Continuing Proto 2000 gear problems

Discussion in 'HO Diesel Locomotives General' started by meteor910, Apr 18, 2011.

  1. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    Is anyone else still having problems with cracked gears on Proto 2000 units? (pre-Walthers)

    They certainly look good, but their good looks are exceded only by the crummy quality of the gears in their Chinese drives. The motors are not the best, either.

    I took out my P2K GP20, in EMD demo colors as EMD 5628 (NEAT looking locomotive), tonight to run it on the point with my Frisco RS2m SLSF 553 to make an interesting combo on a 15 car freight. The Frisco did try out the demo GP20's in the early 1960's.

    Everything ran fine for about two-three minutes, then all of a sudden it started ..... "ca-thunk ca-thunk ca-thunk", the sound of a cracked axle gear, a demon in many P2K units, usually geeps. It ran that way for about another minute, then it bound up and all came to a quick stop. Turns out it was the rear axle in the rear truck.

    I complained about this problem to Walthers a couple of years back, shortly after they bought Life-Like P2K, and they kindly sent me several replacement wheel sets. But, it's a pain to do the repair.

    I now have five P2K locomotives suffering from this problem. They all run, but with varying degrees of "ca-thunk", except for the GP20 now. They are:

    GP20, EMD 5628
    BL2, Monon 36 (was the worst until the GP20 locked up)
    FB1, GM&O B-9
    GP9, PRR 7160
    GP30, SLSF 900 (!)

    Yeah, yeah, I know - the Frisco never had any GP30's. Years ago, when the P2K GP30's were first released, I bought a Nickel Plate unit on sale because it was NKP 900, in black, with yellow stripes. I kept the NKP stripes, but changed the lettering to Frisco. I thought that would really be cool - a Frisco GP30 - but it looks silly. The NKP stripes are all wrong for a Frisco unit. It also is non d/b, but I put a fan up top to make it look like it was d/b, though there are no grills in the side d/b housings. Like I said - silly. My plan is to scrap it for parts.

    Does anyone else have a bunch of lame P2K's in your fleet? Thank goodness this problem has rarely surfaced on their E-units. My E6, E7's and E8's all run like Swiss watches.

    Last edited by a moderator: Apr 18, 2011
  2. Iantha_Branch

    Iantha_Branch Member

    I went to buy a KCS GP30 at a swap meet and it had the same problem.
  3. friscomike

    friscomike Administrator Staff Member Administrator Supporter


    Last month I put a brand new Alco FA FB FA set on the Texas Western, and they lasted one operating session before the clicking started. They are on my workbench to replace the gears with Athearn gears. Really ticks me off...

  4. renapper (Richard Napper RIP 3/8/2013)

    renapper (Richard Napper RIP 3/8/2013) Passed away March 8, 2013

    I bought 20 Proto 2000 E-8As and E7As. All of them had an Athearn Motor and drive system. I have not had any problem with broken gears in any of them.
  5. gstout

    gstout Member Supporter

    This problem does occur with the E-units. I have a P2K E9 that started doing the same thing, and before I was enlightened as to the cause and repair I gave up and de-powered it, making it a dummy (if you do this, be sure to remove the humongous cast metal weight). Had the same difficulty with a GP7, but by that time I knew the drill. However, be aware that Athearn has apparently recently raised the price on the replacement gears, so the fix will be a bit more expensive than before.

  6. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    The Athearn gears will work as replacements. I bought a large quantity to have as spares. Nearly every one of my original P2K (before Walthers' purchase of Lifelike) have had axle gears crack. I believe it is caused by a combination of tight fit on the axle shafts and the type of (non plastic-compatible) gear lube used.
  7. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    I'm a bit concerned. I tried for a quick fix on the GP20 last night. I opened up the drive train on the rear truck on the GP20 from the bottom - without taking the body off the chassis, etc. I slipped out the "bad" wheel & axle set and replaced it with a new one. I could see no crack in the gear on the axle of the wheel set I took out. I popped the truck bottom cover back on and set the GP20 down on the track to roll back into service. The results: ca-thunk ca-thunk jammed. Now what? I guess the problem could be in one of the other gears in the drive train, but all my prior experience with this problem has been with the axle gear.

    So much for quick fix attempts!

    Keith - Do you have the Athearn part number for the new wheel sets? I assume it comes with the wheels, axle, gear, and bearings all together? I only have three new Walthers wheel sets left, one now in the GP20, so I'll need more if I want all five of these lame P2K beasts rolling again.

    Last edited by a moderator: Apr 19, 2011
  8. friscomike

    friscomike Administrator Staff Member Administrator Supporter


    The Athearn numbers are Loco Drive Axle Gear SD 40-2, ATH 60024, 6 per pack. Mine were priced at $4.95, but don't know when they were purchased.

  9. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    Mike and others ..... who do you order Athearn parts from?

  10. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    Well, the bad P2K wheel set gear saga continues ......

    As I described in my earlier posting, I attempted a quick fix on the "ca-thunking" GP20 last night by simply taking the bottom cover off the rear truck and substituting another geared wheel set in place of the rear axle, rear truck. No dice, we still "ca-thunked" and it jammed up again.

    I got to thinking about it tonight during the bad storms we had here, armed with a stiff glass of adult beverage to get me through the evening weather trauma and, of course, to expand my mind. The replacement wheel set was one I had laying loose in my power truck parts box. It was not one of the three new wheel sets I have left of the four Walthers sent me. Those three were in a Walthers envelope - the one I selected last night was loose. Yes, you guessed it, the replacement I selected last night was a bad one that I had replaced a couple of years ago on the PRR GP9 with the fourth new one from Walthers. Last night, I replaced a bad wheel set with a bad wheel set! Go figure.

    When I installed a genuine new Walthers wheel set in the GP20 tonight, it stepped up and ran smoothly. Well sort of - now that the rear truck is running quietly, turns out there is also a minor ca-thunk coming from the front truck. Looks like it is the first axle. I'll run the GP20 as-is for a while before I decide to replace the bad wheel set as it's not real bad.

    In the meantime, I'm going to order some more replacement wheel sets! Maybe the thing to do is what Keith did - just re-wheel the entire locomotive.

    The GP20 is on the point again, with RS2m SLSF 553 trailing. Looks pretty good. I'll attach a couple of quick pics I took.


    Attached Files:

  11. gjslsffan

    gjslsffan Staff Member Staff Member

    Hi Ken,
    I used this # to call Athearn directly, and have been given great service every time. Never needed a part # either, just told them what I wanted. They even took a loco apart once to see that I got what was needed.
    email ( or telephone (310) 763-7140, ext. 122, Monday-Friday 8:00am-3:30 p.m. Pacific Time.
    Hope This helps,
    Tom Holley

    P.S. that 553 looks familiar:)
    Last edited by a moderator: Apr 19, 2011
  12. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    The Athearn part number for the gears is 60024. The original axle ends will fit into the Athearn gears.

    Ken, based on your description of the problem with the GP20, I suspected that the problem is some kind of foreign matter in the gear train of one truck. Remove the trucks from the frame and leave the worm gears at the top out. The trucks should roll freely. If one truck is binding or jammed, disassemble that truck to inspect the teeth of all the gears. In my experience, I have seen a piece of ballast, solder, tiny chunk of styrene, or wire insulation caught in the gears.

    The Athearn gears I bought came from ebay.

    (Note: I started typing this answer four hours ago and never hit Post Reply until a few minutes ago. I see Ken determined his problem but the advice is still good for other possible circumstances.)
    Last edited by a moderator: Apr 19, 2011
  13. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    I replaced both the axle wheelsets in the front truck of EMD demo GP20 5628 yesterday and now it runs smoothly without "ca-thunks". I am out of wheelsets now - more on the way. I'll replace the remaining last original wheelset in the rear truck when they arrive, and will "de-ca-thunk" (new word invented for HO Proto 2000 GP/FA/FB owners!) GP9 PRR 7160 as well.

    Next P2K GP problem is how to make their motors a bit more responsive. I think the answer is to repower them!

  14. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    P2K update - I spent some time late this afternoon tearing down my HO Proto 2000 EMD BL2, Monon 36. Yes, it's ugly as sin, but, hey, it's in Purdue University colors - old gold and black, so it looks pretty good. People have often said the EMD BL2 was so ugly it looked good. I agree.

    Anyway, this thing was my Number One P2K "ca-thunker", so I thought I would try to improve its level of performance. Thanks to a very good friend, who sent me an emergency supply of P2K axle gears, I had enough parts to completely regear each drive axle. I found EACH of the four original axle gears was cracked, one of them very badly. Yikes! I'm surprised it would even run (it would seize up suddenly now and then).

    While I had the BL2 apart, I changed out the poor P2K couplers for Kadee 153's, gave the drive train a cleaning and a bit of fresh lube, gave the crew some colored clothing, and gave a few other details some upgrades. I had previously detailed the body to a point that it looked real good, but today's fixes even improved it more. Lookin' really good now! Hail Purdue!

    I just put everything back together, and placed it back on the rails, on the point, leading P2k GP20 EMD 5628 (previously de-ca-thunked), and P2K GP9 PRR 7160 (still has a minor ca-thunk issue) on a 15-car train, and cautiously gave it some power. The BL2 runs smooth as silk now, no clunks. Great! Even the poor P2K motor seems to run smoother.

    Got to get some more of those axle gears ordered. This is renewing my faith that P2K GP's can be made to not only look great, but to run well.

  15. friscomike

    friscomike Administrator Staff Member Administrator Supporter

    And I thought you were going to say the ugly BL2 caused the GP20 and GP9 to start ca-thunking again... ~mike :eek:
  16. Sirfoldalot

    Sirfoldalot Supporter Supporter

    BL-2 = EMD's Edsel
  17. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    Be assured that most of the Proto 2000 locomotives run fine, though I do not like some of their motors. I am speaking of the pre-Walthers P2K's. Though the body shells of their locomotives were always terrific, or close to it, they seem to have used different sources for the drive/chassis. All of their motors are not the same. I have many that run great, but have a few that remind me of an old Athearn "Blue Box" - takes about 1000 volts to get it to move.

    Regarding the axle gear and collar, yes, they are pretty standard. The modern Athearn part looks to be indentical - I'd guess early on, P2K standardized on this proven system. Often truck side frames are compatible between different brands as well.

    P2K seemed to start having axle gear collar problems on their Alco FA/FB's (first run, GM&O for me. My SLSF units, second run, are all fine) and the first runs of their nice series of GP models (GP7, GP9, GP18 (2nd run), GP20, GP30). All of these that I have are, to some degree, "ca-thunkers". Also, the BL2 (second run, not the very early one). The BL2 was the worst, it barely would run. The others run OK but clunk, some not too bad, some louder.

    The wheel, axle and bearing assembly (2 per axle) are press fit into the geared plastic axle collar. They are accessable from the bottom of the truck, so you don't have to take the shell off of the model to change out the wheelset. (But you gotta be careful to protect the fine details on the shell, plus, don't get a fingerprint on the shell - P2K used a lot of gear lube grease (known as "peanut butter"!) that will leave a lovely fingerprint on your model if you aren't careful). To get the wheelset out, use a thin screwdriver to pop off the truck bottom plate, working carefully from each end. Then the wheelset can be removed and inspected. Take a look at it under a bright light and with magnification (I use my OptiVisor). The crack is very fine but usually runs clear across the left collar, through the gear, and across the right collar. As the wheel is turning under power, and the drive gear reaches the crack in the axle gear, the crack opens a bit under the thrust pressure and a "ca-thunk" occurs. Sometimes it is so bad the wheel locks up, and all comes to a quick stop (BL2 and GP20 did this for me). A strong hint that you have a cracked axle collar is when you notice the wheel/bearing assembly slides out of the axle collar very easily. Replace it with a new collar, which is a very tight fit, but make sure the bearings still rotate. Then you need to slowly jiggle the new wheelset back into the truck so that the two square bearings and the gear all fit into their places together at the same time. Often, for me, this step takes the most time!

    Let me know if you have any questions. I have so many P2K's I'm getting good at this! This problem is a certainly pain in the a** but the P2K units are so well done otherwise it is worth the trouble to keep them running. I've never had this problem on an Athearn.

    Last edited by a moderator: Apr 27, 2011
  18. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    FYI, attached is a pic of the "Frisco" GP30 I did, as SLSF 900, that I mentioned in the post above that started this thread. Eeek!

    This is a Proto 2000 Nickel Plate GP30, NKP 900, which I changed to Frisco lettering, and added a few details. I didn't like the way it turned out, so I never finished it - note it still needs a finish coat to hide the name & number change work.

    And, yes, it gives out a nice series of "ca-thunks" when it runs. Good body details otherwise - note the nice handrails. My plan is (probably) to scrap the body, fix and tune the chassis, and try to find another body shell to sit on it. I haven't measured it to see if a GP7 or GP9 body will fit on it, but it looks the same to the eye. If not, I'll probably just scrap it for parts. It sounds like only one axle gear is cracked, but you never know until you take them out and have a look.


    Attached Files:

    gjslsffan likes this.
  19. Iantha_Branch

    Iantha_Branch Member

    Ken, I think the GP30 isn't that bad. Maybe strip the paint and start over. It's good idea you got going there.

    Now I know this thread is about P2K axle gear cracks, but this is a close topic that's already going so I'll ask my similar question. If the moderators feel this should be on a separate thread then move it, or ask me to an I will copy and paste this to a new thread.

    I have an Athearn RTR GP35 and the running quality was so bad on it (I'm spoiled by having mostly atlas locomotives on my layout) I dummied it and planned to run it behind my SD45 (that I just tricked out with lights). But the rear axle of the rear truck wouldn't move. Thankfully I have an Athearn RTR F7A I'm not using at the moment (it's a dummy too), so I took an axle out of it and replaced the "bad" one, I also took all the extra gears out at this time. Still wouldn't move. After further investigation I decided the truck it's self was bad because both the original and the extra wheel set would not stay in the truck. The problem was the whole axle would slide just enough that the bearing would slip of it's "pocket" on the truck. So I took the side frames off of the GP35 truck and stole the front truck off of my F7A (I think the rear truck on the F7 is doing the same thing) and put it on there. Now it rolls, but for some reason it causes a slight short at times. Like it'll be fine, then I''ll bump it and and DCC system will make the noise to indicate a short, but it's not enough to shut down the locomotive that's running around the layout. So any help here?

    Oh and I want to point out on the compatibility part that the F7A truck had EMD (I think they are called blumberg type B or something like that trucks) side frames, and when I went to put the Alco FB1 side frames on they where too big. FYI this F7 is RTR line, not BB kit.

  20. meteor910

    meteor910 2009 Engineer of the Year Staff Member Supporter

    Joe -

    Regarding Kato from Japan vs Proto2000/Athearn, etc from China: In my opinion, and from my experience with some, or many, of each ..... Kato's drives are far superior to most of the others and are, at least, equal to the best from others. Regarding fidelity to the prototype, Proto2000 and Athearn are better than Kato, in some cases much better. Regarding painting and lettering, Proto2000 and Athearn are very much superior to Kato.

    Just my thoughts, others may have different views. Kato has not done a lot of things in HO.


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