I have 2 of the P2K GP38-2’s that accordind to the previous thread I posted, need to have some shims installed on the worm gear to make it run smoother while going downhill. Can anyone help me figure how to do this. I am not 100% sure how to completly remove the shell. Is this a problem I would best leave to someone with some experence? Anyone that can help with maybe some pics or maybe a tutorial would be greatly appriciated. I would like to be able to run my trains on the upper level. Thanks a million and Have A Happy Holiday Season. Mike
At the risk of raining on the parade I must say this may or may not turn out to be simple. The end play may or may not be in the worm gears, and may or may not be what is actually causing the problem. May be a motor issue that requires the armature to be shimmed. May be a brush issue. I wouldn’t be afraid to take it apart to try to find the problem, but you may need some help and that wouldn’t disturb me either if I were you.
To remove the shell you have to unscrew the coupler pockets and remove them. Next you slightly turn each truck, look for the screw under each one and remove it, you might want to do this in a very well lit area as they are hard to see. The shell will now come off.
Ok so now I have the shell removed, How di get to the worm gear to shim it? There is about 1 motor revelotion befor the wheels start to turn is this normak or do I need to do the shimming thing. Mike
Mike,
The worm gear cover is also the truck retainer, so the chassis needs to be on a flat surface before you remove the covers.
The covers snap on to the truck tower w/ latches on each side. To remove, gently pry one side w/ a small screwdriver. You should keep finger pressure on the rounded top because it can fly off to never-never land. If you feel the cover isn’t releasing from one side work both sides.
A full motor turn of play is a bit too much, I try to keep it to about 1/3 to 1/2. Some feel that all play can be taken out, but I have always felt the slight play helps for initial movement of the truck gears (some built in mechanical advantage).
I don’t have any part # for the various shim wsahers as I have been using an assortment that I’ve had for years. Others may help out for them.
The shims are placed between the square bronze bushing and the worm. Ideally, one shim on each side of the worm would be best, however pending the thickness and trial and error, you could have all kind of combos and I don’t think you want to remove the universal to shim the motor side.
Once you find the shims desired for eliminating the play add a dab of Labell 106, install the cover and test run the loco. I will run it up on a test track in both directions to get the lube moving through the truck.
The real test will be when you run them on a downhill. The surging trouble should be eliminated or drastically reduced.
I have a pair of P2K SD7s that even after shimming and reshimming will still surge from time to time on a downhill, especially with a long loaded train. I stop this by adjusting the throttle (slowing down) and it smoothes out.
I hope you can eliminate the troub
Thanks all for the help especially bogp40, that was what I wanted to know. I took one of the P2K’s apart and found the worm gear and as I suspected when holding the wheels so they won’t turn, and turning the flywheel the worm gear will move back and forth. I am suspecting a .010’’ shim will be alright. Do I need to do both gears or will one do? I am waiting for a call back from Walters, I am sure they will do me right. Thanks again. Mike