93 k1500 4l60e (SOLVED!)

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zty7

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I have a 93 Silverado I bought a few months back 178,000 miles. When bought it had small electrical issues like the heater would only turn on windshield defroster (no vents) only one stereo speaker worked and some interior lights didn't work. A short while ago I had a very small offroad accident were I skimmed a small tree enough to peel the front right fender back (it was already loose and smashed.) The moment I hit the tree I noticed a few electrical problems occurred, the heater quit working completely, the 4x4 light went off and speedo stopped working. next day I try to drive it and the trans only goes into 1st gear when in D overdrive, I can manually shift to second gear (2). That's it. I believed my trans problems were all electrical because of the fact that the trans shifted perfectly until the moment I hit the tree and that's when some electrical problems happened. This morning I took out the ECM, and unplugged every electrical connector behind the glove box and I did find some corrosion on some of the terminals. I cleaned everything up made sure all was plugged back in and when I drove it for the first time I put it in D overdrive and it shifted from 1 to 2 on its own no slip (good sign) but when it tried shifting to 3rd it slipped out of gear completely and went back to how it was before manual shifting to second without 3rd or 4th. all fuses double checked none are blown. was thinking just buying new ecm, any gmt400 gurus know what could fix it? Yes I saw where a couple people posted that to fix no 3rd or 4th replaced the 3-4 clutch pack but just didn't know if an impact would only cause that clutch to wear out instantly. I guess since I was in 3rd or 4th gear when I hit the tree then it could have rubbed the clutch hard?
 
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zty7

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I have a 93 Silverado I bought a few months back 178,000 miles. When bought it had small electrical issues like the heater would only turn on windshield defroster (no vents) only one stereo speaker worked and some interior lights didn't work. A short while ago I had a very small offroad accident were I skimmed a small tree enough to peel the front right fender back (it was already loose and smashed.) The moment I hit the tree I noticed a few electrical problems occurred, the heater quit working completely, the 4x4 light went off and speedo stopped working. next day I try to drive it and the trans only goes into 1st gear when in D overdrive, I can manually shift to second gear (2). That's it. I believed my trans problems were all electrical because of the fact that the trans shifted perfectly until the moment I hit the tree and that's when some electrical problems happened. This morning I took out the ECM, and unplugged every electrical connector behind the glove box and I did find some corrosion on some of the terminals. I cleaned everything up made sure all was plugged back in and when I drove it for the first time I put it in D overdrive and it shifted from 1 to 2 on its own no slip (good sign) but when it tried shifting to 3rd it slipped out of gear completely and went back to how it was before manual shifting to second without 3rd or 4th. all fuses double checked none are blown. was thinking just buying new ecm, any gmt400 gurus know what could fix it? Yes I saw where a couple people posted that to fix no 3rd or 4th replaced the 3-4 clutch pack but just didn't know if an impact would only cause that clutch to wear out instantly. I guess since I was in 3rd or 4th gear when I hit the tree then it could have rubbed the clutch hard?
The problem is fixed and it was as simple as it can get. It was one two wired connector under the driver side dash that had a little corrosion on it, cleaned it with PB blaster and trans shifts perfectly in all gears, speedo works and heater works again. One little wire can stop this truck from being drivable. To anyone that has the same issue as I had where it doesn't come out of first in drive, your problem could be a number of things like the vehicle speed sensor on the back of the trans, the vehicle speed control.module behind the glove box(little white box with two connectors) maybe a corroded terminal on ecu, or.maybe something as simple as mine like one wire being corroded. If you have these symptoms there's a 90% chance there's nothing wrong with your trans, probably just a loose or corrosive wire in.the system causing problems. Considering my specific 93 k1500 was a flood vehicle I should have expected some corrosion. Good luck
 

Maddhatter

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Do u have any pics of this 2wire connector?...I have a similar problem with the shifting but didn't hit any trees.my truck is a 94 and I parked at a u pull it yard and when I left it would not go into second unless I lifted off the gas then it would shift..I stopped for gas before hitting the highway and it did the same first to second then again from second to third..id like to rule out electrical before dropping trans..the fluid is at the level but looks burnt and the trans pump was whining when I bought it 2 weeks ago ..so I think its the clutches ..I know nothing about transmissions but have been a mechanic for 28 years....just drop and swap
 
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zty7

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Do u have any pics of this 2wire connector?...I have a similar problem with the shifting but didn't hit any trees.my truck is a 94 and I parked at a u pull it yard and when I left it would not go into second unless I lifted off the gas then it would shift..I stopped for gas before hitting the highway and it did the same first to second then again from second to third..id like to rule out electrical before dropping trans..the fluid is at the level but looks burnt and the trans pump was whining when I bought it 2 weeks ago ..so I think its the clutches ..I know nothing about transmissions but have been a mechanic for 28 years....just drop and swap
If your problem was electrical, it wouldn't shift into high gear at all. Also if the fluid looks burnt and trans acts like its slipping I can almost guarantee your clutch plates are bad but dont quote me. You could try dumping all trans fluid out, flush all fluid replace trans filter and replace all fluid. That was the solution for an old dodge I had maybe your truck just grinded the clutch plates at one point? Sounds more serious than my issue. Here is that connector though. Good luck. PS your trans pump whining was probably her screaming at you to fix her, might be reason why your clutch plates got burnt in the first place


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Maddhatter

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K thanx ..im leaning tward the burnt up side of things...but ill check that plug anyways...I have had 4 of these trucks and had to have the trans built on every one...just my luck I guess
 
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