Bummer of a night...

[fogtender]

Well just about got the old Imp back together, had a dickins of a time getting the mirror and timing light just right to set the timing, last thing to do after everything else was to change the oil in the rear end before I put the tracks back on.

Started the engine up and ran it in gear the first time after having the tracks off to stir up the oil and the whole machine/driveline shuddered. Went though the shift pattern and in first on the rear, it runs smoothly then in second and third it shudders for a bit then smoothes out. I ran it for about five min's to stir the oil up good and drained it out. Looked like silver metal flake paint. The magnet drain plug didn't have too much on it, so I figure that it may be aluminum from something. Any clues on what is nonmagnetic in there?

When it was running, pulled the left brake handle and couldn't get the sprocket to stop completely, it did slow down, so I figure that something is binding the planitary system and not allowing it to spin freely on one side or the other. Was by myself and couldn't check the right side to see if it stopped, but the left one sped up when I pulled the right one...and vice versa....

It has between a thousand to twelve hundred miles on it since the last oil change, when I did it then it was really clean oil.

Anyway, will start to pull it out tomorrow, any thoughts what it could be? Went thought the manual and read up on it, appears to be a pretty simple transmission to work on "Once" you get it out... Worked on a lot worse!

It was suppose to have been rebuilt in Fairbanks before I bought it a few years ago. The company that rebuilt it is suppose to be pretty good at it, so I will find out shortly... Seems that the guy that had owned it, tore up the rear end trying to pull something in reverse and the reverse system design is suppost to be a bit weak.

Anyway, got the new backup spotlight mounted on the rear roof above the back door, backup mirror, tail lights (never had them, uses a yellow rotating beacon, still), CB, new springs, axles reinforced, greased all the bearing with new seals and a couple of marginal wheel bearings replaced, tuned up the engine and changed oil, installed a new tach. with the other gauges I changed out earlier that all have interior lights in them now so I can see them instead of the little dash light that shines down on them, and a whole bunch of other little stuff, but didn't do the trans. til last because it seemed to be running fine.... next time it will be first!
Still haven't repainted though, will be a summer job...

 

[MNoutdoors RIP]

Well just about got the old Imp back together, had a dickins of a time getting the mirror and timing light just right to set the timing, last thing to do after everything else was to change the oil in the rear end before I put the tracks back on.

Started the engine up and ran it in gear the first time after having the tracks off to stir up the oil and the whole machine/driveline shuddered. Went though the shift pattern and in first on the rear, it runs smoothly then in second and third it shudders for a bit then smoothes out. I ran it for about five min's to stir the oil up good and drained it out. Looked like silver metal flake paint. The magnet drain plug didn't have too much on it, so I figure that it may be aluminum from something. Any clues on what is nonmagnetic in there?

When it was running, pulled the left brake handle and couldn't get the sprocket to stop completely, it did slow down, so I figure that something is binding the planitary system and not allowing it to spin freely on one side or the other. Was by myself and couldn't check the right side to see if it stopped, but the left one sped up when I pulled the right one...and vice versa....

It has between a thousand to twelve hundred miles on it since the last oil change, when I did it then it was really clean oil.

Anyway, will start to pull it out tomorrow, any thoughts what it could be? Went thought the manual and read up on it, appears to be a pretty simple transmission to work on "Once" you get it out... Worked on a lot worse!

It was suppose to have been rebuilt in Fairbanks before I bought it a few years ago. The company that rebuilt it is suppose to be pretty good at it, so I will find out shortly... Seems that the guy that had owned it, tore up the rear end trying to pull something in reverse and the reverse system design is suppost to be a bit weak.

Anyway, got the new backup spotlight mounted on the rear roof above the back door, backup mirror, tail lights (never had them, uses a yellow rotating beacon, still), CB, new springs, axles reinforced, greased all the bearing with new seals and a couple of marginal wheel bearings replaced, tuned up the engine and changed oil, installed a new tach. with the other gauges I changed out earlier that all have interior lights in them now so I can see them instead of the little dash light that shines down on them, and a whole bunch of other little stuff, but didn't do the trans. til last because it seemed to be running fine.... next time it will be first!
Still haven't repainted though, will be a summer job...

On controlled differentials they are not suppose to stop completely on either side only slow down. one side will go to 1/3 speed and the other to 2/3 speed thus you get your turn. the only time you get both to stop is if you pull both levers

 

[pixie]

Sorry to hear that, Mark. I hope you get the gears fixed quickly and without much pain or expense.

 

[fogtender]

On controlled differentials they are not suppose to stop completely on either side only slow down. one side will go to 1/3 speed and the other to 2/3 speed thus you get your turn. the only time you get both to stop is if you pull both levers

Well that makes me feel better, kinda like getting "Pushed" off a tall building verses "Jumping"... same results though, got to find out what the metal dust and noise is coming from.

Thanks though!

 

[fogtender]

Sorry to hear that, Mark. I hope you get the gears fixed quickly and without much pain or expense.

Thanks,

Well I would rather find the problem in the shop when it is up on jack stands than about fourty mile out on the trail....

 

[mtncrawler]

Fogtender, I don't think you have a problem from what you describe. I think the metalic particles you are seeing are from the steering bands wearing on the drums. The band material usually has brass woven into it which glitters in the drain oil. This is normal on my A-Sprytes with the OC-4 drive when I change oil too. The transmission and the steering differential boxes flow oil between each other so either drain plug will show the same glitter. Like you I run the machine and get the drive warm as to get all the contaminates in suspension before draining both bottom plugs. Then I fill through the rear top plug of the differential and let it flow through into the transmission until it spills out of the level plug hole on the left side of the transmission. If the fresh oil is cold it may be necessary to let it settle for awhile and let it run out of the level hole to avoid overfilling. Excuse me for outlining this process if you're already familiar with it, maybe someone else will gain. There are alot of different opinions on what oil to run in these OC-4's. Some guys run aviation motor oil because the book calls for non-detergent motor oil. I've heard of using John Deere 1000 fluid and other stuff too. Myself I use 10W40 motor oil. It's cheap and easy to get and it's probably of a much higher quality than the 40WT non-detergent they had back in 1950. And I change it at least twice a season to flush out all that bad stuff you were looking at earlier. Frequent oil changes, in my opinion, is the best thing you can do for that steering differential transmission.

 

[fogtender]

Fogtender, I don't think you have a problem from what you describe. I think the metalic particles you are seeing are from the steering bands wearing on the drums. The band material usually has brass woven into it which glitters in the drain oil. This is normal on my A-Sprytes with the OC-4 drive when I change oil too. The transmission and the steering differential boxes flow oil between each other so either drain plug will show the same glitter. Like you I run the machine and get the drive warm as to get all the contaminates in suspension before draining both bottom plugs. Then I fill through the rear top plug of the differential and let it flow through into the transmission until it spills out of the level plug hole on the left side of the transmission. If the fresh oil is cold it may be necessary to let it settle for awhile and let it run out of the level hole to avoid overfilling. Excuse me for outlining this process if you're already familiar with it, maybe someone else will gain. There are alot of different opinions on what oil to run in these OC-4's. Some guys run aviation motor oil because the book calls for non-detergent motor oil. I've heard of using John Deere 1000 fluid and other stuff too. Myself I use 10W40 motor oil. It's cheap and easy to get and it's probably of a much higher quality than the 40WT non-detergent they had back in 1950. And I change it at least twice a season to flush out all that bad stuff you were looking at earlier. Frequent oil changes, in my opinion, is the best thing you can do for that steering differential transmission.

Well I would hope that is the case, but I get a Shuddering when I first let out the clutch as it starts out, then settles down. I don't recall seeing much that the magnet wouldn't attract and it was strange to see the flakes with nothing on the magnet... It was a silver though and not brass colored, maybe the oil changed the effects of the light. Was getting late and I was tired, didn't do anything with it today. Tomorrow I was going to dump the oil into a pan (from the drain pan that drains down into a tank) and take a second look at the oil. Was going to at least lower the rear of the Rear end and take the cover off to inspect at least, if for no other reason to make me feel better if nothing is amiss.. If it is, I am just that much closer to getting it done.

Has anyone else run the Imp's C-4 on jack stands with the tracks off and noticed any shaking/shuddering from them on engaging? Wouldn't think that was normal, would rather error on having the problems in the shop that fourty miles downt the trail...long walk back...

 

[Alaska Snow Cat]

I would look at any drive shafts and u-joints closely as the cause of shuddering. A dry u-joint may appear to be "tight" but will cause vibration problems.

 

[roughwoods]

Mark when I ran my imp on jack stands, there was no shuddering or anything. I ran it thru all the gears ,but I did not run it at high rpms.And as you know I had no metalic flakes.Sure hope you get it fixed.Let me know if you need help.

 

[Bulldog1401]

I would look at any drive shafts and u-joints closely as the cause of shuddering. A dry u-joint may appear to be "tight" but will cause vibration problems.

And also check for oil on the clutch disk. Is there any chance some got spilled there?

 

[Bulldog1401]

There are alot of different opinions on what oil to run in these OC-4's. Some guys run aviation motor oil because the book calls for non-detergent motor oil. I've heard of using John Deere 1000 fluid and other stuff too. Myself I use 10W40 motor oil. It's cheap and easy to get and it's probably of a much higher quality than the 40WT non-detergent they had back in 1950.

Do you have crisp turns with the 10w40? No glazed bands?

 

[fogtender]

Checked out the u-joints and they are well greased and tight. No oil on the clutch that I know of, but the shimmy could come from there too, the shimmy felt like it was coming from the rear, almost like a chatter, could be the clutch, but it pulls really well. Will start tomorrow morning with a fresh start and go though everything from the front to the rear and recheck the oil to see what all it there. Going to pull the rear cover off to see inside to make sure that there is no real metal wear and check the bands... Should know by tomorrow night...

Thanks for the thoughts!

 

[fogtender]

Mark when I ran my imp on jack stands, there was no shuddering or anything. I ran it thru all the gears ,but I did not run it at high rpms.And as you know I had no metalic flakes.Sure hope you get it fixed.Let me know if you need help.

Thanks, shouldn't need much but a really big hammer...

I put a lot use on it since the last oil change with all the freight we were hauling out to the cabin, dragging moose and all, maybe it is just a few simple issues. Will know shortly...

 

[mtncrawler]

Do you have crisp turns with the 10w40? No glazed bands?

A-Sprytes have alot more track on the ground than 1404's so no, it won't turn with an Imp. But it steers well, and I've been using 10-40 for over a decade so I don't think glazing is a problem.

 

[Bulldog1401]

A-Sprytes have alot more track on the ground than 1404's so no, it won't turn with an Imp. But it steers well, and I've been using 10-40 for over a decade so I don't think glazing is a problem.

Does it stop aggressively, or roll to a stop? I am interested in using the 10w40 if it does not take away from performance. Thanks.

 

[fogtender]

Well dropped the Rear axle down and pulled the cover.

After giving it a bit of thought since I was getting the "Chatter" in the rear when I put it in gear, and the fact that I was up late and getting tired when I drained the metal flake oil came out...

I dropped the rear down and took off the cover to see what kind of "damage" to expect. Appears that there is none. One thing I did find is that when you do change the oil, there is a "Pool" of it that won't drain out unless you have the unit pointed downhill fairly well. When I pulled the cover off, after draining the oil out, there was 1/2" deep of the sludge in the bottom that could have been there for some time.

There was no metal in the oil that a magnet would pick up, so I am assuming that the metal flakes are coming from the bands, which do have some kind of silver metal weave in them...

After thinking about the shimmy that I had, it may be that when I had the rear end blocked up in the middle, the axle assembly was allowed to rock when I put it in gear since the axle floats on the centerline of the machine...

Anyway, cleaned out the scum, added some positve adjustments to the brake bands to give more adjustment outside while I was in there and put it back together....

Thanks for all you suggestions!!!

 

[pixie]

That's good news

I hope that's all it was.

Great picture of the rear The man I bought my Imp from had 8x10 glossies of the rear end rebuild. He was fond of them and didn't include them in the sale

 

[snowbird]

My Bombardier differential looks much like yours and my "consultant", Boggie, suggested I use HyTran fluid like I used in my farm tractors (John Deere) in a former life. I'm not sure what the advantages are, but Boggie has tons of experience.

 

[fogtender]

My Bombardier differential looks much like yours and my "consultant", Boggie, suggested I use HyTran fluid like I used in my farm tractors (John Deere) in a former life. I'm not sure what the advantages are, but Boggie has tons of experience.

Going to try Shell Aero 50W 100, no detergent in it and should still be low enough for the cold weather. Have to go to Fairbanks to pick some up. I had a Chevon hyd oil in it before, but didn't like the sludge that was forming from it in the pan, seemed to be breaking down someone. Any suggestions or opinions?

 

[Bobcat]

While in Squarebanks, howsabout a picture or two of the FT Wainwright snowcat yard and maybe one of the Snowtrain just east of it?

 

[fogtender]

While in Squarebanks, howsabout a picture or two of the FT Wainwright snowcat yard and maybe one of the Snowtrain just east of it?

Won't be able to do that tonite, but maybe in the next week or so... Days are still short and by the time I get there after four PM, it will be too dark...

By the way, when headed into Nenana at eight AM this morning, the Northern Lights were still out and looked pretty neat!

 

[Bobcat]

One of the most amazing things I've ever seen was the lights above the SE edge of the Brooks range. I was on top of Burnt Mountain, half way between Ft Yuck and Arctic Village. It was absolutely pitch black but the lights appeared as if they were only about 50ft above your head and extremely bright, yet you still couldn't see the hand in front of your face. Even if I could have taken a picture, no picture could do it justice. The combination of the colors, movement, and perception that it's just above your reach can not be duplicated with any media.

Here's a little snippet about what I may have been doing on Burnt Mt...

http://www.juneauempire.com/stories/071601/sta_Nuclear.shtml

 

[IMP]

Fogtender, I saw some AeroShell 100 50W oil at the Fairbanks Sams Club the other day for $30/ case. I plan to use the same in my IMP transaxle. Also I would like to ask you to post some photos of the IMP frame structure where your transaxle bolts up to the pivot point in front and rear. Someone did a real hack job modifying the frame supports and mounting area of the front transaxle pivot point on my IMP. I would like to replace my support and was looking for ideas on what would be the best way to rebuild it. I just read your description of how you strengthened your boggie axle by pounding a pipe inside your 2" square tube. My 2" square tube was strengthened by replacing it with SOLID 2" square stock!! A bit extreme but effective. Just thought you might find that interesting.

 

[fogtender]

Fogtender, I saw some AeroShell 100 50W oil at the Fairbanks Sams Club the other day for $30/ case. I plan to use the same in my IMP transaxle. Also I would like to ask you to post some photos of the IMP frame structure where your transaxle bolts up to the pivot point in front and rear. Someone did a real hack job modifying the frame supports and mounting area of the front transaxle pivot point on my IMP. I would like to replace my support and was looking for ideas on what would be the best way to rebuild it. I just read your description of how you strengthened your boggie axle by pounding a pipe inside your 2" square tube. My 2" square tube was strengthened by replacing it with SOLID 2" square stock!! A bit extreme but effective. Just thought you might find that interesting.

I will post some photos of the Pivot points tomorrow when I get back out to the shop.

Bought some of the Aeroshell tonite at Sams Club, it was $43(+change) a case of 12 quarts. Should be getting the tracks on tomorrow. Was helping Roughwoods get his Imp timed today with a new distributor, they sure didn't make it easy to get to the timing marks on them the way they are mounted... On his, he had to take the belt off the alternator and lay it down so the timing light could hit it. His is a 60's model and the engine is a tad different than my 70's version, which was even harder to get to the timing marks....

I chose the round pipe so there was an area that allowed it to flex just enough not to be so stiff that it would break, but stiff enough to keep it from cracking. The ends are bolted instead of welded, that allows a small about of movement in the "Flexing", had I welded it, it would be again, too stiff. In the event that the outside axle did start to crack, I figured the bolt would hold the axle in place until I could get back to someplace to fix it... "We will see" said the Blind Man....

 

[IMP]

I see a side shot of your skid plate... very good idea! can you get some photos of that too. My IMP has a crude built skid plate protecting the drive line where it goes into the transaxle only. My transaxle case is so scared up on the bottom the drain plug is ground down smooth and unremovable. The case also had a crack in it that I welded but as of yet is untested. Im just finishing up building my tracks and waiting for the return of my new reconditioned drive sprockets

 

[fogtender]

I see a side shot of your skid plate... very good idea! can you get some photos of that too. My IMP has a crude built skid plate protecting the drive line where it goes into the transaxle only. My transaxle case is so scared up on the bottom the drain plug is ground down smooth and unremovable. The case also had a crack in it that I welded but as of yet is untested. Im just finishing up building my tracks and waiting for the return of my new reconditioned drive sprockets

For the time being, I took the skid off. The route that I use to the cabin is pretty good now and I don't have any really rough stuff to climb over that I would be worried about hitting the axle on. In the event that I had some kind of problems and had to do a field repair, the skid would make the job a lot harder to preform.

It lowered the rear clearance about an inch, which when breaking a new trail, it packed the snow down so well it looked like I left a groomed trail, which was nice for follow up trips on a faster snowmachines. Whomever built it, did a really nice job of setting it up. It bolted to the Pintle hitch in the back, came down and two arm came up and bolted to the rear pillow bearings and then had two hangers welded off the front frame at the end of the tunnel.

I don't have too many photos of the skid plate, but I have one at the cabin that shows how it comes down from the rear pintle hitch, not very good, but does show how it covered the axle from the rear...

Unlike some snowcats (Most! ) that sink so deep that snow rolls up off the inside of the tracks and makes two high ridges in the trail so badly, you have to pull a trail drag or even snowmachines can't follow you the next day without tipping over.... The wide track Imp doesn't sink that much on snow to start with, and with the lower ground clearace, leaves a pretty nice trail, but the skid plate did an even better job of leaving a groomed trail behind.....

 

[fogtender]

I see a side shot of your skid plate... very good idea! can you get some photos of that too. My IMP has a crude built skid plate protecting the drive line where it goes into the transaxle only. My transaxle case is so scared up on the bottom the drain plug is ground down smooth and unremovable. The case also had a crack in it that I welded but as of yet is untested. Im just finishing up building my tracks and waiting for the return of my new reconditioned drive sprockets

Got any photos? If you are in Fairbanks, and have the time, maybe you could show it to me.

 

[IMP]

That would be great! I live at 5 mile Chena Hot Springs road. At this time my IMP is at my home inside a large shop with heat, on jack stands, track and transaxle off. If you will be in Fairbanks and have an hour or two to spare, come on over, Just let me know when. I will PM you my tel. #.