633A104 Transaxle Help Needed

I recently purchased a 1978-80s model Sears Craftsman GT/14. It is a vari-drive tractor with a 633A104 transaxle. I recently struck an interest in this hobby and I have little understanding on the differences on all of 633A transaxles. From what I have read I should be staying away from hydro and vari-drive tractors. With my transaxle being a 633A why is it vari-drive? Can it be modified to be used without the vari-drive? What models of the 633A are acceptable to use?

I didn't know 633a coupled with VariDrive was a thing until now... anyone else? Lol.

Any 633a hi/low would bolt right in but it's hard to know if you'd need any other components from the same tractor to make it work. You're going to have to post some pictures of the clutch/belt/VariDrive setup to see what's going on there and come up with a gameplan

I don't think that version of the 633 had a Hi/Lo which is where the varidrive comes into play. Either a jack shaft or engine re-alignment should allow for direct to the trans use.

@Brianator @MightyRaze The tractor does have a Hi/Lo shifter on the right side of the tractor. Pics pending.

Let me Know if another angle will help.

@MightyRaze  @Brianator

Attached is a link to the manual I found for the tractor.

cant attach the link due to new member 7 day restriction.

www.gardentractortalk.com/d3/downloads/69407-917.257030.pdf

It looks like the transmission pulley is offset to accommodate the offset created by the vari drive. The pulley is on a tapered shaft so you can't flip it around, but if you find any other 633 (or whatever the electrolux 3 hi/lo is) pulley you can swap it on and it will be better in line for converting to a standard clutch. You might be able to work with the pulley you have, but it would make less room in the frame to have a clutch. If you have access to a lathe, or were just really good at eyeballing and welding, you could get a pulley from TSC and adapt it to the factory pulley hub. I've reused a bunch of those pulley hubs like that now.

Fixed the link for you.

Looks like it has a standard clutch which is great news!

The hi/low shifter only controls the VariDrive by the looks of it which is also great news, if you can get your hands on a regular 633a with the pulley and hi/low shifter attached then it should be a strait swap and then you only need to remove the VariDrive pulleys and find a belt!

With what you are saying, is it possible I could just do without the Hi/Lo and run a belt directly from the the engine to the transaxle and have a 3 speed? I planned on upgrading to a 2300, but I was hoping to have something to just start with. I am not looking to go more than 15mph, I need the torque for the terrain I want to crawl on.

cmason wrote:

With what you are saying, is it possible I could just do without the Hi/Lo and run a belt directly from the the engine to the transaxle and have a 3 speed? I planned on upgrading to a 2300, but I was hoping to have something to just start with. I am not looking to go more than 15mph, I need the torque for the terrain I want to crawl on.

The 633...100 is a great transmission.  Only thing you would gain with a 2300 is a 4th gear (1st) which is a super low gear and cast iron case. As mentioned, I wonder if a regular 633 or AYP variant pully would put you in alignment with the engine.  Looks plausable.

I have both a 2300 and a 633 or ayp craftsman variant.  Both are Dang Good.  I love the 2300 I transplanted in my 77 sears,  but I am partial to the 633's.  Without the Hi/Low, that is just one less thing to break. 
 

Doubful as @RichieRichOverdrive mentioned it looks like the trans pulley is offset for the VariDrive so alignment will be an issue unless you swap that pulley and set it for alignment, read what he had to say about it.

My machine similar to yours with nothing more than the front pulley flipped to run off the pto pulley (which is a little bigger) has got me to 11mph in 3rd Hi with the bigger tires out back. There's no room to put a bigger pulley on the motor without moving it ahead and that will be a big chore in itself but not as much as trying to relocate/re- engineer the clutch... if you put a smaller pulley in the rear you can gain some speed but the smaller the pulley the more belt slip you'll get and that will slow you down.

Honestly, sounds like it's best to run it as it is and if the VariDrive gives you a problem go with the standard 633a with geared Hi/Low. Forget the 2300, not that it's a bad trans but a 633 is better and will bolt right in if you get the "new style" that has splined axles and the trans spacers built into the casing.

A 2300 with a 6.5" pulley on the motor and the original 8" pulley on the trans (which is either tapered or splined - I've seen both) will get you to 10mph and your reverse gear will be really quick as it seems it drives off of second gear instead of first.