Lionel SD70M motor issues?

Also its TMCC if that helps. Thanks!

Some people with Cab-2 have left the train brake on by accident.  Check there?

Thanks for the advice but sadly not the issue. It is one that is definitely mechanical in nature. When you power up to around 70% power You can give the engine a physical push and it will start moving. After a few seconds it will be moving at full speed. If you reduce the power to less then 50-60% of full power it will come to a stop instantly. But you will here the traction motors still humming as it try’s to move and then tripping the track power breaker.

As a side note, this was a used purchase that came with this issue. Not an issue that just started or came on slowly. It has been this why since I got it. I’m guessing that’s why they sold it.  

Good background info.  If you pulled the motor(s) and lubed the worms did you check the copper thrust bearing that the worm rides on?  There is a proper orientation and I can point you to a drawing if you would like.  On this older style truck I have seen the idler gear that is studded to the side of truck wallowed out causing gear binding.  

Might try and set the fuel tank on something to elevate the trucks. Then use some jumpers to power it up and see if one or both motors/trucks are binding.  Then report back your findings.  

Ok so I have done that and it seems as though the front is worse than the rear. The rear seems to react correctly to the control of the system but the front does not do as well. The front also seems to make more noise then the rear does as well. As far as the idler gear goes everything seems to be normal. No excessive wear. Now the copper bearing, I’m not sure of that. Maybe worth a look?? Thoughts? Also I’m going to try and attach a video or 3 to this as well.

Another video here

And a 3rd

And I also want to post a pic of the front truck on the track. Seems like it’s not right. The rear set of wheels seems to sit on the track and can some times drop down along side the rails when going through a switch or around a curve causing it to derail. Maybe this is all related? Bad truck? Bent frame? 

That noise is way loud.  We have some friction or binding going on.  The conductor side side frame looks messed up.  Take them off both side and redo your test.  See if that changes it.

Ok so with out the trucks it way quieter then before. Attached is a video. So truck issues I’m guessing.

Do the trucks seam to roll freely when removed from the motor?

Ya seem to move with out issue. Seems to be more of an issue when it’s all assembled. It takes a ton of power to get them to move and stops once you get under 50-60% of full.

You are certainly ambitious.  I did not expect you to disconnect the trucks from the motor.  I simply recommended removing the truck sideframes.  Their brake details sometimes rub or catch the traction tire and bind the axle.  Now that the motors are pulled then 2 things. Make sure the copper bearing is in place and right orientation (see part #13 below).  Also, drive axle 37B shouldered bearings need to have flats orientated properly and the rim in the groove.

Ok so it seems as though the bushings are upside down. Also after some extensive bug hunting, it seems as though we’re missing part of the front motor mount as well. Which also might explain the way the truck sits and most likely it’s binding everything up. 

The exploded view shows the bushings flat side up (so that they are visible) but actually the flat side goes down.  The motor mount must not be compromised otherwise it will throw off the axis of the worm gear and cause binding with the ring gear.   Good news is the mount is only $8 and still available.

Ya for sure, part of the front mount is missing so that seems to explain the issue there. I reassembled the rear truck and it’s smooth as butter! With out the front on it very quiet now. I’ll get the mount ordered in the morning when they open. Thanks for the help! You made that a lot less painful to deal with.

Different question for ya, it has a standard Duracell non rechargeable 9v battery in it. Shouldn’t that be a rechargeable battery?

Alkaline only.  Loco does not recharge the 9V battery. 

You can order the part from Lionel but they will not ship until employees are allowed to return to work. 

Thank you for all the help. Ill let you know once i get the part in. And you were right. Lionel is not shipping till June. Thanks again!