I just got the tranny out of my Donor 93 W250. It was an A518. I went to try and start the motor after tranny removal and got nothing. Tried grounding the neutral safety switch...still nothing. Truck will power up, but no cranking.

Obviously it's looking for a signal from one of the sensors or switches from the tranny...any idea what I need to do to get it to fire?

 

Did you jump the neutral/park interlock switch?
Jump it at the starter solenoid.
Did anything get disconnected by the turbo downpipe?

Jim

 

What Jim said!

 

Neutral safety switch is on the trans, you disconnected it.

Jumper it and you should be good to go.

 

I did try jumping the Neutral/Park safety switch connector....it still did not fire. Do I need to jump it at the starter solenoid instead? There are 3 wires at the neutral/park switch...do they all need to be grounded? I only tried jumping between 2 at a time...so 4 combinations on the 3 wires.

The only things disconnected were at from the tranny and transfer case.

 

Does it not crank at all or just not start? If it just doesn't crank, why not just use a screw driver to jump the starter solenoid?...Mark

 

I wonder if you have to jump the clutch safety connector too? It's a green plug near the e brake pedal. Or near where the clutch pedal would be

 

The neutral start switch has to be jumped between the connector Center Terminal and the chassis ground, it grounds out inside the transmission in Park and Neutral.

The 2 outside terminals are for the Backup Lights.

I MacGyver'ed mine
I started mine with a clip made out of gas welding rod under a bolt head, fit right into the connector center terminal, just be careful it will start in gear.
Saved me from calling a tow truck.

Jim

 

There should be a two wire (pink and brown? ) connector hooked to the little wire coming off the positive terminal, undo that and jump it with a paper clip. That how I start mine as it has no harness in it at all, just the positive cable and that connector. Use a big paper clip as it may get a little warm

 

I was thinking about things after my last post...and got to thinking that the reverse lights work off that switch as well. So only one of the wires is actually the neutral/reverse switch....and it would need to be grounded to the frame.

So basically what you said Jim...Will give it a try and let you know.

 

Well I grounded the center connection in the Neutral/Reverse light switch connector to body ground...and...started up fine.

Thanks for the advice everyone....appreciate it!!

 

That is great, glad you finally got it started, I discovered my fix in a parking lot when I could not get it to start after my new transmission, mine also has an oil pressure interlock relay and my starter interrupt relay for the alarm that disrupt the start signal.

The neutral switch was new but intermittent, I first noticed it in the backup lights and progressed to the no start.

I made the jumper out of gas welding rod and secured it under one of the pan bolts so I can stick the connector onto it if I needed it again.

Jim