47rh vs A-518

[dzlpwr]

Got a question for you guys that work on chrysler trannies. Is the 47rh similar to an A-518 except it has a valve body with the lockup passages and valves? Also, if it is, are the lock-up signal valves and oil passages also located in the front support? Is the lockup activated by gov and mod pressure or is it electronic? I have been trained in Allison Automatic transmissions and was just wondering if maybe chrysler was setup the same way. I can get ahold of a 47rh valve body and TC but not a front support. Thanks for any help, Bryan

 

[BushWakr - RIP]

Bryan,



Don't take this as the gospel but..... I believe the rh is "h" as in hydraulic, and the re is "e" as in electronic.



Also, if I remember a thread on this a while back the 727 was upgraded to the A518, which was upgraded to the 47rh lock-up, then came the 47re lock-up. I THINK that was the sequence of builds.

Lastly as I recall the US has a different "label"... . here it's the A518 in terms of order code on my build sheet... . in the US it's different, but I can't remember what it was. . maybe the 618????



Bob.

 

[PPeters]

Got a copy of my Vehicle Information Plus Summary Report from local dealer after giving them my VIN number. transmission spec on sheet is as follows:



Options Descriptions

DGB Transmission - 4-Speed Automatic

DGRS Transmission - 4-Spd. Automatic, 46RH



FWIW



Pat

 

[Power Wagon]

The terms "518" and "47RH" are marketing names for products.



You will find there are athoritative documents that call the 47RH a 618. I believe that the 47RH was actually called the 618 during development, but once produced marketed under a new naming convention. All chrysler automatics had a letter + 3 digit naming scheme, and all were changed to digit + letters scheme, or, at least the ones in current production. All those not in current production retained their "old" designations.



From everything I have been able to gather, it is possible to make a 518 into a 47RH by the addition of a lockup converter, some parts changes in the front of the transmission (input shafts, front pump, etc) and valve body changes.



I have been told by at least 2 supposedly knowledgeable people that adding the lockup is a reasonably simple procedure for a 518.



Thus, I would believe that the 518 and 47RH have only minor differences and are really the same thing overall.

 

[Joe G.]

A 47RH lockup and OD are controlled by solenoid valves. The solenoids are part of the valve body. I don't know how a 518 valve body could be converted to control a lockup torque convertor without a provision for the solenoid. I have no idea if a 47RH valve body would fit the 518, but I would not bet on it because there would have to be a passage for the lockup pressure to get to the torque convertor. If the transmissions will bolt up the same way a 47RH could be substituted for a 518. A manual switch would have to be installed to control the lockup since there is no automatic electronic way to do it on a '93 truck. See "mystery switch" on the 2nd gen 12 valve forum. The solenoid setup is different on the 47RE because the governor is electronic.

 

[PPeters]

Anyone have any idea why my sheet calls the transmission a 46RH



Pat

 

[Power Wagon]

46RH = Non-lockup 518



47RH = lockup 518 OR 618



I have seen all these designations used.

 

[Joe G.]

My '95 service manual has three transmissions:



42RH - light duty for 1/2 ton V6 or V8 gas



46RH - medium duty for 3/4 and 1 ton V8 gas



47RH - heavy duty for 3/4 and 1 ton diesel and V10



From this I would assume that the 4 indicates a lockup TC since all '95s have that. The 2,6, and 7 is the duty rating. The R is rear wheel drive. The H is hydraulic governor.



The '96 thru '02 have the same transmissions except that the H is replaced by E for electronic governor.



I have not seen the service manual for a '93 so I can't say for sure what it has so my assumption is that the 46RH is not used in it. I have seen the '93 transmission referred to as a 37RH. If the transmission used in the '93 is called a 46RH and does not have a lockup TC it's a different animal.

 

[Speedo]

Allisons

If you are asking if it is the same situation going from a 518

to a 47rh as it is going from say an MT 643 to an MT 653 no it

isn't the same situation as far as I know.



Gus

 

[DPKetchum]

Had a 1990 D350 srw with 360 gas i bought new. Had some problems with O/d light/switch not working at times. ANYHOW back then the tech found off the jump it had a code for no lockup. He went hunting this of course and realized that the lockup solenoid was missing from valve body. Said the space etc was there for it but solonoid was wasn't. Then realized truck was a non lockup by design. You could reset code and as soon as started it would set again. Comments were that it was designed for a lock up converter just missing key elements such as converter and solenoid. Years later a tech doing some work on it said YOUR truck has a lockup problem. Keeps setting a code for it. I had to explain that all 250/350 etc then had no lockup etc.