Good Afternoon, I am new to this forum and am looking for some technical assistance. I have a 2002 Chevrolet Impala and have installed an engine and transmission from a 2003 Chevrolet Venture. The install was pretty straightforward and I connected the 2002 wiring to all of the sensors and controls on the 2003 engine and transmission with the exception of the switch on the shift lever. The 2002 Impala does not use an external "neutral safety" on the transmission so I just took the switch off.
The initial start up was good and everything seemed to work normally and I topped off all of the fluids and charged the A/C. When I test drove it, I got a check engine light pretty quick and the shifts were very harsh and it felt like the torque converter was locked up. The scan tool revealed that the Transmission Pressure Solenoid was not being controlled and that the Torque Converter Solenoid was full on.
I did some initial searching on the web and uncovered a Facebook post that seemed to indicate that you could make this kind of exchange work if you spliced in the external switch into the 20 pin connector.

Unfortunately the post didn't give any information beyond the statement that it was possible.

Anyone out there with any experience with this? Thoughts/guidance??

Thanks
Mark

That'* a good one. You might have to hold a couple of wiring diagrams side-by side to get this resolved.

I assume this was the same engine in both?

What were the problems with the Impala'* old engine and transmission?

Did the Venture engine and transmission run perfectly before they were moved to the Impala?

There is quite a history for the Impala. It belonged to one of my neighbors who bought it new and kept it in the garage most of its life. The owner passed away and left it to his granddaughter who is a teenage young woman. The 3.4L engine had worked really well for the original owner for 130,000 miles, however the granddaughter overheated it in about 500 miles of driving and then didn't stop when it show that it was overheating. I would suspect that the 3.4L had the traditional intake gasket failure sometime in the 500 miles that the granddaughter drove the impala, however she probably didn't know to check the fluids regularly. When she drove it home, I could see the smoke rising from my back porch for hours so she must have gotten it really hot on the drive home. It sat for about 4 years after that and I saw it under the parking port when I mowed my grass. They put the house up for sale last year so I decided to ask about the impala as my son was getting near the age where he would need to learn how to drive. They let me have the impala for $500 and I had AAA tow it over to my garage where I started to take a close look at it. She really cooked it when she drove it how so I decided that the best way to approach was either a complete rebuild or a replacement.

As I examined the cost for each of these pathways, a 2003 Venture was offered on the auction block of my local insurance auction house. The Venture had 30,000 miles on it and had been hit in the cargo door on the drivers side. It had really damaged the uni-body so it was not salvageable for repair, however the engine and transaxle worked perfectly. I bought it for $400 and had AAA tow it to my garage where I pulled the Engine and Transaxle and salvaged the rest of the Venture.

The 3.4L and 4T65E from the Venture was nearly identical to the 3.4L and 4T65E that I pulled from the Impala. The only major difference was that the transaxle from th the venture had an external "range switch" and the Impala did not.

Anyway, you are correct in your statement that I will need to compare the wiring diagrams for each and see why the new transaxle is not working like it did in the Venture.

I could really use the wiring diagrams if anyone on this forum has them. I am sure that this can be overcome, I just need to tease out the differences in the internal wiring of these 2 transaxles and it should work great.

Thanks in advance for anyone that is able to offer assistance.

Regards
Mark

Not all 4T65-E'* are the same. Depending on the platform in which it came out of, it may have a taller or shorter FD ratio in which your car is programmed for. This will have an effect on when your trans shifts gears.