Dodge RamCharger Central banner
1 - 11 of 11 Posts

·
Registered
Joined
·
59 Posts
Discussion Starter · #1 ·
How do you hook up the OD when going from a 727 to 518 transmission in a 87 RC?

Just add a button to turn on the OD? Will it kick out of OD automatically when downshifting or must you manually turn it off?

Thanks,

John
 

·
Premium Member
Joined
·
4,879 Posts
Yes. Wire in the OD button. Leave it off, it will not shift into OD. Turn it on, it will shift into OD by itself, and downshift to drive if you get on it, or it will disengage when coming to a stop.

The caviat--you need a 46RH A518, not the 46RE. The 46RH is still internally hydraulically controlled (except the OD), the 46RE needs a matching engine managment computer to tell it when to shift.

-SM
 

·
Registered
Joined
·
100 Posts
I've know a few people to do this and was always told that you must turn the OD off at the switch or it wont come out of OD and burn it up, when slowing to a stop and than starting again.
 

·
Registered
Joined
·
8,924 Posts
Try doing a search, this topic has been covered many times.
 

·
Registered
Joined
·
59 Posts
Discussion Starter · #5 ·
Tried the search, found nothing on wiring up the OD (could be my limited computer skills!)

Also, is the 518 the same length as the 727 or do I need to move crossmembers and shorten/lengthen driveshafts?
 

·
Registered
Joined
·
8,924 Posts
I guess that they are pretty close to the same length. But you still need a different crossmember.
 

·
Premium Member
Joined
·
4,879 Posts
Different crossmember, and I believe the 518 is longer as well.

Mr Jones: what disengages the OD on the 518 in the newer rams? You don't have to turn the button to 'off' on them....

-S/6
 

·
Registered
Joined
·
100 Posts
The computer controls all the shifting on the new rams, or at least all 96 and up. but i can see how it would work on the older 518's. as for the cross member i'm almost positive you dont need to change the main cross member tat connects to the frame, just the rear support plate that bolts to the T-case and the cross member. when i put a 727 out of a donar 85 into my 90 the rear plate, the T-case linkage, and the driveshafts were all that needed to be changed.
 

·
Registered
Joined
·
100 Posts
The computer controls all the shifting on the new rams, or at least all 96 and up. but i can see how it would work on the older 518's. as for the cross member i'm almost positive you dont need to change the main cross member tat connects to the frame, just the rear support plate that bolts to the T-case and the cross member. when i put a 727 out of a donar 85 into my 90 the rear plate, the T-case linkage, and the driveshafts were all that needed to be changed.
 

·
Registered
Joined
·
736 Posts
Its advisable to get a 95 or older A518 for the simplicity of OBD1, it dosnt control the trans. The oD will kik down automatically when govoner pressure raises.
You will have to have your driveshaft shortened and if you have a lot of lift that can hurt.

Good luck
 
1 - 11 of 11 Posts
Top