I can stop the dough hook with hands in 1st gear but motor still turns. all gears good and no broken keys

You have lost 1st gear. The gearbox will require dismantling and replacement of the 1st gear part (diving key) if they are still avaliable. I wouldrecommend contacting yout local hobart call center and speaking to their technical team about the age and probability of parts

To give the mixer strength it has planetary gears. Something may be wrong in the gear section

Hi HENNY346. Your Bosch mixer is belt driven and from the description of your mixer’s symptoms I suspect that the drive belt has come loose or failed completely so it stopped driving the dough hook. You say that when you turn the mixer on, it makes a noise, which may be the motor running without any load, but your description of ‘noise’ is very vague.
The good news is that you should be able to diagnose and fix this quite easily (OK, maybe with a little effort) by yourself, if you are a DITY type person, feel adventurous, and your mixer is not under warranty.
Here are links to two online parts vendors for your Bosch mixer that also provide an exploded view diagram along with part names, numbers and prices. They are: Cook's Quarters and AppliancePartsPros.com It can be very gratifying to go “under the hood”, figure out what’s wrong and fix it yourself. Good luck , I hope this helps. Howard, Burke, VA
If this solution was helpful, please rate it, thanks! – hslincoln

Hi. Stop using your mixer. If your mixer is still covered by warranty, call Kitchenaid Customer Service, they are very good with warranty repairs.

If your mixer is out of warranty, remove the silver band that surrounds the top of mixer. Remove the top cover. At the front of the mixer, locate the transmission housing which is now exposed. Examine this housing carefully for cracks. If you find cracks anywhere in this housing, you have found the under-engineered plastic transmission housing. Kitchenaid's replacement housing is made of metal. Your plastic housing has no business being in a mixer that is marketed as being able to mix bread dough. It cannot!

If you're confident that you can make the repairs yourself, go to the Kitchenaid website and download the parts drawings. Remove the Trans. housing, remove the worm gear shaft assembly which is driven by the motor.. Remove and save as much grease as necessary to thoroughly inspect the worm gear. Inspect the worm shaft bearings. Look for cracks, or missing pieces on the bearings. Look for crunched cogs on all gears. Be prepared to wait at least a month for your parts to arrive after you order them. The replacement grease should be Shell Darina 2, or Chevron FM ALC EP 2.

If you're not confident about repairing this yourself, call Kitchenaid and determine the nearest "approved" repair shop.

You may be able to pressure Kitchenaid to pay for the damaged parts in your mixer. They are still installing these plastic Trans. housing on new mixers. Insist on a metal cover when replacing. Apparently, Kitchenaid feels no shame in their manufacturing process, and will not issue a recall notice for these housings. They are substandard at best.

If you found this solution helpful, please rate it. Good luck! ricardok45.

It sounds like you sheared a key in the transmission.Does any gears work?were you using 1st gear for dough?

In what speed is it slipping?You only use 1st speed for dough,right?Can you put it in gear and stop the hook from moving with your hand?Let me know.

When you say lag and catch up. This may not be a issue. I have seen this with dough and a spiral hooks on all sizes of Hobarts the hook and dough get in a position to push the hook forward and the drive gears catch back up the hook. in fist gear on the 20 quart this is common for sure. but its normal. if you have a real slip from a sheared key it will not take long to where you can hold the planetary shaft with your hand and stop it. another slip that might be possible is if your mixer has the first generation worm shaft gear Assembly. when it is worn out it will slip you. this is the shaft that drives directly off the motor. you can tell if it's first Gen by it has a large spring on it. the tow later versions are all keyed to the shaft no chance to slip unless a key shears.
Michael

amy, depending on how old your mixer is there are 2 types of clutches for 1st gear.these could be your problems--a key is sheared on the shaft--shaft/gear is broken.the bottom part of the mixer where you put on the attachements is called the planetary,does it look like it has moved down?you could tell if the dough hook,wire whip,ect,ect is hitting the bottom of the bowl.if this is the case its just simply tightening the 2 nuts next to the beater shaft.if this is not the case you would have to dissasemble the transmission.let me know.

it sounds like you may have a sheared key on one of the shafts.with no product in the mixer will it run in any other speeds?when mixing pizza dough you should only use 1st gear.if it does run in other speeds you have a sheared key or broken shaft,if it doesnt run in any speeds drop the planetary and check the key on that shaft.