No Power to Rear Wheels

[mpanzar]

So I’m new to the forum world, and scouts for that matter so please bear with me! I have a 1963 Scout 80 and I’m have some transmission/transfer case trouble, I believe. I took it out for a spin and I heard what sounded like a pin dropping in one of the cases. Now I only get power the front wheels. Whats confusing me is that I can still reverse with just rear wheel drive. Any thoughts on where to begin? I have a dana18 with a t90.

 

[Scoutboy74]

Welcome to the forum! Those are some interesting symptoms given your combination of drive train components. It sounds more like something that might be encountered with an automatic transmission. With the twin stick d18, you have one lever for range selection and one lever for rwd/awd selection. Have you tried to see if it will move forward in rwd-lo range? I'm not sure what that would indicate, but I'm just thinking maybe you should try some other t-case combinations and report back with a more complete summary of what does and does not provide forward and reverse motion.

 

[mpanzar]

Thanks!

I think I’ve covered all the possible combinations below.

Awd/hi: hubs locked - forward & backward movement
awd/lo: hubs locked - forward & backward movement
awd/hi: hubs not locked - backward movement only (reverse works)
awd/lo: hubs not locked - backward movement only (reverse works)
rwd/hi: backward movement only (reverse works)
rwd/lo: backward movement only (reverse works)

occasionally when the truck is not in gear just idling there is some knocking in one of the cases.

Also, I originally thought it was a rear differential issue but since reverse works I ruled that one out, do you think that is a correct assumption?

 

[FDChappie]

When you're trying to go forward in rwd, does the drive shaft spin? If not something is wrong in your d18 transfer case.

 

[Scoutboy74]

Thanks for the update. Not sure how much it helps me, but May be of value to someone else seeing this. Next thing I'd try is to get both rear wheels safely supported above the ground. Also being very certain that the front hubs and axle are dis-engaged and the wheels are blocked, see if the rear shaft rotates and turns the rear wheels. Try 2nd and 3rd gears also.

 

[mpanzar]

So I just took a look at the driveshaft and it appears to move in both reverse and in first, second and third gear. I was only able to do short test because I'm waiting on a new carburetor and the old one is in rough shape currently on the truck. Also when the truck was just in rear wheel drive I was able to push it by hand when it was parked in first gear both forwards and backwards and the driveshaft did not appear to move. So I'm back to believing maybe it's something with the rear differential and the knocking I was hearing was the diff. I have a powrlok Dana 27.

 

[FDChappie]

Common problem with a d27 is a broken axle. That sounds like what you've got. The clutches in the powerlok are giving you some movement in reverse. Jack up the rear end, with the ebrake off and trans in gear, try and turn each rear wheel. The one that turns easily would be the culprit.

 

[Robert Kenney]

If you still have the stock rear axle, you have a tapered hub at each rear wheel. They have a large key in the interface that can and often does shear. It only takes one to paralyze you. The hub is fixed by a large nut and cotter pin. The taper is designed to take the torque, not the key. If the nut is not torqued to the proper number, it will slowly beat the key into submission and it will shear. The Dana 27 is small but totally adequate for driving and enjoying your Scout. I recommend removing the pin and nut before jumping overboard and deciding that the dify is dead.

 

[mpanzar]

So I checked last night an the rear passenger side does not sound good! It rotates much easier. Thanks for the help everyone.

 

[mpanzar]

Thanks for the heads up Robert. I am looking in the manual now an I do not see a callout for the recommended torque in the axle shaft installation instructions.

 

[Robert Kenney]

Can you verify that the hub is spinning on the taper?
Pull the nut cover, if it is there, and see if you rotate the wheel and the nut stays still.
As for the nut torque, I don't have access to my fsm and won't for a couple of days.

 

[mpanzar]

Hopefully I can check today or tomorrow. When I give it some gas I can feel the truck wanting to budge forward so I think thats a good sign.

 

[Greg R]

On the Dana 44 in the 800, I use 140 to 160 ft.lbs; that's a 7/8" 14 nut/axle thread (1 7/16" or 36mm socket). The Dana 27 I believe is smaller, 3/4". I would use 100 to 140 ft.lbs.

 

[mpanzar]

I was able to check the hubs last night. The nut and axle spin when I rotate the wheels by hand, on both sides. One thing I noticed is that when the rear end is on jacks and I rotate one of the wheels the other wheel does not rotate in the opposite direction. I also have a 65 Scout and when I checked on that truck the wheels rotate in the opposite direction. The 63 has a powrlok but the 65 is open. Also, the nut was definitely lose on the driver side, if the pin was sheared maybe there is still be enough friction to rotate the axle since there is almost no load? I was able to find the torque recommendation in the manual which was 140-160lb-ft.

 

[Greg R]

Time for some detective work. If it was my rig, I would look at these things:

I heard what sounded like a pin dropping in one of the cases.

1) remove the shifter boot and retainer cap. Verify the locating pin in the shifter tower that allows the gear shift to pivot properly for gear selection.

2) take off the axle nut in question, and verify the key is in place. In fact, it wouldn't hurt to do both sides so that when you reinstall the nuts, you'll know you'll have the right torque on them.

3) drain the lube from the differential and pull the cover. It might need a good cleaning anyway; and would be a good time to eliminate any gearing/condition questions.

This is all easy stuff, much of it is done during normal service so you won't be out for any special skill or tools.

 

[mpanzar]

So I was finally able to pull the hubs/axles and somethings definitely not right! The pictures do a better job explaining but I think the left side wheel bearing was installed to far up the shaft ultimately leaving little engagement for the spline connection. The spline looks a little torn up on the very edge compared to the other. I also noticed that the tapered section (not the taper itself) is longer on one than the other. There was more that the allowable play in the axles (and no shims). Lastly the left side hub came of by hand.

 

[Robert Kenney]

I see what your problem is.
On these IH ra Dana axles, the id of the bearing itself is intended to seat on the tapered section of the axle not on the straight section. The inner race has a taper on the id that matched the shaft. I hope the bearing is simply wrong and that the po did not machine the tapper off the axle to fit a straight bore bearing.
I would not worry about the spline ends being a little damaged. They insert a long way into the spider gears and so long as the gear mating splines are ok it will be ok to use the shafts.

You should remove the cover and have a look at everything before spending any money on that axle.

I think you said you had a d27?

Bearing kit: http://www.IHPartsAmerica.com/store/d27-tabrg-kit.html
You can see a t on the bearing cone which indicates the taper.

Spider gear kit: http://www.IHPartsAmerica.com/store/nos-583755c91.html

 

[mpanzar]

It is a Dana 27. I am a little concerned with the condition of the axle and id bearing seat. When I pulled the axle it was pretty much a pile of parts just slopping around so the everything is pretty marred up. I'm less worried about the id seat since I can knock the high spots off and use some retaining compound if necessary. I am worried about the potential stress risers on the axle.

 

[mpanzar]

After further investigation I noticed one of the thrust shoes is missing on the left side as well.

 

[Robert Kenney]

I'm less worried about the id seat since I can knock the high spots off and use some retaining compound if necessary.

I might be reading your post wrong, so correct me if so.

That is guaranteed to fail if the taper is not utilized as intended. And not the way the bearings were designed to be installed. The bearing, bearing retainer and taper hold the shafts in the axle. Otherwise the axle will slide out through the bearing just as it did.

 

[mpanzar]

I agree with you about the taper. I was referring to the the interface between the cup and housing being marred up, not the cone and axle.

 

[Robert Kenney]

Thanks for clearing that. As I was reading it, I thought you might be referring to the housing bore...

On another item, where the one bearing is now on the flat of the shaft, a seal is supposed to ride. The can see the second smaller bore inboard of the bearing cup bore. Smoothing that area is good two fold. One as you say to reduce stress risers and second to extend the seal life.

 

[mpanzar]

Thanks, that makes sense, I would have never considered the life of the seal.

How critical are the thrust blocks? I have one of the two, although its in rough shape and I can see where the pin broke. I checked the carrier for the remains but I didn't find anything. I'm considering machining one if I cant purchase replacements. I am also curious how important they really are to the operation.

As for the axle(s) themselves, one of them hangs out 1/4" more than the other (without the thrust block installed) when just inserted as far back as possible. Is this normal? I am thinking its fine and will be compensated for when I install everything, and all torqued down?