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Old 05-26-2012, 05:39 PM
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TJ Motor and Transmission changes.. HELP

Between my son and I we have three and a half Jeeps all Wrangers. A 1995, a 1999 4.0 5 speed, a 2005 4.0 6 speed Rubicon, and a wrecked 2004 4.0 Auto with overdrive. I just bought the 2004 for the motor. The 1999 motor had 165,000 miles on it and burnt up, overheated and now no compresson. I would like to put the 2004 motor into the 1999. What changes will I have to make? Also I would like to put the Auto from the 2004 into the 2005, Is that possible? The 1995 will be for sale after I get the other two running. Thanks in advance for the help. I hope for follow up questions about details that I will be glad to answer
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Old 05-26-2012, 06:42 PM   #2
Knows a couple things...

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The 2004 42RLE automatic transmission is the same as the 2005 42RLE, they are interchangeable. However, you won't be able to easily get the 42RLE automatic transmission to work since the engine computer in the '99 is not even close to being able to talk to the 42RLE's transmission computer. It's like 2004 speaking advanced calculus between the engine computer and transmission computer and the '99 not having any ability to speak with that transmission's computer at all. A 32RH 3-speed automatic would bolt right up to the '04 block and present few problems getting it working. Or use the existing 5-speed without problem with the '04 block.

Installing the '04 block into the '99 shouldn't present any issues but you'll need to swap the ignition, distributor, exhaust header and upstream 02 sensor from the '99 into the '04 block. Using the intake manifold and throttle body and all its sensors from the '99 on the '04 block would probably be required too. There are just too many ignition and changes between the two model year engines to make the '99 computer's happy otherwise.

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Old 05-27-2012, 10:00 AM
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A 2003 not a 2004 engine

Thanks for the reply but I got a few things wrong. The junk yard delivered the wrecked jeep today and it is a 2003 4.0L with an Automatic with overdrive. I would like to install the 2003 4.0L into the 1999 4.0L with a standard Trans. I would be keeping the standard in the 1999.
I would then like to take the 2003 Auto and put it in my 2005 Standard Shift. My 2005 is a wrangler Unlimited ( longer wheelbase ). 4.0L Six speed Standard. Are the Rear axle ratio the same between the 2003 Auto and the 2005 Standard or how can I tell the difference. Would I need to use the transfer case from the auto or are they the same.
Maybe I am trying to use too many parts from the wrecked jeep. thanks again
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