Transmission swap

1999 GMC SIERRA
125,000 MILES • 4.3L • V6 • 2WD • AUTOMATIC
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BUOCH
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Trying to find out if a transmission is interchangeable. Have the truck listed above with 4L60E transmission. Tag on top of transmission shows 9CAD .Have trans that is sams 4L60E but tag says 8CAD .It came out of a 1998 Silverado with same motor.
Apr 19, 2020 at 5:34 PM
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KASEKENNY
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Yes. These transmissions were basically unchanged for many years. There were some differences with the early models but nothing between these vehicles. You are good to go with using a unit out of this truck.

Let me know if you have more questions. Thanks
Apr 19, 2020 at 5:48 PM
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BUOCH
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Thank you .The 8 CAD is 3/4 inch shorter but drive shaft will take that up. All plugs look the same.The 9 CAD has bolt hole on top in center but was not used.Was told 9 was year ca was for motor size and D was for location.Was checking to be sure.This site helped me before. Thank you again
Apr 19, 2020 at 8:20 PM
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KASEKENNY
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Thanks for the update. I was not aware of the 3/4 inch difference. Thanks for that information. Please come back in the future if you need assistance on other things.
Apr 20, 2020 at 8:17 AM
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BUOCH
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Transmission went in fine but converter did not line up.The 1998 model is by what GMC told me was in between year.Said flywheel from Silverado would not go on the GMC. That is what parts told me.It's a GM product hard to believe but converter nuts were half in hole.Thank you, transmission fit fine.
Apr 20, 2020 at 5:19 PM
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KASEKENNY
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I suspect the converter from the other unit or flexplate from the other unit (if you had that) would fit with no issues.

Thank you very much for this info. I have done a number of these and never had an issue. However, now that I think of it, I have not gone from Chevrolet to GMC. I never would have thought that they made these small changes between units like this.
Apr 20, 2020 at 7:23 PM
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BUOCH
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Converter was larger shaft was larger 9CAD had larger 8CAD had smaller one.Transmission same. but now l learned not to listen to people in junk yard.Thank you for your help.Back to junk yard.
Apr 20, 2020 at 7:31 PM
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KASEKENNY
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Haha. Isn't that the truth. I learned that as well with a throttle body on a Honda that "fits all model years with the same engine." It took bringing in the one off the car to show them the difference and them to search their shelf of "all the same parts" to find the one that was the same as the one I needed.

Thanks again.
Apr 21, 2020 at 9:14 AM