Non lockup 518 to lockup, possible?
 

Just thinkin, but there has been much debate over the fact that the 94+ is an A518 or A618 and to weather or not its technicaly the same tranny in the 1st gen. SOOO.... is it possible to CONVERT, a non lockup A518 in a first gen, to a lockup A518 found in the second gen???
If they are really the same tranny, it should be able to be done with second generation parts, RIGHT?

What is REALLY the difference?? I dont understand lockup transmissions and how thats all done, so, maybe im just missing something.

You'd have to switch the front main bearing carrier as it has the additional plumbing for the lock-up converter. You'd also have to switch the valvebody for one with the TC lock-up control.


As to weather there's differences in the transmission case to support the lock-up converter, I'm not sure, but I don't think so.

The FSM and '93 dealer service manual shows a typical hydraulic schematic for the 32RH,36RH,37RH, and 46RH (A518). Said schematic includes the lock-up converter controls.

I believe the 2nd gen unit has beefier clutches/drums and a few more spider gears.


I'm hoping those who know better will speak up. [redface]

I have not done this, but I have used parts from the A518 for 47RH's
You would need a lockup input shaft, a reaction shaft support (this is the part that the input shaft goes through, valve body to match, lockup converter and the engine bell housing adapter to match, and a new 3 wire connector for the valve body connector.

Modify the trans mount and maybe the drive shaft because the trans is going to move back about an inch.

Dave is pretty close on the difference, but the main difference between the A518 and the 47Rx's is the front planet. 518's had 4 pinion aluminum carriers, 47RH's had 5 pinion aluminum ones and 47RE's had 5 pinion steel ones, those are the ones you actually want to run. The rear band is a major difference between the 518 and the 47. 518's run a singe wrap band with a larger diameter rear piston than the 47's. They run a smaller piston with a double wrap band.

There's other differences, but that starts to pretty deep and unless you've worked on them and know explaining it here will confuse you further.

Just a note, I've seen 47RH cases used to build non-lockup transmissions so there is no reason you can't build a lockup 518.

Case is the same, ditto the pump housing, you need a lockup input shaft, reaction shaft support, and valve body. The problem is the first gen adapter is an 1" too short to accommodate a lockup converter, so you have to use a 2nd gen adapter (flywheel housing). No one makes a lockup converter for the 1st gen trucks, and they believe the market is too small to justify tooling up to make one. If you put a 47 in you still need the 2nd gen adapter, 47 has several upgrades compared to 518.

If you converted the 518 to a 47, could you then use the original starter motor, instead of a 2nd gen starter?

You can't just upgrade a 518 to a 47, the main difference in the case is the 47 has a double wrap L&R band, the 518 doesnt even have the case material there to bore the second anchor pin hole for the L&R band. I'd have to get my engineering change literature out to double check but I think 94 is when they changed the rear support, L&R drum and over running clutch, and they wont fit in the older trannies. The starter bolts to the flywheel housing (adapter), which tranny you have doesn't matter. You can upgrade to the the steel front carrier, but the carrier has to be resplined to fit 1st gen output shafts, spline pitch changed for the 94 MY. In 2002 I built a 727 for an 84 dodge 4x4 I had, I used 48re parts, the complete plannetary set, and the input shaft, reaction shaft support, 5 plate front clutch housing and the nescessary matching rear clutch retainer. The 84 was non lockup so I ordered a dummy lockup converter (non lockup converter with lockup splines). It works good, still going for the 3rd owner since then.