'92 a518 vss to '97 OBD2, compatible?

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fshd4it

fshd4it

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I'm in the planning stages of a magnum swap (since I'm stuck on the boat and can't do any hands-on car stuff), and I'm wondering if these two will play well together. My motor is a '97 5.9, complete with harness, computer, fuse box, etc...about everything under the hood of the truck came out with it. I'll be using a '92 a518 w/ lockup as I want to run my stock speedo with a cable, and I was going to use an inline VSS sender like the one below so the trans would still be controlled by the PCM. However, what I've found through web searches says that the cable adapter unit provides a small A/C voltage analog signal, while the 46re style uses a Hall Effect sensor for a digital signal. I'm just wondering if the OBD2 computer will work with what I'm afraid is an OBD1 specific transmission.

smp-sc108_bs_ml.jpg
 
Is your 92 harness a 3 pin plug at the trans? If so things are completely different. The later (6 or 8 pin connector I forget) trans is completely controlled by the PCM. "I think" my research has shown that you either need a later PCM and associated "stuff" or else a special manual valve body.

In other words you ain't gonna do it the way you are hoping. Go to the service manuals thread. There's a link there to a Russian site which you can dump into Google translate. You can get most any of the ATSG transmission manuals for free. Yes, they are pirate LOL

Free service manuals
 
The a518 I have is a 3 pin style, but my harness is for an electronic trans. The motor had a 46re attatched when I bought it, which I sold shortly thereafter. If the '97 computer won't work with my transmission, I was planning on changing the harness(es), PCM, and sensors over to OBD1. I understand the OBD2 is considered a superior system, but I'll be leaving this engine stock, and I figure this is still the easiest way to keep my speedo. I've got the ATSG manual at home, but thanks for the link. Gives me some new reading material.
 
What vehicle is this going into? A518 trans won't fit under an A-body without cutting the torsion bar crossmember and floor, if I recall correctly. Also, that older A518 is hydraulically controlled. I am pretty sure that speed sensor had no impact on trans operation for the A518 you still have. If you want a cable speedo hooked to that old A518, just install the regular old style speedometer drive housing and gear arrangement.
 
The whole package is going into a '77 D150 (basically a beater with a heater), as kind of a test mule of sorts, since this is my first foray into the magnum/fuel injected /overdrive field. I'm not ready to start chopping into my Duster, but there's a chance this drive train (or one like it) may end up in there. I want the trans o/d and lockup to be controlled by the pcm, but I'm not sure how changes between obd1/obd2, or the re/rh transmissions will determine what combination I need to use. I'm assuming the (correct) pcm uses a vss signal to control the a518, and I'm still searching for '92 schematics for more info. I could hook it all up stand-alone style, with pressure and vacuum switches, but that to me defeats part of the reason for keeping the computer.
 
the A518 you have is a 46RH that you can control with a kit from PATC
PATC 727 to 518 / 46RH Conversion Kit. Click here for 727 to 46RH swap wiring diagram - PATC
But it will not work with your pcm

Now what you can do is sell the 46rH and buy another 46r"E" there are two versions that will work with you computer. Both have a speed sender at the 8 o'clock position, this is what the pcm reads as well at the speedo sender. Here's where it gets tricky. The early 46r"E" had both. This will allow you to run the adapter in your first post. The Later 46r"E" had the speedo sender in the dif and will need to be converted in order to run the speedo in the over drive unit. I'm in the process of converting mine over from a later overdrive housing to a early 46r"E" tail so I can run my speedo as well have my pcm control my trans shifts and lockup torque converter , you can see it in my build thread below. So far cost hasn't been much. $50 for tail housing and gear drives from PATC for about $15-30 that is if all you can find is a later model 46r"E"
1965 Barracuda MMP

The picture below you can see the speed sender but no speedo drive hole "Later" 46RE
20170711_214834.jpg

This picture you can see both the speed sender and the speedo drive hole "Early" 46RE
20170711_214840.jpg


There is a third tail housing that has the speedo hole and the casting for the speed sensor but the casting is not drilled or tapped. I'm told its for a 2wd Diesel unit "Early" 46/47RE

Good luck with you build...
 
Now that is an option I never knew existed. Thankyou. I guess I always thought that an electronic transmission was just that...electronic. Now, of course, I'm wishing I hadn't gotten rid of the 46RE, but in my defense my plans for this motor have changed a lot since then. So you were able to use your original later output shaft with the earlier 2-hole tail housing? And the helical gears are there for the speedo pinion? Looks like I'm going shopping for another RE. Sorry for the slow response, I ended up reading your whole build post. Really cool stuff you're doing there. Thanks again.
 
Would it be any easier to find an ECM from a stick shift truck? Then you could just use the kit posted above in your 46RH, and let it do it's own thinking. I'm doing basically the same thing you are to an old 88 D150 long bed. My 5.9 Magnum motor, and every inch of underhood wiring and computer came from a 98 3500 5 spd truck. The ECM for a stick truck doesn't care what the transmission is doing as long as you have a speed sensor. My truck has an A998 or A999....whatever a lockup 904 was....lol. I'm probably gonna use it back and just beef it up. It's just an old beat around truck that hauls firewood, and stuff to the flea market.
 
That's another way to go, for sure. Finding one shouldn't be too tough, I'm on pretty good terms with the guys at a small local wrecking yard. They don't seem to mind looking up part numbers and applications for me. But they'll also sell me core transmissions for under $100, and if I'm gonna rebuild it anyway... The other nice thing about changing transmissions is that I could use the kit from PATC to put the RH behind an LA motor at some point. Wow. That's a lot of abbreviations.
 
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