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strange running of an equal pair of GP-7' s

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  • Member since
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  • From: high desert so cal
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strange running of an equal pair of GP-7' s
Posted by BIG JERR on Saturday, November 5, 2011 7:28 PM

I have a a pair a identical GP-7 P2k w/stk dcc/sound ,there my go to guys and run in mued/same address ,they are about 1-2 years old ,got on clearance from T.W. dont run em alot as I'm under construction . I use a digitraxx zephyr in command w/ a 5amp db150 for power.

heres the deal,I noticed that they were running with a slite skip meaning at a slow yard speed they have a slite stall on time at a count of 3 ,ex. 1 2 stall  1 2 stall  1 2 stall . they do it connected ,disconnected it did not matter sound was constant just a slite stall in running gear ?

I'm still thinking its in the signal or power but none of the other locos do it ,and split gears is a possibility but didn't think the silver box p2k's had the problem,and the skip is in or appears in TIME  even when separated very strange ,any Ideas ?

again its very slite but notable ,track is clean .....Jerry

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Posted by cacole on Saturday, November 5, 2011 7:34 PM

Do you know what brand and type of decoder is in them?  You don't mention sound, so the decoder has obviously been an after-market install. 

You may need to change the decoder to one that offers better slow speed control.  If the decoder you're using has BEMF, turn it off.

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Posted by locoi1sa on Saturday, November 5, 2011 7:48 PM

Jerry.

 I don't believe the color of the box dictates which locos will end up with cracked gears. Some guys in the club have had newer P2K GP units with cracked axle gears. I replaced all four axles in my one and only GP9 with the Walthers replacement kits and 2 have cracked already. I now order them from Athearn. The Athearn gears are cheaper and in my opinion last longer. I take some along to the train shows for a quick repair of someones loco if needed.

  Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

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Posted by BIG JERR on Saturday, November 5, 2011 10:57 PM

Wow ;I"ll check that out ,I have a good supply of athearn sd-40 gears .just didnt think the newer stuff (silver box) had the problem ...

 cacol: there both stk qsi dcc/sound  ,factory install ... thanks again I well change out the gears and report back ,Jerry

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Posted by mactier_hogger on Sunday, November 6, 2011 5:59 AM

What are the Athearn part numbers for those gears?

Dean

30 years 1:1 Canadian Pacific.....now switching in HOSmile

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Posted by richhotrain on Sunday, November 6, 2011 6:11 AM

mactier_hogger

What are the Athearn part numbers for those gears?

Part Number ATH 60024.  They come six in a bag.

Rich

Alton Junction

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Posted by richhotrain on Sunday, November 6, 2011 6:16 AM

locoi1sa

Jerry.

 I don't believe the color of the box dictates which locos will end up with cracked gears. Some guys in the club have had newer P2K GP units with cracked axle gears. I replaced all four axles in my one and only GP9 with the Walthers replacement kits and 2 have cracked already. I now order them from Athearn. The Athearn gears are cheaper and in my opinion last longer. I take some along to the train shows for a quick repair of someones loco if needed.

  Pete

Now isn't that incredible?   First, the original PK2 gear cracks, then Walthers buys Life-Like, then Walthers Proto produces gears that crack.  I am sure glad that I bought the Athearn gears way back when.  Walthers must be using the old Proto gear molds.  Shame on them.  The cracked gear problem has been quite well known for years.  Also, it is hard to believe that Walthers Proto is still producing new diesels with the same cracked gear problem.

Rich

Alton Junction

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Posted by richhotrain on Sunday, November 6, 2011 6:27 AM

BIG JERR

I have a a pair a identical GP-7 P2k w/stk dcc/sound ,there my go to guys and run in mued/same address ,they are about 1-2 years old ,got on clearance from T.W. dont run em alot as I'm under construction . I use a digitraxx zephyr in command w/ a 5amp db150 for power.

heres the deal,I noticed that they were running with a slite skip meaning at a slow yard speed they have a slite stall on time at a count of 3 ,ex. 1 2 stall  1 2 stall  1 2 stall . they do it connected ,disconnected it did not matter sound was constant just a slite stall in running gear ?

I'm still thinking its in the signal or power but none of the other locos do it ,and split gears is a possibility but didn't think the silver box p2k's had the problem,and the skip is in or appears in TIME  even when separated very strange ,any Ideas ?

again its very slite but notable ,track is clean .....Jerry

Jerry,

As already suggested, it may well be cracked gears.  At slow speeds, the 1-2-stall is a sure giveaway.  Actually, on my locos with the problem, you can see a slight wobble and a "clickety-clack" sound.

Let us know what you find out.

Rich

Alton Junction

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Posted by BIG JERR on Sunday, November 6, 2011 8:52 AM

I well get back ,gears would be an easy fix for me compared to messing with cv's or motors..Smile But on the other hand they shouldnt fail in the first place.

BUT its a lil hard to conceive both locos would crack gears at the same time in the same place ,note the in time 1-2-stall in harmony even when unhooked from each other an seperated ,this is why I didnt suspect the gears.. I well CRACK em Winkopen after church..Jerry

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Posted by richhotrain on Sunday, November 6, 2011 9:57 AM

BIG JERR

BUT its a lil hard to conceive both locos would crack gears at the same time in the same place ,

No it isn't.  Sorry to disagree with you but if the original production run was screwed up, they do tend to show up at the same time.  Happened to me.

Rich

Alton Junction

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Posted by rockislandnut on Sunday, November 6, 2011 3:11 PM

TA462

This is the first time I've heard of the cracked gear issue in a newer Proto GP.  How old is the loco?  It probably is a older model, one of my ONR GP9 sound locos had the same problem but it was built around 7 years ago.   It's also the first time I've heard of the replacement gears cracking too.  I hope Walthers didn't cheap out when they reproduced them again.

BIG JERR said in his OP that the engines were 1-2 years old.

Wanna borrow my glasses? Laugh

Wadda ya mean I'm old ? Just because I remember gasoline at 9 cents a gallon and those big coal burning steamers.

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Posted by mactier_hogger on Sunday, November 6, 2011 3:37 PM

Thanks for the part number richhotrain!

 

Dean

Dean

30 years 1:1 Canadian Pacific.....now switching in HOSmile

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Posted by richhotrain on Sunday, November 6, 2011 4:05 PM

mactier_hogger

Thanks for the part number richhotrain!

 

Dean

Glad to be of help !

Rich

Alton Junction

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Posted by BIG JERR on Sunday, November 6, 2011 4:17 PM

well .I dont think the gears were cracked but I changed them ,#1 the problem or surging is gone today in the 2nd loco did not check though till I already changed gears in first loco. #2 Ive changed a few of these gears in gp's & fa's but never ran into any as tite and hard to remove as these ,I mean I thought they were glued on had to put the blade of a small screw driver between gear and bearing and pry with force to gettem off only to find the new athearn gears were even more difficult to get on ,had to use a small vise to press em in ,never had this with other units they(gears) would just slip off with little or no force.

I dont know looked at every gear under magnifier  no sign of a crack ,I can usually see the crack under a magnifier . I wish I would of done it last night when they were acting up ...Jerry

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Posted by BIG JERR on Sunday, November 6, 2011 5:50 PM

yes David: thats what I have experianced with others in the past,but not the case here these were more than snug , so snug they had to be pryed off. ...Jerry

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Posted by richhotrain on Sunday, November 6, 2011 5:55 PM

BIG JERR

yes David: thats what I have experianced with others in the past,but not the case here these were more than snug , so snug they had to be pryed off. ...Jerry

That may be your problem if they are that snug.  Maybe they need to be lubricated instead of replaced. 

Is the lubricant around the gears gummy?

Rich

Alton Junction

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Posted by BIG JERR on Sunday, November 6, 2011 6:24 PM

thanks Rich ,yes there was a lght lube on and around the gears ,very light and not gummy . to be honest Im thinking it was some kind of glitch in the signal or or ,man I hate to say thisEmbarrassed umm maybe my track isnt as clean as I thought .....Jerry

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