trannyproblems 96 to 98 swap ? - Bimmerfest - BMW Forums

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7 Series - E38 (1995 - 2001)

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Old 09-24-2012, 04:59 PM
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Location: SAN DIEGO
Join Date: Sep 2012
Posts: 4
Mein Auto: 96 740il&98 740i
trannyproblems 96 to 98 swap ?

new to the bmw world bought a 96 740il for $450 bucks that had been sitting for two years got it home started wrenching on it had to change osv on back of intake did not reuse the tork screws had to make tools to get them out "stupid" replaced water pump .belt.plastic fan blade and a side marker light loved that car, lady i got it from never had any body in the back seat super clean ,, nicest car ive ever had abs light and check engine would come and go and then a 16 year old girl pulled out in front of me and i stacked it at about 50 mph wasted!!!! so now yesterday i bought a 98 740i with a bad tranny for 800bucks thinking i could pull tranny out of 96 drop it in 98 after reading bunch of posts tryed to trouble shoot the 98 by checking codes with obd2 got po600 and cant remember the other one it was something with engine temp sensor temp gauge pegs to red at start up the shifter will not click into 2nd and the inst cluster gear selctor, lights up for about 2 seconds goes out and nothing no light comes on for gear selection no manuael and sport light nothing trans failsafe program in cluster so i checked all fuses replacing battery with a new one.swapping the tcm along with the modgle that was next to it white plastic one both behind glove box, changed trans filter and fluid and the computer under hood only one computer under hood would fit the 98 from the 96 diffrent plugs dissasembled the switch on side of tranny cleaned all contacts had to drill out factor rivets ond screw back together then tryed it again got abs light on from the 96 now, still got trans failsafe mode now not program got car on lift can get tires spinning around 2000rpm couldnt do that before ....just frustrated what now the two cars have diffrent trannys will the enter change what about that diffrent harrness plug under hood on 96 is the tranny bad or did the cigeriett lighter set some thing off actually read fourm about liter screwing up the tranny i think bmw should fire all the electrical eng. over there cause it seems like there alot of electrical issues ...please help thank you
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Old 09-24-2012, 05:34 PM
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AndrewZ AndrewZ is offline
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Location: Burbank, CA.
Join Date: Feb 2006
Posts: 11,068
Mein Auto: 91 E30
Welcome, moved your thread to the E38 forum. Maybe someone could shed some light on this.
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Old 11-03-2012, 04:53 PM
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Location: SAN DIEGO
Join Date: Sep 2012
Posts: 4
Mein Auto: 96 740il&98 740i
Failsafe program

So i swapped trannys took the hp 24 and put in the hp 30 that i know was good still have failsafe program tried to reset everything will no luck was wondering if the hp 30 tcm wont talk to the cars ecm because the programed vin numbers are diffrent on the two modules and i nedd a gt1 scanner to rewrite the vin on the hp30 tcm so they can talk ... Does that make any sence at all cause im a wrencher not a computer geek or is my mind just messing with me cause it aint use to all this bmw b.s cause it has chevy software installed please help thank you
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Old 11-05-2012, 03:54 AM
mgoods50 mgoods50 is offline
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Location: Nashvegas
Join Date: Nov 2012
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Mein Auto: E36 M3
I am not sure this is possible, but you're barking up the right tree. You've gone backwards in terms of transmissions if I'm understanding properly. It's more than the VIN. This is a bit outside my comfort zone, but I would first try for the heck of it swapping the transmission computers-- the hp30 and hp30 tcm should be together, and the hp24 / hp24 tcm should be together. Am I following you-- you've got a 24 tcm and a 30 transmission installed now?

BTW- don't wipe your hard drive just yet- while the GM software will hurt you sometimes-- it can also help.

And for heavens sake- stay away from eBay GARBAGE Gt1!!! IF this is an avenue you want to pursue for coding / reading / diagnostics- PM me (if we can even do that as new members) and I'll point you in the right direction. I don't know if TOS allows for openly discussing that stuff.
It's not what you buy, it's what you build- Unknown
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Old 03-25-2013, 06:44 PM
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Location: salt lake city
Join Date: Mar 2013
Posts: 1
Mein Auto: 97 bmw 740il
Did u find the way to fix the issue?

Hello, I just wanna know if u where able to complete the swap on ur bimmer, I do have a 5hp30 and I would like to install it in my car that used to have a 5hp24, what do I need to do to make it work on my car? swapping the transmission computer was enough? please let me know
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Old 03-25-2013, 07:35 PM
speedkingrc speedkingrc is offline
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Location: suffolk Virginia( 7 cities)
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Mein Auto: 88 BMW 735i
me too
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Old 04-22-2013, 09:39 AM
krzekool krzekool is offline
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Location: NYC
Join Date: Aug 2011
Posts: 16
Mein Auto: '98 740 94'540 and a M6
5HP24 to 5HP30


It is to mu understanding that this cannot be done....I was also thinking of doing it because the 5HP30 is a stronger tranny as opposed to the 5HP24.

the 24 is electronically controlled with respect to the engine output and the tranny is tuned to 80 -90% of it's power so as far I know no one has done it. But with discussions like this we might figure it out.

I would be willing to ask my contacts at BMW Engineering group.....but I assure you they might not want me to know that info, but I'll ask.

Good Luck....
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