Transmission code p029

NORMAN E DALE

MEMBER
1994 CADILLAC ELDORADO
V8
FWD
AUTOMATIC

I just changed the trans. In my 1994 cadillac eldorado. I put in a trans. From a 1994 deville now is when iam getting the code p029. I checked the solinoids and they checked ok. I didn't clear the codes from the old trans, will that give me a problem? Both transmissions are 4t80e but the deville has 19 pins and the eldorado has 14 pins, are they wired different? Both cars where with a y. The trans doesn't shift to 3rd gear and let off throttle and goes freewheel.

2 Replies

FACTORYJACK

MECHANIC
4,159 POSTS

The codes will not remain from the old trans, and they should be identical if they are from the same VIN. The connector should also be the same, it is a 20 pin connector, with 14 wires, and they should be wired the same. You said you checked the solenoids, how was that accomplished? A few things need to be considered in doing this, one is that the solenoids mechanically function, it needs to be verified that they can be turned on and off(i.E. Are getting signal from PCM). The solenoids are the same, so one could be switched with the other to see if the code/symptom changes. The lower valve body has to be removed to change them. Look closely at the little black square between the solenoids. Early design had no means of retaining that filter, and eventually it could push out and break the solenoid. A new solenoid kit would include a bracket and longer bolt to upgrade and prevent that from reoccurring. It could be that the base of the solenoid is cracked, and it is not able to perform it's hydraulic function correctly.

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Sunday, November 14th, 2010 AT 12:48 AM

NORMAN E DALE

MEMBER
2 POSTS

Thank you for your quick response. Are the wires the wires hooked up to the same pins in the plug? The filter between the solinoids has a bracket holding it in place and is secure. There are 2 switches on the top side of the valve body and the valve has a painted date on it the year 2000. I beleive that is where i'm getting the extra wires from. I removed the pan off the transmission I removed and there is only one switch on the top of the valve body and of course less wires going to the plug. The valve body has the same part number on it as the one out of the eldorado. Both transmissions were the same vin with a y and 4t80e. The solenoids on the deville trans. Are different one has the plug on the side and the other is on the bottom for clearance for the for one of the switches that is mounted on top of the valve body. The trans out of the eldorado does not have that switch. Could this problem i'm having be the computer? I had a simular problem when the trans. Went out and put lots of junk into the pan. Thank you again.

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Sunday, November 14th, 2010 AT 5:07 AM