Autobox

The imported BigHorns are often fitted with a 3-speed + overdrive automatic transmission. Compared to contemporary UK transmissions, its pretty poor. But it can be messed wth to make it a whole lot better.

Straight from the boat, the imports often rev madly, and switch between gears at strange moments. This is down to the throttle position sensor TPS- see below, or the full story on ITOCUK

The gearbox is made by Aisin-Warner and is a AW30-40LE, its potentially possible to get a filter from an auto transmission specialist, but below is the DIY method.

	The diesel injector pump, with the fuel filter to the right..... This is TPS, on an import, its often almost fully clockwise. Loosen the screws and move it to a more central position, and there will be less hunting between gears. On mine the OD light now flashes, when going too slowly for the OD to be engaged. This doesn't seem to be a problem
	How to change the auto transmission filter. Jack up the vehicle....
	Here is the sump for the auto box. There is no need to disconnect the dip-stick, its on a slide joint.
	Here is the sump on the floor. The amount of "dirt" is clearly visible The original gasket was some kind of jointing compound.
	Now the sump is off, the filter - the flat plate is easily seen and removed. Everything has to be kept surgically clean. Dirt inside a box will kill it.
	The filter can be gently prised apart, revealing the fine metal screen.
	I used brake cleaner to clean everything up. Here is the mesh 1/2 cleaned. Once cleaned, the filter can be re-assembled and the edges crimped over with a pair of pliers.
	Here is the sump cleaned up ready for re-fitting. I've made a gasket from gasket paper. I didn't use silicon, as a stray blob can wreck a gearbox. A spot of Loctite or spring washers are needed now to stop the bolts vibrating loose. Refill the fluid, drive it around for a day, and then change the fluid again, as it isn't possible to drain it all first time around