Most likely problem will be the drive belt--the one from the engine pto to the deck that employs an idler pulley. With the engine safely off/disabled, check the tension of this belt with the lever for engagement in both the on and off position. If the belt is not loose and free in the off position, the belt is either misrouted or the idler is obstructed. If you are not sure that you have routed the belt correctly, do an internet search for your tractor's operator's manual for instructions. managemyhome is a useful site to start at.

I went ahead an mowed with it yesterday evening and the vibration of the blades spinning, liked to of shook me apart !. I probably need a couple of new spindles ?, because these things are making quite a racket !. I will probably need to replace the little pulley brakes too, because they look like their more than half way gone ?.

The only good news is, that the 2 new drive belts I put on are working great ... so I'll mow with it like it is, until I can find out why the blades won't disengage fully ?.

Make sure your belts are on the inside of all the belt keepers. Not sure what you mean by "pulley brakes." With the belts off, your blades should spin smoothly and there should be no up and down woble--that would indicate bad spindles.

I used to have one of these mowers (it was made by MTD, so it's VERY common, with just minor cosmetic changes between brands). My memory is a little fuzzy, but I think there's just one belt from the motor to the 2 spindles, and one belt to the transmission. Engagement is a 'back and down' process where the cut height lever moves the deck away from the motor and engages the blades.
Sounds to me like you've got a belt that's too short.
If you do an Internet search for "TMO-3100002 manual", you'll find some manuals you can access. Also using that model number, you can check parts (like that the deck belt should be 74"), and get diagrams

These spindles can be noisy and run a long time- as long as the blade doesn't rock. They really need to have the OEM 0371a belt as it is a different cut. They should also have the belt guards as they act as they help the belt to pause when the tension off. BTW the belt being burned on the sides are the biggest reason for vibration. Of course, blades need to be in balance reasonably. There is a position/ travel adjustment which is on the RH lower side of the tractor. You would see the rod clevis if you pulled the console cover- but the pin to pull is below and a slight shorten on the rod will keep the deck from travelling further ahead- which will allow an idle if you have the proper belt.

Hey gang, sorry for not responding till now but, the wife and I have been "making our monthly rounds" to the doctors ?.

The deck on this thing is extremely plain and simple, only having the 2 pulleys, nothing else in between.

The deck belt only has 'belt keepers' at the engine end (2 bolts that run along each side of the pulley). My belt is run "inside" of those 2 bolts. There are no bolts or pins around the 2 blade pulleys, they have metal 'guard shields' only ... which I haven't put back on yet, because I wanted to be able to have, a full view of the entire deck and watch what the pulleys were doing ?.

As for "pulley brakes" ... I should of called them "stops" or "pads"? ... they attach to the underside of the running boards above each pulley, anyway, whatever they are called, their more than half way gone ?.

There is 'NO" up or down motion on either pulley that I can detect, with the belt off. When I had the deck out from under the tractor, I looked it over pretty good, checking the condition of the blades (which have seen better days !.... to many rocks around here)) and cleaning all the old grass and etc. from under there. The underside looks as good as the topside .... no rust and not even bent anywhere, really a pretty solid old deck !.

There does however, seem to be a lot of "slop or play" in the side to side motion, which leads me to think that the bearing may be bad ?, because there is a pretty bad vibration when I'm mowing. I checked the blades, themselves, and they don't appear to be bent ?.

Blade engagement is indeed 'back and down' , to some degree, but not really a lot of motion ?. The belt that is on there, is the one that came with mower (when I got it) and had been working fine, until I took the deck off, to replaced the 2 drive belts ?. I have a manual, that I got online for my mower model.

As for the number on the my deck belt, it is not readable anymore ?. I looked at it's condition and it does seem to be 'burned' some on the sides ?. I did read in the manual, about that travel position adjustment and was going to check it, I just haven't done it yet.

So, to recap, the blades are engaged by the action of the deck moving back and not by an idler pulley being employed to add tension to the belt? If so, logic says either the new belt is too smal (did you match the new belt to the old one?) or something (grass, a bent rod, etc) is hindering the deck from traveling to it's complete upward position. Look for anything that is stopping the deck from traveling further up and forward or for any adjustment that would increase that up and forward travel.

Yes, you are correct. The blades are engaged by the movement of the deck, there is no idler pulley. However, I DID NOT put a new deck belt on ... I only put on 2 new drive belts ?. The deck belt is the same one that was already on it and that had been working just fine before ?.

The guards help park the belt, so that may be the factor you are missing. If there is a burnt edge on the belt and you can rock the blades as to indicate the bearings are worn, then do yourself a favor and get new spindles and deck belt. 753-05319 and 954-0371A. If there is a Lowes near you, strangely enough the OEM belts are priced good there. AT least they used to be. MAy have the spindle too.

Just to clarify...
You removed the deck
Replaced the long and short drive belts
You replaced the deck, and now it's noisy and won't disengage?

Did you mount the drive belt to the wrong pulley on the motor and hence, mount the deck belt to the wrong pulley?

Good morning folks. It's been storming here, to much, to go out an mess with the mower, so it's still covered up.

I will put the metal belt guards back on and see if that does the trick ?.

I hadn't thought of checking at Lowes but I will in the future.

... No, I didn't mount the drive belt to the wrong pulley ... that belt had to go on first and goes around the smaller of the 2 "stacked" pulleys that are mounted on the engine shaft and that belt runs along and next to the underside of the frame.

I knew asking about the pulleys was a long shot, and would probably be quite difficult.

Before you replace those guards, make sure the spindles are in good shape - if there's any wobble, you might as well get replacements (start soaking the bolts with good penetrating oil, they can be difficult). These parts are easy to find, and I think they're about $20 each. Get a new belt while your at-it, and use this opportunity to get the blades sharpened/balanced (or get a new set).

"Problem solved" !. I replaced the belt guards and that stopped the belt from moving, when disengaged, just as it did before.

Ultimately, I do have to replace both of the spindles and will also get new blades and a new belt ... while I'm at it.

Hopefully, after replacing all of that ... I will be able to get my mowing caught back up ... and keep it that way ?.

I appreciate 'ALL' of the replies and responses and advise, that I received .... thank you to all.

Carl