DP 350 Variable speed pully came apart and the retaining ring went somewhere. I Can buy an outher ring but I don't how to put the ring back on. Namely compressing the spring.

You have to use a pick shaped like a small hook to get them out. I have done it before. Buy the kit a john deere and have them print you out a diagram of how they go. I can't remember exactly what order it has been a while. But use the pick and work them out. Then clean it all real good with clean rag. Use hydraulic oil on them when you reinstall them. I believe it is a o ring first. Then coil, Followed by another o ring. You oil them up and work em in with your fingers. May have to use old wore out small flathead screw driver so it won't have sharp edges and damage it. And the coil you have to start one part of it and work it in around in circle. You know pull it apart and feed it in.
Now that I think of it I think the coil has to go in first then slide the rear oring in past it and work it in from behind. Then the outher one. But look at diagram. It isn't real hard. Oh ya, You may have to take the outher cover off of it first. Should be one small bolt? Not sure if that was on our 40/20 to or just our 4455. Good luck let me know if you have any questions. I will try to check back.

if you took it apart to change the chuck you might have disconnected some wire id check that first

I had the same problem and searched extensively for a replacement pulley, but couldn't find one. I thought I'd try something else and began looking at Love Joy variable speed pulleys. They function the same way and are much heavier duty that the cast pewter used by Delta. The one problem, they are EXTREMELY expensive. Tried ebay and found a number of different brands and sizes. I recently found and purchased a Reeves variable speed pulley 850C 5/8" bore & 5" OD off of Ebay for just under $30. Well, the motor shaft is just under 5/8" but larger than 9/16" so I was going to use a metal 1/2" ID x 5/8" OD spacer as a shim and file the inside down to the motor shaft diameter, which would definitely work. Fortunately I had an old 1/2 HP motor from an old drillpress and it had a 5/8" shaft. Dropped the Reeves pully right on and mounted it on the DP350 and it ran like a charm. It's a little off of alignment and I had to cut a hole in the top cover for the Reeves pulley to protrude out an inch or so, but other than that it works great. My only fear is that the front pulley might explode now. Guess I'll have to wait and see. I'll bet there'll be a lot of searchers for a 5" OD variable speed pulley on ebay! Hope yours works as well as mine!

A wire has come off the connection between the battery & the trigger or connections the triger & the motor, maybe (Blue & Yellow)

Use a philips screwdriver to undo the screws. The plactic covers will come apart. Best to lift only one side. Be careful when doing this & take note of where the cogs fit into the covers when you lift it. If there is a speed change swich on the top of the drill make sure you know which direction it was swiched to. (1 or 2) This is only a machanical swich but it can be a ****** if you move it & don't put it back in the right place. On some models only the handle will come apart, if so, you are in luck.

When you have it apart have a look at the wireing & find the one that has come adrift. It will be where the wire connects to something. Solder it back on. Don't mix the wireing up. There will be a Red Wire going to the Positive side & a Black wire going to the Negative side.

It's not rocket science. Anyone can do it, with a little care.

Front Wheel Bearing Hub

You will have to remove the brake calipers,hang it,&
remove the rotor,then you can turn the hub & feel the
roughness.

ROCK AUTO.com for parts & look at that hub, so you
match it up the same. Don't get in love with one brand
you like, if the hub looks different at the back where the
speed sensor goes in

You also may find your self buying a torx socket or metric
socket driver to get the speed sensor out. Maybe not

If tools are needed,do yourself a favor & step inside a Snap-On
Truck & just buy one item or so. If you don't ,you won't find those
items anywhere

Hi, it is likely your speed sensor has failed or the wiring is broken. The speed sensor is mounted near the rear of the transmission and has 2 wires attached. Check to see if the wires got pulled. If the wires look good, you can test the sensor if you have some jack stands to put under the back wheels. Make sure the transfer case is set to 2WD. Test procedures are pasted below. Please let me know if you have any questions, and thanks for using FixYa.

OPERATION

The vehicle speed sensor is made up of a coil mounted on the transmission and a tooth rotor mounted to the output shaft of the transmission. As each tooth nears the coil, the coil produces an AC voltage pulse. As the vehicle speed increases the number of voltage pulses per second increases.
TESTING

See Figure 1

Fig. Fig. 1: Vehicle Speed Sensor (VSS) and vehicle speed signal buffer wiring diagram

1. To test the VSS, backprobe the VSS terminals with a high impedance voltmeter (set at the AC voltage scale).
2. Safely raise and support the entire vehicle using jackstands. Make absolutely sure the vehicle is stable.
3. Start the vehicle and place it in gear.
4. Verify that the VSS voltage increases as the drive shaft speed increases.
5. If the VSS voltage is not as specified the VSS may be faulty.

REMOVAL & INSTALLATION

See Figure 2

1. Disconnect the negative battery cable.
2. Disengage the electrical connection.
3. Unfasten the sensor retainers.
4. Remove the sensor and gasket or O-ring.

To install:

1. Install the sensor with a new gasket or O-ring.
2. Fasten the sensor retainers.
3. Engage the electrical connections.
4. Connect the negative battery cable.

Fig. Fig. 2: Vehicle Speed Sensor (VSS) location

Sounds as though you are on the right track. I would take it apart, and see if the trigger could have some dirt or other material causing it to stick, or is it worn to the point that it needs to be replaced. Good luck!

There is supposed to be a snap-ring with covering a cap with a spring that compresses the pulley and holds it together. Maybe one of those pieces has broken or is worn out. Most online repair parts places have an exploded diagram of all the parts and where they go so you can identify a replacement.

This problem sounds like failure of the Variable Speed Potentiometer component. Here is the most helpful Fixya article so far: http://www.fixya.com/support/t6032529-need_replace_speed_control
I have the same problem right now and don't want to pay ridiculously high prices for a small electronic component.
So far, this is as far as I've gotten in researching replacement parts:Vitamix Part #015955
Partstown sells #15955 for $23.39 on their website but I found out they charge $15 for shipping -- for a one-ounce piece of electronics. I won't pay to be ripped off on shipping so I won't buy one from Partstown until I've exhausted less-expensive suppliers. Here is the product at Partstown: http://www.partstown.com/vita_mix/vm15955

Another Fixya contributor, Robert Sadler, said he was going to try a generic potentiometer from Mouser.com. His descriptions are kind of vague for me. I'm not an electronics expert so I'm not very confident I can interperet his description:

"If you are comfortable with soldering, you can get a replacement part at Mouser.com. The pot is a 5k "slimline" made by Bourns, however looking inside the cover it looks like most pots would fit. I ordered one for a bit over $5 and will update when I get it with how it worked. You would just have to solder the existing wires to it." -Robert Sadler

I have no problem soldering the existing wires onto a new component but I don't really know what would be an appropriate potentiometer to buy as a replacement from an electronics supplier. In addition, Mouser's website seems to sell potentiometers only in bulk quantities of 5, 6, 12, or 45 items at a time. I just want one.

If anyone knows how to interpret Robert Sadler's comments, or has actually done this repair, please post below. I'm sure quite a few people would benefit from a high-quality repair at a low component cost.

Hi,
Based on the fundamentals of retaining rings, The filter lens probably fits into the ring housing first, and the retainer ring is inserted inside of the ring, following the lens. The retainer will need to be compressed in order to fit inside the ring, but will snap into a groove once in proper position.
I hope this is helpful... Good luck.