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kgrant

My 1998 Big Boss 6x6 Project

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Hello, great forum here!

 

I bought a non running 1998 Big Boss 500 6x6. The previous owners had done quite a bit of work to it. It has a new carburator, fuel pump, starter, adjusted the valves, new mid sprockets and chain. But they said it wouldn't run.

 

When I got it home I did get it to run, though not very well. It doesn't want to idle and there is a very loud knocking. I didn't run it very long. Hopefully it's just the clutch knocking. It has 4000 miles on the odometer. I popped off the valve cover and the cam looks ok, (it's not flat!) I haven't measured it yet. I still need to check compression.

 

There's no oil in the gearbox, found a crack in the case behind the output shaft. Looks like a mounting point?

 

I think I'll try and find a case half. I should probably tear apart the gear box first, it might be in bad shape inside. Who knows how long it was ran without oil. It does shift between all gears.

 

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The rest of it is in fair condition, normal wear and tear for 4000 miles.

 

Sorry I don't have any pictures of it other than the cracks.

 

I should probably make sure the motor is good before I put money into the gearbox.

 

Any tips on things to look for would be appreciated!

 

Thank you

 

 

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Wow that sucks.  But yes overall a new side case will be in order. Not a bad deal other then the labor sore of it.  New gasket kit complete kit. Might as well bc you never know what you will need going down the road.

I like to take a big piece of cardboard and stick the bolts in the cardboard and mark down where it came from with a sharpie, keeps it easy to keep track. 

Pressure wash the shit out of everything before you tear into it so it’s somewhat clean. 

Keep us posted and take lots of pics as you go. 

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I found a right side case on eBay for $50 and bought it. There are tons of left side cases on eBay, this was the only right side listed. Maybe this is a common problem?

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You would have to research that and see how many complaints or problems came up.  

$50 bucks is a great price.  Just take your time and be patient.  Maybe do some YouTube searches and see what comes up. 

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I remember busting the case on a 98 Xplorer 300 when the chain broke! Seems like it was just the right side.

Hopefully all I'll need is the right side. I haven't pulled the gearbox out yet. Might have jumped the gun on buying it! But I didn't want to miss out on being able to buy it.

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Compression is 75 psi, spec says 50-90 is normal. Valve clearance all measure around .006", spec I found is .0024".

Started taking the gearbox out. Looks like I'll need to pull off the primary clutch so I'll need to get a puller. Might try the water trick if I can get it tilted up far enough.

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I thought it would have higher compression too. I read that the auto decompression is why they read low.

Clutch came off with no issues. The bolt out of my pitman arm puller was the right size. Used the handyman jack and picked up as high as I could without the jack slipping out, filled hole with water, ran the bolt in and the clutch popped right off! My first time using the "water trick", I'm sold!

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Gearbox come out without any issues.

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I think this sprocket was why the case broke...

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Now I need to clean everything up and work on the motor while I wait for parts.

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Makin work of that. Nice stuff, now the wait for the pets starts.  Hate that part. 

Well it looks like your doing great.  Keep us posted. 

Good luck. 

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I have all the sprockets and chains for the rear to replace as well. I think I'll hold off on those until I get the gearbox fixed.

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Sweet project!

Thanks!

Makin work of that. Nice stuff, now the wait for the pets starts.  Hate that part. 
Well it looks like your doing great.  Keep us posted. 
Good luck. 


Still plenty to do on this project. Trying to get motivated to clean everything up.

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Post #6, I'm wrong on the valve clearance specification. The spec is .006", not .0024". Too late to edit my post...

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Since I don't know  just how the clutch is removed , I  can  only comment  on the  water trick.  It sounds like the same trick  used in the automotive trade for removing  bushings in blind holes (  mainly  the pilot bushing in  the flywheel on cars with standard trannies) . Instead of water,  use  grease. no worry  about  it spilling out of the hole no matter what angle it is on.

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Since I don't know  just how the clutch is removed , I  can  only comment  on the  water trick.  It sounds like the same trick  used in the automotive trade for removing  bushings in blind holes (  mainly  the pilot bushing in  the flywheel on cars with standard trannies) . Instead of water,  use  grease. no worry  about  it spilling out of the hole no matter what angle it is on.


Yes, this is the same trick. You can put anything in the hole that won't compress. I've read where people have even used bread.

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I went through the carburator today and got her running.

Doesn't sound very healthy! I listened all over the engine with a screwdriver to my ear and couldn't pinpoint the noise.

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Well, good bad news and good news.

The bad; I was idling the engine tuning the carburator, and it seized up! Couldn't budge it with the starter or recoil. Pulled the spark plug and recoil cover and was able to break the engine free using the flywheel. Loud squealing from the cylinder. Put oil in the cylinder and turned it over a dozen times. Put the recoil cover back on, and used the electric start and turned it over a bunch more.

Then I decided to drain the oil. Normal 2 quarts from the tank. Then I pulled the oil filter, it was bone dry! Pulled the crank case plug, about 4 drops came out! WTF! There's normally about a cup in the crank case.

So I'm thinking man, I guess the oil pump failed?

The good; Started looking at a drawing of the oil system and compared it to mine, and found the hoses on the oil pump were backwards! The previous owner had three oil tank off, guess they goofed up on the hoses. Swapped the hoses, started it up and the motor sounds a little better, but now there's lots of blow by because it's getting oil, lol. I'm glad I found the reason why it wasn't getting oil before I took the oil pump apart.

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Ran it a bunch more, no smoke from the exhaust. Just the crankcase vent.

So I guess a minimum I'm going to need rings.

This thing is turning into more of a project than I anticipated!

Looks like I can remove the cylinder without taking the engine out.

I know, I should go through the whole engine. The plan for this is to take it to the cabin, where it might get 10 miles a year put on it. I'll risk the rest of the engine as long as there's no big peices that come out when I change the oil again.

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Gear case parts came in! I read through the service manual a few times and dove into it. Went really smooth! Ready for install, probably be tomorrow's project.

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Awesome pics brother.  Doing great, keep up the good work.   

Thanks! I had time before work and was able to get the gearbox in the frame.

8e6f2352eb74578e2c82cd01412c29f9.jpg
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