transmission problems after gears installed

chiaronate · 09-20-2003, 02:09 AM

i have a 1994 mustang gt with automatic transmission. i've recently had 3.73's installed in place of 2.73's and am very happy with the improved acceleration. however, if i hit the gas enough (probably 1/3) the transmission slips out of gear until i let off the gas and the rpm's decrease. it then goes back into gear. i had my transmission rebuilt approximately 15,000 miles ago, and it didn't slip with the 2.73's that were in it. i read a post on here that there was an article in a hot rod magazine that said if more than 3.55's are used in a 1996-1998 mustang, the line pressure may get too high and cause it to slip. any thoughts on what could be causing this? are 3.73's too much without a computer chip?

billheis · 09-20-2003, 09:52 PM

I'm not sure on the AODE but on my AOD in 90 LX had to change the speedo gear. If you don't have the proper mph the speed sensor is going to throw off the computer. You might need to put chip to compensate. Hopefully someone with 94/95 will give correct answer.
Bill

chiaronate · 09-21-2003, 02:01 PM

a friend of mine gave me a speedometer gear from a jeep that fit, and corrected my speed reading. i think a custom chip will fix it, but it doesn't slip when i start out in first. i'll just drive that way for now.

09-20-2003, 02:09 AM	#1
chiaronate Registered Member Join Date: Jul 2002 Location: watervliet, ny Posts: 105	transmission problems after gears installed i have a 1994 mustang gt with automatic transmission. i've recently had 3.73's installed in place of 2.73's and am very happy with the improved acceleration. however, if i hit the gas enough (probably 1/3) the transmission slips out of gear until i let off the gas and the rpm's decrease. it then goes back into gear. i had my transmission rebuilt approximately 15,000 miles ago, and it didn't slip with the 2.73's that were in it. i read a post on here that there was an article in a hot rod magazine that said if more than 3.55's are used in a 1996-1998 mustang, the line pressure may get too high and cause it to slip. any thoughts on what could be causing this? are 3.73's too much without a computer chip?

09-20-2003, 09:52 PM	#2
billheis Registered Member Join Date: May 2001 Location: Fernandina Beach, FL 32034 Posts: 178	I'm not sure on the AODE but on my AOD in 90 LX had to change the speedo gear. If you don't have the proper mph the speed sensor is going to throw off the computer. You might need to put chip to compensate. Hopefully someone with 94/95 will give correct answer. Bill __________________ Bill Heiser 90 Convertable 5.0 LX, ported E7s w/ THumper valve job, TFS street, FR 65mm TB, B cam w/1.7 cobra rockers, kirban AFPR, Mac CAI, Mac Headers, off road h, 3 chamber flows, Crane ign. box, 3:73s, Art Carr AOD & 2600 converter

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09-21-2003, 02:01 PM	#3
chiaronate Registered Member Join Date: Jul 2002 Location: watervliet, ny Posts: 105	a friend of mine gave me a speedometer gear from a jeep that fit, and corrected my speed reading. i think a custom chip will fix it, but it doesn't slip when i start out in first. i'll just drive that way for now.