A500/A518 Cars, OD and L/U on a toggle or auto?

fullfloater said

I just put a A518 in my 79 Warlock with the 2 pin connector non lockup convertor. Was a little chore but got it going , I wired a toggle switch to blue wire hot and orange etc wire to ground . I have no overdrive , have checked hot wire using pin ground on frame ground and it’s all good . Trans feels firm and solid , bought it out of junkyard with 65,000 miles out of a church van . Going to service and replace overdrive solenoid but I am not sure if this will cure it . Any trans guys out there that can give me some ideas , I see a lot of people put switch on ground instead of hot but I have read people do it both ways . Thanks

Click to expand...

The OD solenoid would be the first thing to check for sure.
If the pan was clean (only normal crap in it) the OD unit is probably ok.
Since OD gets it’s apply fluid from the 3rd gear circuit you know thats there.
Good chance it’s the solenoid.

As far as the electrical goes I used relays to do the ground switching for the solenoids and the hot is a key switched supply.
Also used adjustable pressure switches so with my cabin switches in Auto mode it shifts 123 OD at 60 and lockup at 70 fully automatic.
When slowing lockup turns off when below 70 and OD turns off at 60 and the trans returns to 3rd.
With both switches in the cabin in the off position the trans acts just like a 904 with the low geared first.

With Nitto 245/40-18 high performance tires in the back and 3.55 rear gears it ripped a stock driveshaft in half off a light.:D