As I recall split gears up till now have generally been the scourge of Bachmann’s GP7/9 and rarely of other GP/SD’s. Now my Spectrum doodlebug makes the characteristic knocking noise of a split gear. I studied the exploded view in order to find out how to take apart the power truck. It shows very clear the various parts of the power truck but I didn’t succeed in taking it apart. I don’t want to use force and risk breaking essential parts. Has anyone ever tried and succeeded in taking apart the doodlebugs power truck?
For the most part the split gear thing was centered around Life-Like Proto 1000/2000 locos, mostly geeps, some carbody units were involved as well. I also ran across it on some older Athearn blue box units. On one Athearn SD9 I had five of the six axle gears were split. A Proto2000 GP30 I bought had all four axle gears split. It would jump off the track within the first six inches of travel. I’ve experienced only one on a Bachmann diesel in twenty years, several on some small Bachmann steamers.
I looked at probably the same diagram as you and I see like many other models,the bottom cover comes off by placing a small flat head screw driver btwn. the truck and cover,the part that looks like a H on one side of the truck, and it should come off showing you the two axles with gears on them… You don’t have to remove the side frames to do that… This is N-SCALE correct???
My Bachmann HO RF-16 was making grinding noises and loosing power on grades and it turned out that a press fit drive shaft coupling had come loose and needed to be pressed back into place. That resolved all of my issues. Before you dissassemble the truck, double check that the drive shaft is tight and not slipping.
It’s a HO doodlebug and it is definitively a split gear. I recognize the knocking noise anytime having had my share of split gear GP’s. I have quite some experience with taking apart power trucks but this one baffles me.
Up to now that’s mainly been a problem with early HO P2K (Proto 2000) Life Like locomotives, not so much Bachman’s. With P2K it’s easy, Athearn trucks are essentially the same thing and they just snap together. Good thing too because Walthers supplies very little in parts support for these things.
Bachman has much better information and parts availability.
I’ve never had your particular truck apart, sorry. Usually if you look close there are some kind of tabs or covers that hold two halves of the trucks together. Maybe in some extreme cases, screws. These are usually shown if you have an “exploded” drawing of the assembly. Usually to get the wheels and axles out you pull the truck side frames off and snap off some kind of gear cover at the bottom of the truck.
If it’s N Bachman has an exploded drawing available on their web site. It looks like the truck sides just pull off, a bottom plate on the truck snaps off, and the wheels, axles, and gears can be pulled out. The gear tower gears appear to be held together with screws on the side that also serve as the axles for the tower gears.
If it’s HO, you have to dig a little deeper to get an exploded diagram.
http://cs.trains.com/mrr/f/88/t/216081/reply.aspx This is a collection of a bunch of manuals for various locomotives and other items that some kind soul has put together. Click on Bachman and Diesel Diagrams and way down at the bottom of the list is EMC Doodlebug 1 and 2, 2 is what you want.
The HO power truck looks a lot like the one in the Spectrum GE 44 tonner. The truck sides pull off to the side and there is a clip that holds the bottom of the truck together. Careful of the wheel power wipers that are attached to this part. Once out, the wheel and axle assemblies can then be pulled out of the gear tower.
Once you get the truck opened, check the gears for dirt particles first. I have seen a particle of dirt (ballast) get in between a gear tooth and make that same clicking noise.
I don’t think that noise is a split gear – we have 3 of them among our club members and all of them make that noise. It seems to be something that every Bachmann HO Doodlebug did.
That makes more sense to me than anything else. I had a similar thing with a Bachmann GP40. It was making a strange scraping sound. It was a small bit of wire. I never figured out exactly how that got in there! But taking it out stopped the racket.
I also have an HO Spectrum Doodlebug. Both of the axle gears split, and it was thumping and jumping because of it. The bottom of the truck is snapped onto the metal truck frame with a large latch on each side. The easiest way to remove it (with the engine flipped upside-down) is to grab the sideframes and pull up while your thumb pushes down on the cover. It should pop right off, and the axles will come up with it because of how the electrical pickups are assembled.
want to bet they will discover a cure for stupidity before this issue gets resolved? i got so fed up with the P2K gears cracking i gutted a bunch of the engines and made dummies out of them.
i had some that only had one bad gear. those got the teeth cut off of it and that results in an engine running like it has one traction motor cut out… 3 axles pulling and one going along for the ride.
i never had any spectrum diesels but i wonder if this chinese made stuff isn’t getting to be like water heaters. maybe there are only a couple of outfits that make them but they paint them different colors and put anybody’s label on them.
as for walthers being much help, just let me say they are a different company than the one WK started or the one Bruce ran for years. mustn’t have thoughts the king doesn’t like, you know.
Just don’t know why so many are/were so upset w/ the Proto “cracked gear” issues. It is such a simple fix, especially when Lifelike then Walthers set out complete axle, gear wheelsets. Took me longer to clean off the bench, set the foam cradle and grab the screwdriver than to pop the 2 covers and replace all 4 sets.
C’mon are were modelRR’s or really getting totally spoiled these days
I have managed to get gears from Athearn to replace the cracked ones but…
While not wishing to sound silly about, how do you best check for cracked gears? I have a sight problem (plus a few others with long and interesting names but I digress…)
Do you pick at the axle hole looking at it and check for movement? Bend the gear a particular way? I guess I could use a magnavisor but there must be an easier way and surely I have not cracked all my gears?
Are the drop ins actually for the older Protos or newer trucked versions? I hav a GP18 and a GP9 (in NAR markings)
I only have one of my Protos get a cracked gear. The others I just replaced with Athearn gears before ever putting them in service. The two I use at club shows have many hours of continuous run and it’s never happened again. There was no reason to gut the P2K locos, one time fix cures the cracked gear. If you only replaced the one gear that cracked each time, that could be a pain because eventually the other 3 will crack too. If you repalce all of them when one cracks, it never happens again. Of it it does, not for a long time, as my high mileage pair so far have had no repeat of the issue, with Athearn gears.
Pull the wheelset out of the truck and see if you can turn the wheels against the gear. Don’t force it. If the gear is cracked you’ll be able to turn the wheels easily.
Yes, there are problems with these parts which stem from dissimilar materials. It’s obvious that the tightness needed to hold the plastic gear onto the metal axle can cause problems, over time. It is interesting why the older Athearn Blue Box locomotives did not seem to have this problem and only certain models from certain manufacturers exhibit the problem. My guess is that there is a tolerance conflict between the hole in the plastic gear and the diameter of the metal axle shaft; or, it might be the material used in the plastic gear.
It’s to bad that the Athearn Blue Box kits are no longer available; but, I believe the parts ARE still available from Athearn. Replacement parts are available from NWSL, in fact I am awaiting these parts from them for my Walthers Doodle Bug, which has this very problem.
I have had some older Athearn’s that had that problem including a 70’s era PA with metal side frames. It didn’t make a clicking sound but actually made a clunk-clunk-clunk-clunk sound like a flat spotted wheel. The problem on the Proto model that were affected as I understand it was caused by a bad batch of gears in which the axle hole in the gear was too small.
See if there are traction tires, if so maybe one of them is deformed. I’ve had traction tires make a thud/thud/thud quick sound before and had to replace them. Plastic gears normally make a clicking type sound.