Auto to Manual Trans Swap

[Garynick]

I am a true newbie to much of the OBD1 coding and prom changes. I have been working on and tuning cars and bikes for several decades now, just haven't had the need to get an closer within the ECM other than changing harnesses, or merging a few harnesses. Wiring and sensors don't intimate me much, the software is another animal!
Currently I'm going through a '89 GMC K1500 with a stock 350. Truck originally had an automatic transmission, and transfer case. Now that same truck has a manual 5 speed with the transfer case. I'm under the impression most everything can remain the same, other than a signal to the ECM if the truck is in Park or Neutral, and the TCC circuitry. Will it be a simple matter of installing a pre-programed chip into this ECM, and cleaning up some of the wiring, or is there a bit more involved? BTW, the ECM in this truck is a 16125851 ANLW.
Thanks in advance to whatever direction I may be guided!

[dave w]

I was not able to find ECM 16125851 in the gearhead-efi OBD1 information.

I was able to find ANLW listed in the 1227747 in the gearhead-efi OBD1 information: http://www.gearhead-efi.com/Fuel-Inj...Information-42

The above link lists a few chip codes for Manual Transmission.

dave w

[stew86MCSS396]

Looking at this pic at thirdgen.org it's the service no. that you need for the ECM. The link dave w provided, has schematics of the '7747. My understanding is for a manual transmission conversion use a manual bin and pin B10 park/neutral switch, you want it to think it's in gear at all times so the IAC logic is active.

[Garynick]

Thank you for the responses! You are correct, the Service NO is indeed 1227747 ANLW. I was grabbing other numbers from the ECM thinking they were needed.. I appreciate the access to the files, and the wiring diagrams match up with what I'm working with very well! By means of converting my ECU to a manual bin, I'll need to download and transfer those files into the PROM? Downloading shouldn't be an issue, but how do I go about transferring the bin to my existing ECU? Sorry to be asking such intro questions..
Garynick

[dave w]

The chip used in the 1227747 is electronically called a 2732 EPROM. which spelled out is Erasable Programmed Read Only Memory. The 2732 chip has several variants, mostly for the different voltages (25v, 21v, and 12.5v) used to program the chip.

The 2732 chip is designed to be erased with Ultra Violet (UV) light.

For a one time venture, it doesn't make sense, budget wise, to buy a UV eraser and chip programmer.

Several members have the equipment to erase and reprogram the 2732 chip.

Maybe post a message that your looking to get a chip reprogrammed? Possibly a member will reply by sending you a Private Message (PM) willing to help you out? Maybe search Ebay for a 1227747 Manual Chip: https://www.ebay.com/itm/Prom-Chip-A...8AAOSwf4BccDKe

dave w

[Garynick]

Thanks dave w! Well I've been learned something today! Anybody interested in programming the EPROM I am in need of? Let me know if you will need the current chip that is currently programmed for a 700R4 transmission, or if starting with another spared chip would be more agreeable. Thanks!