove that thrust spacer, or at least make sure you have 3/16" between it and the axle on each side.

ah yes, they are 2 piece.

does this matter????

Ok that is likely your problem, how many splines? The kits doc sells are the late one piece gears. In any case you need new internals from what I can see, if one axle is not in the second gear splines car will not move but tires will turn in the air.

Looks like the chassis shop guy did a shoddy job and got lucky since nobody tried to drive the car for 15 years. That is a bummer but it can all be fixed. Just going to cost some money and some time.

What spine axles are you using?
I think all the early, pre 35 spline axles Dana 60, had the two piece side gears, I saw the first one piece side gears in a 1970 E body Dana 60.
I have also seen a original 23 spline Dana 60 in a early production (assemble in early Oct of 1969) V code 1970 Charger RT 4 speed car with 4.10 gears
Don't feel bad on this it is not the first time I've seen guys put the wrong axle in the wrong side in a race Dana 60
Order a rebuild kit from Cass at Dr. Diff to replace those bad clutches and drive plates, make sure the axle engagement is correct also

None of your pictures show lube on anything. How far were you going to drive it with no lube? Or is this damage the result of driving it with no lube?

Was questioning too why the ring gear is dry.

Also, are you only showing one set of clutch packs? There should be two sets. Show both sets.

You can actually see the gear oil draining in the first picture. It wasn't dry although it certainly looks that way.

Both sets are shown. The are both identical, smoked.

The clutches can be absolutely worn/ used up and the diff should still transmit power to the axles. The clutches only function is to keep axle speed the same. You have an axle engagement problem.

Make sure the axels touch the pin in the center, then get a new clutch pack. Then make sure they’re installed in the right sequence.

i reassembled the diff, put it back in the housing.

put a tape measure in the driver side axle tube, down the splines into the button and then compared it to the axle. the axle is within 1/16th of an inch
i left the axle in and measured the passenger side, down the axle tube, through the splines and touched the pin. the axle is almost 1/2" shorter than the measurement. I guess ill be upgrading to 1 piece gears.

That will fix it, what spline do you need?

30 spline

I have a 3 series 30 spline early Dana 60 posi I have never taken apart, I'm thinking they came with the two piece interior posi parts like the 12.17 and 23 spline posi came with stock
I'll try and remember to dig it out tomorrow and look inside to see if I can tell if the side gears are one piece or two piece
Maybe call Cass either way to check if he can help you on this or not

Ok, not sure if they have reasonably priced 30 spline one piece side gears for dana 60, 32 and 35 for sure, you may have to find spicer parts not yukon. If you look online most gears for sale are for non powerlock diffs so be careful. I don't know what axle bearings you have but you need to use greens with that short axle for sure, and make sure they are the later snap ring style. Cass can fill you in on all this, it might be best to go 35 spline internal kit and new axles, about $600. I would check the diff bearings too, as all that metal may have went thru them, at some point in that ring gears life. You could also buy new axles and reuse the 30 spline stuff.
30 spline 1 piece gear is spicer 34513, the friction plate is 42522, you will need both.

I can't seem to find the 34513 parts anywhere.

Cass at DR. diff said its a no go for them on the 30 spline parts.

It looks like it will be 615$ OR SO to replace both axles, and rebuilt the diff with 35 spline stuff.

Ideally id like to go get a 30 spline axle cut down 5/8" longer than what i have. Ill have to ponder this a bit more.


or i cut 1/2" out of the passenger side axle tube, adjust the housing an1/4" over to split the difference and make it work like that. I have the room on the inner wheel tub..... I also have a dana 60 narrowing JIG.

Yeah that is a problem with picking up a project after 15 years. Sometimes the stuff used in the build is no obsolete so you end up starting over. I've been down that road a few times.

I’m not sure what spline it is but I have an nos sure grip from a Dana 60 truck. It the newer version like 71 up. I think it’s called a power lock? I can look at it and see if it would help you out. I will sell it worth the money.

I learned about the 30 spline Dana 60 when a friend bought a junkyard Dana 60 pickup(1970 GMC) I think, and had it narrowed to go under his 1968/69 Plymouth Road runner, we used his 8 3/4 axle in it along with the brakes with no issues. back then he and I didn't know that wouldn't work

I'd get a spool for under $200

Remember the center pin piece will move back and forth 1/2 inch. Stick the axle that was close back In and tighten down, then measure the other side again. Does one axle have an adjuster?
No factory car Dana came with 30 spline, 23 66-69, 35 70-71. 30 spline went in trucks-vans with floating ends, 8 lugs

This rear end housing was a bare housing given to the chassis shop. he cut it and "built it". No idea what any of it came from.

This vehicle is a pro street car, but it will definitely be more street than strip.

I think the ticket will be to buy one axle and have it made to fit what i have here.

The pin does move and when it was pushed all the way to the passenger side is when i took that measurement. if i push the pin to the driver side it increases!


maybe i ca find an ol 8 3/4 axle shaft laying around and have it cut down?

My Dana 60 has a spool, and maybe 20 years ago when my uncle started the project he would have gone that route, now in his late 60's he is looking for more "street"

Try and find a C body 8 3/4 or a E body axle, they are the widest stock rear ends and thicker from the splines out to the wheel bearings, try and make sure to use the axle from the side you want to use on your car, IE R/H axle on the passenger, driver side on the driver sides, DO NOT reverse them

I don't think the chassis shop guy did you any favors. Looks like he put used parts in the rear end and did a poor job of measuring things. You might want to double check all the other work he did on the car.

Its funny you say that. I was looking at his metal work under the car, and I am by no means a professional welder but my overhead welding is substantially nicer looking.
His cage work is very nice, and you can tell he is a skilled welder.... maybe he thought nobody will ever see the bottom who cares.
Bolts were missing on brackets, only 3 bolts holding the axle retaining plate on the driver side, 2 on the passenger side. Not sure what happened. I know a few people who had their chassis done by this guy and had nothing but good things to say. Even his old machinist who he had a falling out with still reccomended him!

I bought a car once that had been built by a local chassis builder. Everyone I talked to raved about the guy's work. The car I bought was a pile of crap and almost all of his work had to be cut out and redone. So I'm not sure what to say other than I guess it happens. Maybe the chassis guy knew it was a long term project so he just cut some corners on it. At this point you'll just have to double check everything. Nothing else you can do.