My dad and my friend Chris and I went to the wrecking yard today and got another transmission for my 77 C10. A 4L60 out of a 1990 GMC 3/4 ton van. I'm trying to figure out the code numbers (3BWM434211) I know the "3" is for 1993 and the "M" is for 4L60, but I'm not sure about the "BW" part.
I got it complete with a TV cable, torc converter, Dip stick and tube. But the best part was the sticker on the bell housing. It was a GM re-manufactured transmission.
$145.00
The M is just a code for GM transmission, all of them have an M followed my other letters and #'s and some of them even repeat so I usually don't put much into those. You're right, it is a 93 transmission which is rare for the 700r4, so at least you know you have the latest greatest 700r4. As far as the BWM that is just the Service wiring code that tells what kind of vehicle comes in originally, but the wiring harness can be or could have been changed. It also usually tells what size engine it came behind by the wiring code. For example, Could have been a 305 TPI Car, 350 TBI Truck, 4.3 TBI, 350 Carbed, etc etc, I don't have my code book handy to tell you exactly, and it being that late model, my book might not even have the code. But you know what it came out of and probably worked fine in that vehicle. The sticker tells you about all you need to know along with what you pulled it out of. It's a GM Warranty Replacement so it's probably coded to be for any GM TBI Truck from 87-92 and early 93's or the very few models left over that got the NON E transmissions. I'm really not even sure what got the 93 700r4/4L60 without the E. It might have been I6 or V6 Parcel Vans, but to the best of my knowledge, Standard Pickups, S Series Pick Ups, G Series Vans like you got this out of, and the Astro Van series all got the E transmissions in 93. I just know the 93 700r4/4L60 is rare. I've seen one other and that's it. I've seen plenty and have 2 of the 92's which chances are, the same as the 93 since there are no noted changes to a 93.
At any rate, hopefully it works good, and if it doesn't, it should be a good core to build and have all the latest 700r4/4L60 updates in it.