Small Engines (Lawn Mowers, etc.)/Transmission


QUESTION: Hello - I have an older Simplicity 6516 tractor with a hydro transmission.  Over the past month it is going slower and slower up the small incline in my yard.  Engine rpm's remain the same but tractor slows way down.  Drive belt from engine to trans was replaced in August.  Is my transmission going bad?  Many thanks -

ANSWER: Hi Bill  

can you give me model and make  of  hydro transmission unit  , there should be a tag or sticker on it - but if all inputs are good and no  drag or brake bind etc  , sounds like it may be either very low on oil ( possibly cavitating)  or the pump  and or hydraulic motor in the hydro have worn out  hence the slow speed  

let me know  make and model of hydro unit  please

cheers paul

[an error occurred while processing this directive]---------- FOLLOW-UP ----------

QUESTION: OK.  Simplicity 1691263. Transaxle group.  Fluid is full but has not been changed recently.  Do not see exact make and model of hydro trans unit.  Here is a diagram:

Hi Bill  

I would try  changing oil and filter on the unit 1st , then provided  all inputs from  vee belt, pulley etc are ok   and unit has correct fluid and quantity  but is still not moving properly  it may well be the hydro pump / motor unit  inside the transmission

be sure  trans belt has good tension it  and brake system is not dragging/binding
be sure the link from foot or hand control lever to hydro unit is moving the pump swash plate  that goes into the transmission  from the side  ?

if all is good  , then only be the transmission playing up   !!!

see what you can find  , let me know  

cheers  paul  

update  ----has the oil and oil filter been replaced, and unit purged of any air ?incase its dropped its additive pack.

have you checked nothing is restricting flow of oil  from oil tank to pump ie  blocked / restricted tank screen ?

note  be sure that the bypass is not partialy disengaged  or is stuck open
its possible releif valve may be stuck open or sticking

these units have a eaton cam ring  type pump on the top side of trans , and a l/h and r/h eaton wheel motor / with differential gear assy

low flow of oil through system maybe causing  low speed even though input shaft speed is good to pump ,   in hydraulic terms  flow of oil relates  to speed  and the pressure relates to torque  both are quite closely related

as stated earlier  simple things 1st then  if still not responding , decision weather or not to relief valve ,eaton pump , wheel motors.

let me know if anything helps  

cheers paul  

Small Engines (Lawn Mowers, etc.)

All Answers

Answers by Expert:

Ask Experts




Briggs and Stratton MST qualified Tech - Certified Kohler Expert Tech 12 years experience in repair of Small Engines -Briggs,singles, twins Kohler, Honda , Kawasaki ----Husqvarna chainsaws and trimmers -shindiawa -chainsaws & trimmers etc Walker Mowers - Kubota Ride ons - Husqvarna ride on and outdoor power equipment, -Mtd Ride Ons, Push mowers etc


Briggs and stratton MST qualified Tech - Certified Kohler Expert tech 12 years experience in repair of small engines Husqvarna chainsaws and trimmers -shindiawa -chainsaws & trimmers etc WALKER zero turn mowers Kubota Ride on mowers Husqvarna ride on and outdoor power equipment Mtd Ride Ons, Push mowers etc some experience in 2 and 4 wheeler repair - Honda, Suzuki , Yamaha

Qualification - Briggs and stratton Master Service Tech 2005 onwards Qualification - Kohler Certified Tech Qualification - Mito NZQA National Certificate Outdoor Power Equipment Basic automotive trade skills & year 2 & 3 of Motorcycle engineering

©2017 All rights reserved.

[an error occurred while processing this directive]