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mx_599

Loadstar 3-speed axles

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I have not been able to acquire any manuals yet and just have a few basic questions on these:

1) Can they be shifted/changed on the fly?

2) can you swap and change to taller gearing on one of the three speeds to get improved highway speeds? Can you swap out the tallest at 6.14 to something in the low 4's or can you never change the gearing ratio of either of the three speeds?

Thanks!

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They're basically the same for shifting as two-speeds, according to the owner's manual. If you swapped a gear ratio, you'd have to do all three to keep the shifting step the same, I imagine.

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They're basically the same for shifting as two-speeds, according to the owner's manual. If you swapped a gear ratio, you'd have to do all three to keep the shifting step the same, I imagine.

Oh okay. Well I don't know the two-speeds either! lol

So you're thinking if all three are changed that you can? Is anyone aware of reading if someone has put a groupset of taller gears in the RA-351 axles?

thanks

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Dad drove for a livestock hauler that had a '64 Emeryville with 220 Cummins and 5+3 transmission.  It was geared plenty fast the way it was built.  Would run 65+ mph empty.  I would imagine it's really hard finding usable drive axle parts in salvage yards for 50+ year old trucks.  Converting to single speed axles and overdrive transmissions like used in trucks today would be much quicker and more reliable, probably cheaper too.

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Never heard of a Three speed axle?? Do you mean a auxiliary transmission ??all ways though a truck that had a 5+3 was a 5 speed transmission with a 3speed auxiliary box between trans and rear axle !!  learn something new every once in awhile !

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They were tandem axles with a 2 speed in both axles....so both in high=high, both in low=low, 1 in high and 1 in low thru the inter-axle differential=intermediate speed.  As you can imagine they didn't work very well and were very hard on the inter-axle differentials.  I can't imagine, as any 2 speed I've had was not very reliable, having 2 in the same truck would be interesting.

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Thanks for replying guys. Well, now I am confused? I thought it was gears within each of the two axles....no? And it is listed as 3 speed.

So could one convert the the gears only with modern single speed gearing?

thanks!

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3 hours ago, farmall57 said:

They were tandem axles with a 2 speed in both axles....so both in high=high, both in low=low, 1 in high and 1 in low thru the inter-axle differential=intermediate speed.  As you can imagine they didn't work very well and were very hard on the inter-axle differentials.  I can't imagine, as any 2 speed I've had was not very reliable, having 2 in the same truck would be interesting.

Maybe I am understanding more, just reread your post. the 3-speeds are:

1) high high

2) high low

3) low low

Is this correct? do you know if you could replace internals to just a single taller ratio for higher speeds combined with newer over-drive transmission?

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See, the two-speed rear axle has two mechanical wonders: the differential and the planetary. Model Ts had a two-speed planetary. Would it be possible to have a three-speed planetary?

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22 hours ago, CONN said:

Never heard of a Three speed axle?? Do you mean a auxiliary transmission ??all ways though a truck that had a 5+3 was a 5 speed transmission with a 3speed auxiliary box between trans and rear axle !!  learn something new every once in awhile !

Eaton made a 3 speed axle set. Place I drove for had 2 of them, one with a 534 ford and and 5 speed main box for a total of 15 ahead.

The other had a 220 Cummins, 5 speed main & 3 speed rears.

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drove a gmc with a 3spd electric shift axle Eaton I believe.

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hello all, I have purchased a 1968 Loadstar 1600 and I was told it has the 3 speed rear end. There does not appear to be any wiring or linkage to the rear so it would seem the multispeed function is disabled. I was looking for some sort of id plate or stamped number and have not been able to find any. can anyone advise where the axle info would be located, and does anyone have a picture or diagram of the actuator for the multispeed rear end? My truck has tandom axles and they are connected with a driveshaft out of the top of the forward axle. Right now it appears only the fromnt axle is being driven. Also, what weight gear oil was recommended for that rear end?

 

Thanks,

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As IH built 1700 and 1800 Loadstar tandems  I believe your tandem was added a picture of your set up would be very helpfull.

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I have two IH with twin screw rearend trucks that have auxiliary transmissions. You can only get two speeds in the rear ends on any trucks.  Any more than two require another transmission. Speeds are set up like in another transmission. 1 being the lowest and they get faster after that. On any twin screw rear end, only axle drives unless you activate the power divider. You only do that when you are about to get stuck. 

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that eaton 3speed  was a very unique unit   saw A FLEETSTAR like that back in the mid 70s also

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sorry no luck uploading pictures. maybe someone can help me out?

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Is that some kind of kit to make a twinscrew  out of a single axle?

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3 hours ago, bitty said:

Is that some kind of kit to make a twinscrew  out of a single axle?

never thought of that, and it could be. i wondered about the "cutout" in the frame crossmsmber for the drive shaft between the lead & trailing axles. on the rear axle, there does not seem to be anything to suggest 2 speeds in the rear end.

So if this is an add on power divider, would I be correct in the little lever at the front is the locking mechanism to lock in the rear axle?

 

Thanks,

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Totally guessing ,,,    The main d-shaft enters that "box/ power divider"  kind of offset from the center ,  What I am trying to say is ,

I wonder if the box is a 2 or 3 speed unit ??      I will take a peek in some of my old Motors manuals and see if anything pops up

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Many Moons ago, I looked at a D series IH truck that had a lever operated two speed rear end. Until that day, I had osnly seen vacuum or electric operated. The 3 speed rear end is something I have never seen before. Others have, just not me. The D series was a single axle. Truck was a mid 1930's I think. 

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Picture 4 of the first 4. It finally let me post it.

loadstar1600h (Medium).JPG

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