Gearbox Reflection

Gearbox Reflection

The past few weeks have seen us dismantling, assesing and reassembling automotive and marine transmissions. We have covered a variety of transmissions; Toyota 4k manual gearbox, Outboard gearbox, Sturn drive and hydrolic marine gearbox.

Penta Hydrolic Gearbox

During this excersize I gained first hand experience with gearboxes. I feel it is alot easier to understand how the gearbox works when your able to see how the parts move within the box. It also helped illistrate the importance of following a dismantling proccedure and during reassembly, the importance of fitting each part correctly.

Visual inspection is a major part of gearbox reconditioning, this excersize has taught me how to identify damage and wear. For example we check the case hardening on all gearbox components, if the hardened surface has any nicks or chips then this part is destined to fail. Gears are checked for wear, damaged teeth and excess play. Bearings are also checked, it is important to ensure that all bearings are running on hardened surfaces.

                       

The synchromesh unit is very important. Ensure all parts are present and check for damage and wear. It is importannt that the baulk ring in correctly fitted or it will not synchronise the gear speeds.

 Runout is measured on all shafts. Housings are measure for distortion. Oil pump clearances are checked agaist specifications. The bevel gear that drives the propellor is set to ensure correct contact.

I also learnt how to calculate a gear ratio.

Most important when dismantling an automotive gearbox... Dont loose the tic tac's!!!