Hello everybody...
First post of many I am sure.
I have a 1984 D-150 that I plan on tearing down and restoring. Maybe overboard for a truck like this but I consider it warm-up for the many other projects I hope to complete throughout my life. I love the body style and stance of these trucks and plus it will make a great parts hauler.

Anyway, in my quest to fill out the pre-deconstruction checklist I have stalled on picking a transmission. (Puns always intended unless otherwise specified.) The truck currently has a LA 360 that I know is not original but I plan on keeping and stroking. Nothing drastic but it should make for some fun on the street. The requirements I need to fill include:
1. Automatic.
2. Overdrive, a must since I do a lot of highway driving.
3. Non-electric shifting since I don’t plan on installing a computer.

I have searched and found a lot of information on the A518 / 46RH which looks like will fit the bill, but I have read that some years of these models used electronics to shift the OD and some did not. This is my first foray into dodge country so I haven’t been able to quite sort it out yet. I don’t’ have any problem pulling one from a junkyard and rebuilding it so I just need to figure out what I’m looking for when I go parts diving. BTW, the existing transmission is a 3 speed (904 series I think) that still shifts great but is not going to cut the highway driving.

Thanks in advance
bnhynum

http://sunlightonchrome.com/phpgraph...ghtQuarter.jpg

 

While I can't add anything constructive to your post, WELCOME!

 

You could also consider a GearVendors O/D unit, which is seperate from the trans.
This site has loads of trans info/parts http://www.transmissioncenter.net/dodge.htm

 

The stock trans. should be a 727. I dont know much about a overdrive trans other than dodge had some problems with the overdrive units. I think the 518 started in '88 or so. Time to hit the junkyards. I think you can rig them up with a pressure and toggle switch to engage the overdrive but not sure on that.

 

http://www.transmissioncenter.net/SwapInformation.htm

This site has the info on using a vacuum switch and two oil pressure switches to control both eht lock-up and the overdrive.

 

ok. so this guy is telling me that my 3 speed is secretly a 3 speed with OD its just missing some valves and stf? the guy makes it all out to be so simply but frankly im lost reading that.

 

Yes, a 518 OD trans. is essentially a 727 + OD.

 

The 518 has all of the same ratios of the 727. just like the 727 some models have a lock-up torque converter, some don't. The major difference is the tailshaft is a lot larger to accomidate the extra gear set for the overdrive. If you installed the 518 and didn't wire anythig , it would drive exactly like a non lock-up 727, only giving you 3 forward gear. A switch enables the overdrive. Most vehicles have a switch or another position on the shifter that disables the overdrive. The addition of the vacuum switch and the two oil pressure switches enables the overdrive and lock-up to behave normally. This way you can turn on overdrive and drive it as if it was originally installed in that car. With the addition of a toggle switch, you could disable overdrive, but keep the lock-up if you wanted to.

 

That is great information. Looks like I will be hitting the junk yards for a 518 and using the vacuum and oil pressure switches trick. I had run across that transmissioncenter web page but did not drill down far enough to find the swap page.

Thanks for all the help, I'll let you know how it goes.

 

I'm thinking about doing the same swap behind a 440. Let me know how it goes.