Hey I have an old simplicity mower that the parking brake stuck on. I’ve been trying for the last few weeks to fix it but I can’t. So I need some ideas. I don’t have many details on it. I bought it for $20. So all I know is it has a hydrostatic transmission that works fine but the parking brake won’t disengage.

SOURCE: vehical stuck in limp mode

This only applies if you have an allison transmission, which based on the problem you are reporting I would guess that you do.

It sounds like your vehicle is stuck in limp mode. This is probably due to a bad NSBU switch(Neutral, saftey, back up) (if you have an allison transmission. Prior to 2002 the NSBU switches had a very poor seal which resulted in water intrusion into the NSBU switch causing corrosion. If the switch is corroded it is likley confusing your transmission. Unfortunatly you cannot repair the bad switch, it needs to be replaced. If you order one through Chevy it will cost around 200 dollars. I found one at merchant Automotive for 91 dollars. ( http://www.merchant-automotive.com/allisonnsbuswitch2001-2004.aspx ).

The switch is relativly easy to replace. the electrical connections are the hardest part as they are glued into the switch. A little heat from a butane torch should soften it up and make the connectors slide off more easily. Other wise you may have to break the NSBU switch appart to remove the connectors.

I replaced the switch for the first time and it took me 15 minutes.

SOURCE: MTD PRO RIDING MOWER/LAWN TRACTOR 18 HP ENGINE HYDROSTATIC DRIVE

In the back of the mower...probably under the seat, there should be a lever to release the transmission, or it is on the back plate. As far as the noise when trying to move drive the mower, the brake in the back, next to the transmission is jammed, use a 1/2 inch wrench to loosen it maybe 1/4 turn and this should unlock the brakes

Harry Goodwin

• 353 Answers
• Posted on May 09, 2009

SOURCE: transmission stops pulling when it gets hot

when was the last time you had the trans serviced?
It could be seizing up from the lack of oil

SOURCE: simplicity mower stalls when brake released

There is another safety switch connected to the parking/service brake. Check that one too. Sounds like its the one.

SOURCE: Hydrostatic transmission doesn't turn drive wheels anymore

It sounds like the oil in transaxle is degraded.The transaxle is supposed to be a sealed unit requiring no service but over time the oil will get dirty enough to cause problems like you are describing.Remove the back hitch plate and look at the transaxle it will have a rubber vent hose or a 1/4 Allen wrench fitting on top. You will need to purchase a battery suction bulb from sears automotive and use it to remove as much oil from transaxle as possible. Warm the transaxle up first by running it around,then suction the oil out.Refill with a good synthetic motor oil 15w-50 or 20w-50 like Amsoil or Mobil 1.Do not use transmission fluid or hydraulic fluid. When adding the new oil back fill it to within 1.5 in from the top,be sure to allow this amount of air space in top of transaxle for expansion.

Testimonial: "This procedure was worth trying, but did not solve my problem. I suspect that there is some other reason my transmission does not drive the wheels."