Posted: Thu May 26, 2011 3:40 pm Post subject: 2003 9C1, Engine and Tranny upgrade
As the old saying goes, "just because you have it lying around, doesn't make it the best fit," may be my delima.
I have an 2003 9C1 stock. To replace the motor and tranny I have aa3.8 from a 2005 GP and a 4t65e-HD from a 1998 GP. Can this combo work? I know will have to change the drive by wire on the 3.8 and probably move my sensons over. I will also have to get the drivers side half-shaft from the 1998. Anything esle I am missing? Thanks.
The 98 4T65E-HD is weaker than your 03 4T65E in many areas... the only part that is stronger in your HD tranny is the diff...
You are far better off swapping the HD diff into the 2003 4T65E than swapping the entire tranny...
You'll have to notch the motor mount or swap the old oil pan from the l36 to get the L26 to fit. And yes, you need to swap the old throttle body and use a Gen5/Gen3 throttle body adapter (or swap the entire L36 UIM and TB)
Trans is slippin and the HD trans has 60K miles. My motor has 125k and the 2005 has 50K. My neighbor want my 3.8 to put in his blown impala.
It would be better to get the adapter IMO due to the less than stellar plastic in take of the L36. Right?
Should I look for a 2003 HD or, rebuild the 4T65E with the HD diff?
60K miles on a 4T65E doesn't mean it's not a complete piece of crap too.. they can fail far earlier than that
If it were me, I'd rebuild the 03 tranny and then if you want to, add the HD Diff, Diff Cover and Axle
There are pros and cons to both the aluminum and plastic intakes....
For the cost of a new TB adapter, you could buy the APN aftermarket plastic intake that fixes the issues w/ the plastic intake (melting around the EGR stovepipe) and still retain the cooling properties of the plastic...
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