Rear overdrive unit interchange a500-a518-a618

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rustytoolss

rustytoolss

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Just looking for some information. Will the rear overdrive unit of an later model a518/46re (say 1997 or so), bolt onto an earlier model a500r/42rh (say 1988 or so) and work correctly ?
What about the overdrive unit from an a618/47re...will it bolt onto an early a500/42rh.
Only asking because the later a518 and a618 overdrive units were built with update/stronger parts...from what I have read ...could be wrong about that ???
 
Short answer, no. RH units are hydraulically controlled, there's a governor in the O/D unit that feeds back into the main case through 2 steel tubes. RE units don't have this, their shifting, etc is controlled by the computer.
 
so you could only swap OD unit between a500rh to an a518 rh....and between an a500re to an a518re....sound right ?
 
As far as I know (or have done), yes, the O/D units will swap within their respective species. I've changed 4wd's to a 2wd, (both RH and RE) with no problems. The only differences I've noticed are the number of clutch discs, the H/D applications had more, done by using different thickness pressure plates.
 
RE to RE and RH to RH only . if changing RE housings between 47RE and 48 RE change the park rod with the housing they are different on the rear lug dia. for park pawl.
 
do you know...are the a518 OD units built stronger (clutches, planetarys) than the A500s ? Also do you know when the OD units got the 15 degree planetary gear sets ?
 
The a500 and 518 od sections are the same other than the 518 units have more frictions per pack for more torque load, the od units were updated to 15 deg for the 1994 season,
Lon
 
Anyone want to buy a nice 518 with 618 guts? I have an electronic one I might sell....Converter included.
 
rustytoolss said:
do you know...are the a518 OD units built stronger (clutches, planetarys) than the A500s ? Also do you know when the OD units got the 15 degree planetary gear sets ?
Click to expand...
A500 planetary set changed at the factory in 1996. Used from 1996 to 2004(15 degree upgrade).
A518 planetary set changed at the factory in 1994. Used from 1994 - on (15 degree upgrade).
The planetary set is the same for both the A500 and the A518.
As I mentioned in a previous post on this subject, the Factory made the change as the 15 degree planetary is stronger than the 22.5 gear set.
The friction plates in the overdrive section, are the same, no matter if its off a A500 or A518. The A518 could have 3-5 Overdrive frictions and 8-10 Overdrive direct frictions. The A500 could use 2-4 Overdrive frictions, and 5-8 Overdrive direct frictions.
 
transman said:
A500 planetary set changed at the factory in 1996. Used from 1996 to 2004(15 degree upgrade).
A518 planetary set changed at the factory in 1994. Used from 1994 - on (15 degree upgrade).
The planetary set is the same for both the A500 and the A518.
As I mentioned in a previous post on this subject, the Factory made the change as the 15 degree planetary is stronger than the 22.5 gear set.
The friction plates in the overdrive section, are the same, no matter if its off a A500 or A518. The A518 could have 3-5 Overdrive frictions and 8-10 Overdrive direct frictions. The A500 could use 2-4 Overdrive frictions, and 5-8 Overdrive direct frictions.
Click to expand...
Just reopening this thread... I have one 42rh and a 46rh... an I will rebuild the 42 using parts of the 46rh that are better (ex OD unit) and others which I would appreciate for tips ... I'm buying a a500 master kit... but I think it will not come with the correct number of disks for 46 OD for example.. the disks from both are the same size and changes quantities? If I buy a518 disks I could use on A500?
 
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