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Need help ID'ing and procuring trans for neighbor

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1K views 14 replies 3 participants last post by  Shorts  
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#1 ·
Need help ID\'ing and procuring trans for neighbor

My neighbor is in a bit of a bind. He owns an '88 Chevy 1/2 ton standard cab, short bed. It has a 305V8 and a 3-spd automatic. He blew his trans and is in need of a new one. He was told it was a TH375, and proceeded to purchase one from a local company. He handed in his core up front (big no-no) and waited for his replacement trans. Firstime they shipped a Th400, second and third time, they shipped a TH375 but without the electronic speed sensor tailshaft, so it won't work. They ended up giving him $120 for his core because now they can't seem to find it. He came to me after the fact and I'm trying to help him out (he is in a wheelchair to boot, was in a major motorcycle accident 3 months ago).

So, a couple questions. I've never heard of a TH375. Is there such a thing? What's the dealio with the speed sensor, should he have salvaged some parts off his core to make it work? Recommend hitting the junkyard to get those essential parts? Can a new trans be purchased with required tailshaft to work in his truck (he can't seem to find one locally yet). Can a th350 or th400 be put in and if so, what year/vehicle/configuration will work with his 88? All in all, he realizes he should have just had it rebuilt, but will do just about anything to get a new one before winter arrives. Any help you guys can give me is greatly appreciated!

Thanks,
Chris
 
#2 ·
Re: Need help ID\'ing and procuring trans for neighbor

an '88 i'm thinking should have a 700r4, which is an auto...hmm, that brings to mind the 4l60, which was in the early 90s trucks. then in 94 the 4l60e came into play.

someone else can chime in here that knows about blowin' trannies
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lol sorry....now mine is going to go out with 149k
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....knock on wood!
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#3 ·
Re: Need help ID\'ing and procuring trans for neighbor

I wonder if I can do some investigative work on what was truly in his truck. He says it was a TH375, but that's only because that's what the store told him it was. Anyways, I wonder if I could find out through the VIN # or the codes in the door column or glove box??

Chris
 
#5 ·
Re: Need help ID\'ing and procuring trans for neighbor

here's a tranny ID page. on that same website is a lot of info on how to decode fender tags and such. if you can't find the rpos you need, just search the internet for "gm rpo codes" and variations of that. usually the search will bring up muscle cars and such, but the codes all mean the same thing no matter what vehicle make/model its in.

http://www.nastyz28.com/transid.html
 
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#8 ·
Re: Need help ID\'ing and procuring trans for neighbor

that is the less desireable "metric" trans, a 700r4 is pretty much a direct replacement for the trans. dont quote me, but I think you can still use the same driveshaft. get rid of that POS. for a more reliable 700 (even if you have to get a shaft)
any 700 will fit from 91(better pumps) to 94, it still has the correct harness for the lockout converter and the VSS (vehicle speed sensor) dont get a 4l60e or 4l80e, cause they are computer controlled, not controlled by a kick down cable. I think those run from model years mid 95 and up. You will want the heavier torque converter also (about $250) With the core I think you can shop around at a reputable trans shop and get a rebuilt 700 for about $800. just make sure you tell the trans shop the tail has to be from model years 88-94 for the speed sensor,,,oh, and take off all the harnesses and sensors.
 
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#9 ·
Re: Need help ID\'ing and procuring trans for neighbor

BTW, it's an 88 4x2 Scottsdale. I just got back from his house. I grabbed the VIN and all the RPO codes to see what it came with stock. Here they are...

A01 A52 B74 B84 C5G C95 D45 E63 F59 GMC GU4 J50 K99 L03 MX1 M40 NA5 N41 N67 SLM UK4 U37 U73 VB3 VG3 VK3 V73 XEV YD3 YD5 YD6 YEV ZEV ZY1 Z53 Z62 18U 6WN 7WN 82C 82I

I'll check out the page you reference, but isn't the RPO codes different between cars/trucks?

Any help is appreciated...

Chris
 
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#10 ·
Re: Need help ID\'ing and procuring trans for neighbor

I checked a couple websites and here's what I found for the RPO Codes specific to the trans...

MX1 : MERCHANDISED, TRANS, AUTO PROVISIONS
M40 : TRANSMISSION, AUTO 3 SPD, TORQUE CONV VAR 1

Anyone know what these two really mean? Like does it mean TH350, TH375 or TH400?

Thanks,
Chris
 
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#11 ·
Re: Need help ID\'ing and procuring trans for neighbor

I read on the off-road.com website (Jeep Tech section about GM trannies) that the 700R4 was built from 1982 - 1990, and was replaced by the 4l60 or something after that (the electronic version). Would I be better off finding him a trans from a truck, or a car, or does it not matter? My local junkyard sells trans for $70 if I pull it. Haven't looked into a rebuilt one locally yet though.

Chris
 
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#12 ·
Re: Need help ID\'ing and procuring trans for neighbor

they are the same, you want a 90-94 a 4l60 is the same as a 700r4 they modified it thruogh the years, but for your aplication, 90-94 will be the best. After that you need a $300 computer and harness (available from GM) to controll the trans (thats the 4l60E)
 
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