help w/ Yukon axles & thrust spacers

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swinger 367

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i have just installed LBP Yukon axles on my dart and i have a 742 case with 3.91 gears and the Dana Power Lok (clutch type) sure grip. do i have to remove the axle thrust spacers? if so how? they seem to be deep in there. also does anyone have an easy way to remove the pinion nut? i want to swap out yokes small for large. thanks
 
You shouldn't need to remove the spacers.

Those nuts can be a pain. A good impact wrench should work. Make sure you get the new nut torqued correctly. Are you switching because you're switching to a new driveshaft, or for a stronger u-joint? I would use a conversion joint unless I HAD to switch to the larger yoke for some reason.

As a not of caution, be VERY sure that the spacers are in place, or removed. Don't ever chance having one fall in the housing. If one is sitting down in the fluid, there's a good chance that it will get sucked up into the gears while on the interstate when you're driving 85. It makes a really neat *BANG* noise, and jerks hard, and puts a cool hole in the back of the housing. That was the only time I had ever paid someone to do that swap for me, and look where it got me.
 
the spacers are in place, the thought of them having fell out is what made me pull the pig today. i figured that a little chunk of metal loose in the diff might not be good.

the yoke swap is because i think that i'm going to get a new drive shaft. i cut the old one a little too long (less than 1 inch) and i'm not sure it's salvageable. on a new shaft the difference between large and small is $10, i have both pinion yokes so i figured that i would go large. i need a new pinion seal anyway.

i understand that the 70's a body 340 cars came with small u-joints, are the large joints significantly stronger? or is it just perception. what are most people running?
 
There was a thread here just recently that said you do have to remove the spacers I think otherwise the axles won't go all the way in. Search here in the trans. section and you should find it. just been in the past few weeks.

It isn't the width of the joint that makes it stronger but the diameter of it. The caps measure 1.078 on the small joint and 1.126 on the big joint. That's only 4-1/2 % larger. Some stronger but not alot is my guess. Get the best U-joints you can for the 7260 and it's probably just as good or better than having the 7290 with stock u-joints.
 
I know this thread is a couple months old but I figure some guys can learn something about whats going on.

When I put Green axle bearings on my 72 swinger with factory SBP axles and a 742 case suregrip I had to trim the axles a touch because bolting the axles in with the green bearings caused the axles to clamp the thrust button in the pumpkin and it totally locked the rear tires together, tires squeeling around corners and everything, took the axles to a guy and he put them in a lathe and trimmed a bit off each one. Everything worked well after that.

I had read somewhere's that the axles had to be shortened by a certain amount to run those bearings.
 
Brambles said:
I know this thread is a couple months old but I figure some guys can learn something about whats going on.

When I put Green axle bearings on my 72 swinger with factory SBP axles and a 742 case suregrip I had to trim the axles a touch because bolting the axles in with the green bearings caused the axles to clamp the thrust button in the pumpkin and it totally locked the rear tires together, tires squeeling around corners and everything, took the axles to a guy and he put them in a lathe and trimmed a bit off each one. Everything worked well after that.

I had read somewhere's that the axles had to be shortened by a certain amount to run those bearings.
Click to expand...

I haven't read that but I have read that you need to remove the thrust pins to use the Yukon axles. Maybe same effect???
 
I'm not sure if its the same problem or actually two problems.

I don't have a set of each to see if the yukon axles are longer than the Factory A body axles by a bit.

If they are the exact same lenght then its all to do with the Green bearings and just trimming the axles a bit on each end will make it so you don't have to remove the button.
 
Do you still have one of your axles out? If so I have a stock axle out and we can compare measurements just so we all know.
 
I tell you what!, I just ordered a pair of yukon axles and when they get here I'll measure them up and we can compare the differences in overall lenght.

I'd be interested to know if there is a slight difference, I've seen the axles on different sites stating "factory lenght A-body" and some say its 28" and some say 27"and change...
 
I have a set sitting in the shop. I'll try to measure them tomorrow.
 
i didnt remove the spacers in my 3.91's but i have moser axles. havnt run it yet either. but the guy who had the gears before me ran it with the spacers in with moser axles too...not sure if this helps...
 
he ran it with the axles and had no problems. i called him for the same reason you had....he heard it too but didnt have a problem...again these are with moser axles
 
I measured a stock axle today and from the surface where the brake drum contacts to the end of the splines is 27-11/16" plus or minus 1/16". It wasn't easy getting an exact measurement.

Brambles you might be right about the fittment problem only being with the clutch type unit. I know you can remove the thrust spacers on a clutch unit fairly easy but I'm not sure about the thrust block on a cone type. I know there quite a bit different and if I remember right you'd have to totally disassemble the unit to take it out. Maybe it's a little narrower than the thrust spacers were and it wouldn't be a problem???
 
Im trying to remember the details---but i had a set of Yukons that were in my 742 case with clutch type sure grip. It was recommended i remove the thrust button so they would engage the splines deeper? Sorry its been a while---

I did that while the pig was out to be sure.

Mine measured 27.75" from the splined end to the back of the big flange. Green style bearings



The answer can be found at moparts--the screen name DoctorDiff . He's the Yukon dealer where i bought mine .

Sorry i cant remember the details---------STUPID ALZHEIMERS !!
 
496dart said:
Im trying to remember the details---but i had a set of Yukons that were in my 742 case with clutch type sure grip. It was recommended i remove the thrust button so they would engage the splines deeper? Sorry its been a while---

I did that while the pig was out to be sure.

Mine measured 27.75" from the splined end to the back of the big flange. Green style bearings



The answer can be found at moparts--the screen name DoctorDiff . He's the Yukon dealer where i bought mine .

Sorry i cant remember the details---------STUPID ALZHEIMERS !!
Click to expand...

I've read others that said the same thing about removing the thrust buttons.

If your Yukon's measured 27.75 to the back of the flange and mine measured 27-11/16 to the front the Yukon's must be 5/16" longer. (think I figured that right?) That would explain having to remove the thrust buttons to make Yukon's work right.
 
Curious to see if thats why they claim 25% stronger, not because the shaft is actually stronger but because you have more spline contact???????
 
Probably just made of better metal. There are so many different metals out there today they can probably make them 100% stronger than stock but the cost would likely be much higher due the the metal being real expensive.
 
I came across this quote in my research.....because green bearings don't have the endplay adjustment the axle lenth will be off somewhat.


Note: there was a slight dimensional change in axle shaft length when the Sure Grip design changed. If interchanging axles with the slight difference, the threaded end play adjustment can be used to accomodate it.
 
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