E39touring M73tu (5hp-30 issues)

[Dark Phoenix]

Hello all I’m having a bit of an issue with my 5hp-30 I just swapped in a 2001 750il engine and trans into my 2000 E39touring and topped off the trans with new fluid and the issue I’m having is when I select reverse the trans will engage then disengage immediately and when I select drive it seems to slip a lot until I rev it up too about 3000 then it will thump kinda hard and go into failsafe 4th gear and reverse starts to work if I turn the engine off and on again same thing happens again


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[CPHES]

Cool swap - one I’ve thought about.... how was this drivetrain before? Is your battery healthy?

[Timm]

That sounds like it is low on transmission fluid - did you fill it correctly as specified here:

https://www.meeknet.co.uk/Gen_BMW/ZF...box.pdf#page=4

[purplecty]

Hello all I’m having a bit of an issue with my 5hp-30 I just swapped in a 2001 750il engine and trans into my 2000 E39touring and topped off the trans with new fluid and the issue I’m having is when I select reverse the trans will engage then disengage immediately and when I select drive it seems to slip a lot until I rev it up too about 3000 then it will thump kinda hard and go into failsafe 4th gear and reverse starts to work if I turn the engine off and on again same thing happens again


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Pics of this swap please!

Also make sure the fluid meets the LT71141 spec..

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[Dark Phoenix]

Cool swap - one I’ve thought about.... how was this drivetrain before? Is your battery healthy?

Thank you! She started life as a 10/99 528iAT and yes battery sits at 12.6v engine off 11.2v cranking and 14.1v running thanks for replying


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[Dark Phoenix]

That sounds like it is low on transmission fluid - did you fill it correctly as specified here:

https://www.meeknet.co.uk/Gen_BMW/ZF...box.pdf#page=4

Hello thanks for the url! I didn’t fill the trans quite exactly like in those instructions I believe I did fill it somewhat in that order I had it on a lift and used an electric pump to fill it with fluid while my brother shifted through the selections each time stoping for a bit and letting me fill it to the brim until it wouldn’t take anymore in any gear.


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[Dark Phoenix]

Pics of this swap please!

Also make sure the fluid meets the LT71141 spec..

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Yes of course haha I haven’t taken much but I have these

And yes! I hope I have haha I’ve been using the redline d4 atf sold on ecs tuning for this trans.


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[Aitch]

I hope you get it sorted. A V12 wagon would easily be a Jalopnik "build of the week" feature when completed.

[740il97g]

if the fluid level is correct, voltage is correct, I would make sure the correct filter is being used. If all those check out. The valve body may need to be rebuilt.

[KinkedChrome]

I have no idea about your issue, but this is an awesome build. The triple x pipe I find especially cool. Is the car loud at all or what mufflers do you have on there?

[clarkitect]

Crazy thing is if you tried to put a V12 into a 740i everyone would say it’s impossible.

Nice build. Hope topping off the fluid does the trick.

[chrisn7]

Hello thanks for the url! I didn’t fill the trans quite exactly like in those instructions I believe I did fill it somewhat in that order I had it on a lift and used an electric pump to fill it with fluid while my brother shifted through the selections each time stoping for a bit and letting me fill it to the brim until it wouldn’t take anymore in any gear.


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Its important to observe the gearbox fluid temperature as well the actions you took. Topping off is best done at 30C - beyond 50C is not recommended as it would result in too little fluid, due to contraction, on cold start

[Dark Phoenix]

I hope you get it sorted. A V12 wagon would easily be a Jalopnik "build of the week" feature when completed.

Hello Thank you very much that would awesome!!


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[Dark Phoenix]

if the fluid level is correct, voltage is correct, I would make sure the correct filter is being used. If all those check out. The valve body may need to be rebuilt.

Hello thank you for your reply I think I solved the problem I swapped transmissions with the previous obd1 M73 I had in the car and it shifts through the gears now! so I think I had a bad trans and thank god the older one was still good.

and now the only thing that seems to be left is I still have the transmission light on and I scanned it with inpa and the code that keeps appearing is (can brake signal) and internal status still says it’s in failsafe prog which I find wierd because it shifts through the gears? Haha but I will look over my wiring and see if I left something out. Maybe the E39 doesn’t have a module it needs idk haha any suggestions will be greatly appreciated thanks again


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[Dark Phoenix]

I have no idea about your issue, but this is an awesome build. The triple x pipe I find especially cool. Is the car loud at all or what mufflers do you have on there?

Haha Thank you! and I went with triple x pipe and single exit to smoothen the sound as much as possible. plus I’ve never seen it done haha and I’m glad I did it brings out the high pitch v12 sound nicely. which is hard with the m73 because it’s really raspy. but it’s not that loud haha. the x pipes and y pipes did bring down the level a bit. and with the unknown series 3 inch magnaflow at the end you can talk over it at idle.


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[Dark Phoenix]

Crazy thing is if you tried to put a V12 into a 740i everyone would say it’s impossible.

Nice build. Hope topping off the fluid does the trick.

Hello how so? I’m curious haha

Thank you!


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[Dark Phoenix]

Its important to observe the gearbox fluid temperature as well the actions you took. Topping off is best done at 30C - beyond 50C is not recommended as it would result in too little fluid, due to contraction, on cold start

Yes I agree, I also tried that but unfortunately it didn’t work. but thankfully the new trans seems to have done the trick now I just need to figure out why i get the code(can brake signal) thank you for the reply


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[Dark Phoenix]

Also just want to say the people in this forum are awesome I used to post in bimmerfest and there’s a lot les activity and help over there. It’s still a good forum but this one is much faster


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[Dark Phoenix]

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