I agreed to build a trans for my sons friend. His is still working and I told him I could build a core I have here and just swap it out for him in a few hours so he could still have a way to get to work. He has a 2007 Silverado and later I found out the core I have is an 05 Silverado. I’ve come to the conclusion that it will not be a direct swap. I’ve tried to source an 07 core with no luck. So my question is, what’s different and what will I need to change to make it compatible? I think the 07’s have a purple plug and the 05 has a green plug. I think the pump has a sensor in it on the 2007. So change the pump, change the harness. Whatelse?

 

Man those few years in there are some weird ones. 05 is when they started to integrate ISS, reluctor on the input shaft or spot for the reluctor but didnt machine it in yet, different stator for said input shaft, ect. Its really going to depend on what the build date is on it and where the factory was at during that date on his specific unit. I do not think there is SPECIFIC information regarding this either I.E Nov 2006 build it had this that and this. Then Feb 2007 they started to change to this and that. At least I havent seen it. There is information regarding the changes in parts as far as what to potentially look for when you break it open, but you wont know exactly whats in it until you break it open. Hope that makes sense?

Honestly, I hate to say this but without breaking his open to see what specifically is inside it I think you will get yourself into a jam with a 2007 unit trying to get ahead of the game. The last unit I did was out of a 2007 GMC Envoy with a 5.3 but it had 2006 stampings on the input drum which would be an earlier unit. But if I remember if you looked up parts for a 2007 a few parts changed than what it actually had in it. Also you mentioned the plug, his "2007" had a green plug.
Fortunately for me it was the cleanest 150k mile unit I have ever seen so I didnt have to change any hard parts except the reaction hub. But it would of been interesting if I had to.

As always, someone smarter than I please correct me but this is my opinion.

 

First determine if the core you have uses a push in seal in case around pump. If it does you have it made just get a later pump and input drum or shaft along with harness. 07 up on pump and drum and 07 08 harness
If not you have a couple more options. One he could tune vehicle to not need the ISS, or if you have a lathe, you could just get the late pump and machine the groove in it for the pump Oring seal.
The 07 and 08 units can be hard to source which is why I give these options

 

Really the only notable change that matters for swap-ability of complete built units is the Input speed sensor.
In your case you would need:

Input shaft speed sensor stator (your 05 is VERY unlikely to have this...but there are some odd ducks that do have this and there's just a plug in the sensor hole)
Input shaft with speed sensor tone ring
speed sensor itself
internal harness (extra pins for speed sensor)
that's it

If you've done pump modifications (such as a boost valve)
Be cautious of the valve length. The Input speed sensor stator halves used a shorter boost valve sleeve. Sonnax calls it "LB1" for the early (non ISS) long units and they call it "LB2" for the shorter later units intended for ISS stators.

The pump body should be the same cast # and you can bolt it right to the stator for speed sensor
If you're using the 05 pump body and case...no need to worry about any seal issues.

The reason the stator and input shaft MUST be matched is obviously for the speed sensor to read...but also the sealing ring height was changed. They were moved to make room for the ISS tone ring. So just for any builds in the future be cautious about mixing and matching input shafts and stators in this 05-09 ballpark of years. You need to make sure input and stator match or you'll have big cross leaks and leak to exhaust etc. No fun.

I would recommend against tuning out the ISS
I've seen this tried before...sometimes it seems to work without issue but I've also seen it cause a whole mess. Tough to diag. Weird lockup and funky shift commands. etc
You may get away with it, but there's a chance it becomes a headache.

 

Man the dude told me (I swear more than once) that he has an 07. Now he said it’s an 06. I’m gonna look at the plug on his trans and see if it’s purple. If it’s not, maybe I’ll be in luck.

 

Lets hope its green!

 

Pre 2007-2008 will be White/ Cream Body Case Connector.




2007-2008 will be Black.



2009+ will be Light Blue.

 

So is it possible to build a trans that can work with both gen3 and gen 4 PCM's ?

 

you the man. I got up under the truck yesterday, the plug is the same color as the core I have. The are both like the first one. Which look grey and a green insert. So I should be good to go? Truck is an 06. I verified that. Trans is 05.

 

Sounds Good!

 

I appreciate it! I’m starting on it this weekend. Worse comes to worse, I’ll be doing the r&r, when I have it out and I think it different, then I’ll just transfer what I can over to his original and just build it. Be a pain in the ***, but it is what it is.