i have a 95 6.5 diesel with a 4l80e trans that i put in a 87 pick-up i need a pcm for this van to control the tranny i have found that the pcm is specific to the vin code 1GBHG31YXSF21858 any one know how i can get a pcm (cheap around $100 or so) that will plug into the van harness??

I'm doing the same swap . They are TCM's and the number is 16196390 . I found 2 on Ebay over the years . They do pop up from time to time . You have the Y engine , the TCM only controls the 4L80E as there is no DS4 injection pump just the DB2 . The TCM is fairly easy to spot , there are no color markings , like the blue or red connectors , where the wire harness plugs in . Don't get the early TCM from 91 - 93 as they made some changes in 94 .

i have another dumb question I want to run a std tach (not a diesel, alt or flywheel pick-up) i was wondering if someone or i can make a signal amplifier (converter) to use the engine speed sensor (back of engine) to run the tachometer the reson i want to do this is one budget and two i have several gas tachs laying around i have tried just pluging tach signal wire into ecm harness at the engine speed sensor pin i get some movment at high rpm but the sensor signal is to week to operate tach