Seeking ADVICE on my hydo trans.

[Strokerace2639 4]

Hello all, I have a 1990 312-H in my possession that I have used for SEVERAL years. The trans has started to act up for a while. at first it would jump from forward to reverse on its own. even though it was very had to move the direction lever

by hand. then it became "LURCHING" ( almost picking the front wheels off the ground) on movement. the only way I have found to stop it is put the mower in very low idle move the direction lever to the forward and then increase throttle  to get up to speed. 

What are the suspect issues and are there parts still out there to fix any issues?

 

Feel free to ask any question you have have.

 

Thank You,

  AS

[gwest_ca-(File Mod) 12,280]

Sounds like you may have linkage/control problems. Have you removed the seat pan to clean the top and front of the transmission?

 

[Handy Don 16,752]

Yep. One or maybe several places in the linkage are out of whack due to wear or debris. 

[squonk 46,874]

Cam and guide plate wear out 

 

[953 nut 66,614]

Sounds like a bit of deferred maintenance issues. The cam and plat as Mike @squonk mentioned are the prime suspects. Read through the manual Gary @gwest_ca provided and be sure your linkage is not binding someplace. If you need the cam and plate K&B has new ones.

 

[Strokerace2639 4]

4 hours ago, gwest_ca said:

Sounds like you may have linkage/control problems. Have you removed the seat pan to clean the top and front of the transmission?

 

THANK YOU. that will be helpfull.

 

[Lee1977 7,638]

My 520-H was almost imposible to get out of reverse when I got it,. would have to hit the brake to get it to release. Found the cam had a groove worn in the and the cam plate worn.

Replaced both and new heavy duty 1/4" heims joints on the control shaft...

 

 Lee1977