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Discussion Starter #1
Does anybody know if a late model 4L80E can be swapped in a truck that has a early model 4L80E? I found a good deal on a rebuilt 4L80E with no core. I might just replace my trans and rebuild my current one as a spare. The truck is a 1993 C3500 2WD.
 

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The main differences are-
 
1. The TCM/PCM is different 94-up, see info.
2. The 95-up shift shaft is different.
The early short shaft can be swapped.
3. Cooler lines are different, need to make adjustment.
4. If 2wd, make sure the tailshaft is correct for your truck.
Changing the tailshaft is a PITA.
5. Verify which PCS your 93 tranny has.
6. You should have the updated, current, main connector, but check it.
6. The 93 TCM will control a 94-up tranny if you use the correct PCS.
 
Some info -
 
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=21&ved=2ahUKEwiFkdG8x4_lAhVGQ6wKHferAaIQFjAUegQIBRAC&url=http%3A%2F%2Fwww.atra.com%2FBulletins%2F1995%2FAllYear%2Fatb266.pdf&usg=AOvVaw1WdnHl_3bxgDpl_d-XrHO1
 
 

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Discussion Starter #3
Thanks for the information. The truck has the updated harness from the factory. Cooler lines are not a problem. It looks like the tail shaft is correct for 2WD. Can you tell me more about the up shift shaft?
 

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Discussion Starter #5
Does anybody know if a 1993 4l80e from a 2wd van will work in a 1993 2wd c3500? Is the tail shaft the same?
 

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If they are both 2wd then yes. Should swap right in.
 

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The best way to tell is if the yoke on the transmission is bolted to the tail shaft or if it is a slip fit. The bolt on (a multi-piece shaft) has the u-joint strapped on like the rear yoke.
With the slip fit the u-joint is pressed on.
A 3500 normally has the bolt on yoke.
Not sure what a van has.
There is a difference in how they seal, the slip fit has a collar and o-ring seal on the inside of the tail shaft to keep ATF from leaking from the vent hole on the slip yoke.
That means a tranny with the bolt on yoke that is swapped to slip yoke is going to leak ATF because they don't have the collar seal. Look at a slip yoke, there is a vent hole to prevent hydraulic pressure as the yoke moves in and out. That mystery ATF leak that won't go away even after new tail shaft seal.
The other way works ok because the yoke is bolted on.
Best bet is to check fit the yoke you will be using because there is an assortment of tail shafts. You never know what has been changed on a used vehicle. FSM shows the various tail shafts.
 

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Discussion Starter #8
It looks like I will be swapping an early model for a late model. I will let everybody know if i have any issues along the way. Any advice from someone who has done it before?
 

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You should get a 94-up TCM if you are going with 94-up 4L80.
GM made one, #16196390 just for 6.5 diesel with 4L80, 2wd only.
That way any 94-up 4L80 that will fit will work.
It's a plug and play upgrade for your 16147609 TCM.
 

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Discussion Starter #10
I swapped in a 94 4l80e when I got the 93 truck many years back. It worked fine until now. Do you still think my 93 need a a new tcu?
 

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Discussion Starter #12 (Edited)
I guess the question is what will happen if you don't swap the TCU? Or what happened for the last 6 years of having a mismatched trans and controller? Did that contribute to the trans failure?

Also, the part numbers listed previously, is that for a DS4 or DB2 injection pump engine? I don't need the engine/trans controller. Just a trans controller.
 

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Can't say except I have owned over a dozen trucks and burbs with 4L80's and have never had one quit, most well over 200k miles.
The 16147609 TCM is what you should have now and the 16196390 TCM is what was used in 94-up 6.5 diesels with DB2 injection.
 

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Discussion Starter #14
The part number 16196390, is the same one in my 96 3500 with a DB4 pump. That is what s confusing me. Do I need to replace the PROM as well or will the one currently in my 93 work in the 16196390?
 

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Does your 96 have a DS4 electronic IP or a mechanical IP?
DB4 is a special marine mechanical IP.
Your 96 should have a 16216588 PCM unless it has been modified.
No, you cannot swap the chips in the TCM's.
91-93 diesels with 4L80 use the 16147609 TCM.
94 and up the 16196390 TCM was used in vans, "p" trucks, military vehicles, anything with a 6.5 NA diesel mechanically injected engine with a 4L80.
That makes it a convenient solution to using a 94-up 4L80 on your 93 or any other vehicle you want to put a 94-up 4L80 in.
 

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Discussion Starter #16
My 96 is a DS4. I am having a hard time finding a replacement for the 94+ trans. I am having an even harder time trying to find out what PROM I need.



I have a spare 16147609 if anybody wants to trade for a 16196390.
 

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Discussion Starter #17

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Be careful, 16196390 was never used in trucks, suburbans, tahoes, ONLY 94-up P-chassis, vans, delivery trucks, motorhomes, ect.
That is the correct TCM in the photo, I always make the seller send me a photo of the chip inside. BCC BRBB was used in 1996 P chassis with "Y" L57 na 6.5 diesel.
You MUST get the chip with the TCM.
 

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Discussion Starter #20
So what will happen if you run a 94+ trans on a 93 TCU? What issues could the mismatched force motor cause? I had a mechanic tell me that it makes no difference which TCU I use. They will work on either one. He said the force motor kit is the same for the new vs old style. The kit includes instructions for drilling a relief hole in the 91-93 trans but the force motor is the same part for either trans. Now I don't know who to trust, just like everything else in this world.
 
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