Need Help, D4600 Flywheel being a pain in the rear!

Hey Farmall,

I am not an expert at all, but I'll throw my self out there so others can have fun. I would heat up the fly wheel, with a rose bud. Sounds like things weren't lined up just right, maybe off a hole or two. Bolt seized up. After heating fly wheel it sould come out. Use never seize on all the bolts, I use it on most stuff. Try rotating the flywheel until you find the right spot. Not familiar with the 4600, if it only goes on in one spot, maybe it needs to be flipped the other way. Trust me, I am learning the hard way when taking things apart, to mark everything, with a paint marker pen, to remember the exact spot to line 'em up again.-glen

Most any engine being Caterpillar, Farmall, Chevy or whatever will have a mark stamped into it and a bolt pattern that will only allow it to go on One Way. This is so the Timing marks on the flywheel will appear in the right spot on the crank (this also affects the balance of the crank & flywheel). Usually there will be one or more bolts offset so they won't go in unless it's in the right spot. You may have the flywheel on wrong and one of the bolts is cross threaded. You can check this by lining up the TDC mark on the flywheel with the timing hole in the bell housing and making sure the number one (front) piston is at top dead center.

A helpful hint: while you have the flywheel off, take some white spray paint and paint the spot on the backside of the flywheel where the timing marks are. You'll thank yourself for doing that if you need to time the engine.

If I remember correctly, Cat used a slightly smaller tap (Class 3B I think) when they tapped the holes in the crankshaft for a precision fit. Is the offending bolt all the way in or is it just part way in? Could it be cross threaded? I think I'd try a 1/2" impact wrench on it first at low power and maybe increase the power by stages.

If that doesn't work. .find a nut to fit over the bolt head and plug weld it on. Let it cool and the bolt should shrink a bit and come out easier.

The D3400, 4400 & 4600 crankshafts don't use an indexing bolt pattern and depend on indicator marks, usually chiesel to indicate alignment. The fine threads are easy to cross thread, even more so with a correcting tap.
That's a real challenge to correct and the odds are not good.

Mounting the flywheel onto a couple of removable studs is the best way to avoid the problem.

Old Magnet, when using the stud method, do you leave them in there or are they just there temporarily while the other bolts are fitted? I'm going to pull my D3400 flywheel to clean all the mouse crud out and don't want to feel the pain that others have (thanks for blazing the trail you guys!)
Cheers,
Neil.

Your assumption is correct. Just temporary guide.

Thanks guys for the advice, I used a little heat to get the bolt out of the flywheel, then made some guide pins with some new bolts and with in a half hour I had it on and tight and the clutch bolted back up. Now tomorrow, hopefully the engine will go back in. Any advice on this procedure will be much appreciated, I am sure it won't go in as easy as it came out. Thanks!👍

The "tractor gods" were smiling on that recovery.........

Well, I got my D3400 flywheel off today - boy those six bolts are a close fit! One of them has the threads flattened a bit. Of course I didn't mark which holes they came out of so I'm going to have to study it closely with a magnifying glass to figure out which hole the dodgy bolt came from.
Would you guys recommend running a tap up the hole in the crank flange and/or a die up the bolt (or just buy a new bolt)? I'd like to make it as good, if not better.

I think the ring gear is so rusted out on one side that the pony pinion would quickly chop the remaining part of the tooth off. Given that, what's your recommendation for a replacement ring gear? Are second-hand spares ok or am I better off just contacting Cat for a new one? I'll see if I can upload a picture.

Cheers,
Neil.