MTH Premier Diesel Couplers

 Depending on the clearance, you can either cut the back of the box off (and that tiny tab on the back of the coupler), or use the new#743 short coupler or #806(old one).

I think the idea from MTH was to use Kadee 806 couplers originally.  However, I wouldn't recommend those, especially if you have sharp radius curves.  Another option is often cut the loop off the trucks since you're not going to use it. 

My preference is to modify the 805 or even better 740/745 coupler gearbox by clipping enough off the back to allow a medium shank coupler to function on the locomotive.  Obviously the plastic gearbox are easier to trim, but you can also cut the metal gearbox if you so choose.

If you need a photo of what I'm talking about I can post one this evening.

Great responses so fast!

If I use the #743 short coupler is there any disadvantages to that? Does it require any modification to fit?

Thanks.

 The 743 is just the newer version of the 806. It is a short coupler. It doesn't have the same length shaft so it doesn't allow as much space inbetween cars. It also id designed opposite the regulars so that the spring slack works when pushed instead of pulled.

 Using the larger couplers and then cutting the back will give more space between cars and give the slack runout that helps with softer starts.

Not all MTH engines need the couplers modified.

The coupler on the bottom says 085-3. What does that mean?

OK I modified this one and yes that is too short... when you guys say 740/745 which one specifically should I get? I want the longest possible I think.

Thanks.

Kadee #740/745

http://www.kadee.com/htmbord/page740_745.htm

What screws hace you guys been using to install yours? The ones that MTH supplies are el cheapos and strip out really fast.

 I believe that the MTH ones are M2. Metric two MM. I have not had any problems with mine. I do have a M2 tap for chasing out holes which helps if there's a burr inside.

 Looks like they're out of stock at the man.

http://www.aristocraft.com/TAP...FOR-TRACK_p_416.html

The MTH screws are 2mmx8mm.

The Kadee 804/805's will fit in the 4-axle diesels and clear; with the 6-axle diesels, you need to shave about 1/8" off the back of the box (I just cut off all of the area beyond the edge of the rear mounting hole.)

Mike I think what I am going to have to do now is tap the hole to 2-56 and use those screws.  2-56 is just a hair larger than 2mm so I think it should work.  1-72 is a hair smaller.