Where to Jack

[mtheo]

I haven't tried driving up on the 4x4 with my Monty but did with my last trailer, didn't get the axle up high enough to get the spare on that was not flat. still had to use the jack. I also didn't feel real good about the way it sat on the block.
Now I just use an 8 ton jack right off the bat, right under the axle between the U bolts.

[Wrenchtraveller]

Placing the jack right on the axle between the U bolts is the best position IMO and this is exactly what the factory rep told Indyroadrunner. I have been lifting trailers this way for 30 years with no problems. Lonnie, also recommends this and he is a Tire Pro with years of experience. As a millwright I use hydraulic jacks all the time and my 4 ton bottle jack is all I need on my Montana. You are only lifting one end of a 6000 pound axle so it should take only about 3000 pounds of lift to raise the tire off the ground. You are lifting the suspension off the ground and the frame moves very little if even at all.
Lifting the frame places all kinds of strain on your whole unit and it requires a higher lift because your suspension hangs down. I would never do this to any trailer I own. This is one reason I prefer to buy new units so I know what has been done to them.
Montanas have a manufactured rolled I-Beam frame, not a shop built welded I-Beam like you see in some cheaper units, but no I-Beam is made to be stressed in one area, the way that jacking the frame does.

Lifting on the axle between the U-bolts can be done with the trailer attached to the TV or unhooked, either way. It puts no strain on your landing gear as the frame barely moves.