Drive belt keeps coming off when you move the hydrostat lever have new belt on

If your 1986 Cub Cadet Hydro 1210 is experiencing difficulty moving forward but works fine in reverse even after changing the transmission filter and fluid, there could be a few potential reasons for this issue. Here are some steps you can take to troubleshoot the problem:
1. **Check Drive Belt:** The drive belt is responsible for transferring power from the engine to the transmission. A worn or damaged drive belt can affect forward movement. Inspect the drive belt for any signs of wear, fraying, or damage. If the belt is in poor condition, consider replacing it.
2. **Check Tension of Drive Belt:** Ensure that the drive belt is properly tensioned. A loose drive belt can lead to slipping and difficulty in forward movement. Adjust the tension according to the manufacturer's specifications.
3. **Inspect Linkage and Connections:** Examine the linkage and connections between the control lever, transmission, and the drive system. Loose or misaligned linkage can result in improper engagement of gears, affecting forward movement.
4. **Hydrostatic Transmission Issues:** Since your Cub Cadet Hydro 1210 uses a hydrostatic transmission, there could be issues with the hydrostatic unit itself. Check for any signs of leaks, damaged hoses, or worn components in the hydrostatic transmission system.
5. **Transmission Oil Level and Quality:** Ensure that the transmission oil level is correct and that you're using the recommended type of oil. Poor-quality or incorrect transmission oil can lead to performance issues.
6. **Air in the Hydraulic System:** If there's air trapped in the hydraulic system, it can cause issues with the hydrostatic transmission. Bleed the hydraulic system to remove any air bubbles.
7. **Transmission Pulley and Sheaves:** Check the transmission pulley and sheaves for wear or damage. If these components are not functioning properly, they can affect the movement of the drive belt.
8. **Check for Obstructions:** Inspect the underside of the mower deck and the drive system for any debris, obstructions, or objects that might be interfering with the forward movement.
9. **Professional Inspection:** If none of the above steps resolve the issue, it might be a more complex problem requiring the expertise of a professional technician. They can perform a more in-depth diagnosis of the hydrostatic transmission system and identify any underlying issues.
Keep in mind that working with mechanical and hydraulic systems requires knowledge and expertise. If you're not comfortable performing these checks and repairs yourself, it's recommended to consult a qualified technician who has experience with Cub Cadet or similar equipment.

that ones a hydrostatic drive , 1st id look at manual drive disengage lever its on back near the hitch , if this has been disturbed then it for sure wont move , then id go on to look at drive belt , there's a little plastic fan u can see thru crack in back plate it should turn with engine (Pto not required) other than that id look at shift lever to see it still attached and moving something . after that its on to a repair shop to get the transaxle fixed

Is the hydrostatic drive disengaged? On some mowers there is a lever on the hydrostatic drive you can flip to disengage so the mower can be pushed or towed. Other possibility is a broken hydrostatic drive belt.

There are five things that could be wrong. no.1 the switch to turn it on is bad, no.2 the electric clutch is burned out, no.3 the wires are broken or bad connection, no.4 a blown fuse, no. 5 broken drive belt or belts. I have provided a link to the MTD website with an 800 number you can call to verify this. MTD Products

If there is too much play in the drive belt due to belt stretch or linkage wear, the belt will be too loose to drive the tranny but still cause the tranny input shaft to rotate preventing it from being put into gear.
Do the gears grind when trying to put into gear? With engine off you should still be able to push the machine if you put it in neutral. Unless, of course it is a hydrostatic transmission, in which case there should be a lever to push/pull which will put the hydrostat in neutral. This is all assuming that it is a hydro and while running the machine won't move when putting the drive lever into forward or reverse.

look underneath did drive belt snap in two , rear has white plastic fan on top of it that should be rotating with engine running if not yep you broke a belt , don't know about wire could it be from front PTO they are electric so it will need a wire ,one possibility is that drive belt broke slapped front PTO and broke off wire , that musta been some snow your pushin ooh and a reminder never push a hydrostatic drive tractor without pump turning it will dammage it

If you lower the blade deck and get down near the mower, you can see the blades belt on top of the deck. If it is intact, with the engine off, have someone try to engage the blades. A tensioner should move into place to tighten the blades. If it is not, follow the engagement lever to under the dash to see if there is a cable broken or a rod detached.

Post back.
Gary

Likely the belt is mispositioned or somehow in a bind.

i had exmark hydros i was told to never wash them, the water does more damage than good. have you checked or changed your hydostatic oil and filter latley? if you have, when doing that you have to be very careful not to get any foriegn objects in the oil resevoir, dirt, grass clipings, anything will ruin the hydro pump.

is it hydrostatic or belt?probably belt broken.if its hydrostatic,check the release lever at back,that allows you to push it.wont drive if its released