[SlowE92]

Transmission will not go into D, it goes into m2 for some reason. When i pull it over to sport mode it wont upshift. Noticed this today could this be a contributing factor?

[konstat]

I’d think lack of fluid flow to the valve body could possibly do that. Could you also check trans fluid level?

Can you link any event to when it started happening? Were you doing work in the area of that line before it started happening? Any codes?

[SlowE92]

All i did was change the fluid i havent checked the trans fluid level, tbh i didnt know we could do that. I had a old transmission that would not engage reverse and it did the same thing when put into drive. I swapped it out for a new one and now the reverse works but the drive issue still persists. I straightened out that shifter rod and it didnt do anything so im thinking i might just need a new shifter. But im not sure

[konstat]

Originally Posted by SlowE92

All i did was change the fluid i havent checked the trans fluid level, tbh i didnt know we could do that. I had a old transmission that would not engage reverse and it did the same thing when put into drive. I swapped it out for a new one and now the reverse works but the drive issue still persists. I straightened out that shifter rod and it didnt do anything so im thinking i might just need a new shifter. But im not sure

To check fluid level you need to start car, pull fill plug, and then warm up the trans fluid to 40 deg C. Inspect fill hole for a small stream of fluid coming out. If it doesn’t then your fluid level is too low.

Put fill plug back in then turn off car and wait for car to cool down. Start car again remove fill plug and fill with about half a liter. Let fluid drain out until fluid temp is 40C and put fill plug back in. You’ll notice a small stream which is exactly what you want.

I thought you mentioned in the other thread that you replaced the shifter with a new one?

Since you said you coded the TCM with the swap I’m assuming you’re using the TCM that came with the new transmission and not the old one?

[SlowE92]

Originally Posted by konstat

To check fluid level you need to start car, pull fill plug, and then warm up the trans fluid to 40 deg C. Inspect fill hole for a small stream of fluid coming out. If it doesn’t then your fluid level is too low.

Put fill plug back in then turn off car and wait for car to cool down. Start car again remove fill plug and fill with about half a liter. Let fluid drain out until fluid temp is 40C and put fill plug back in. You’ll notice a small stream which is exactly what you want.

I thought you mentioned in the other thread that you replaced the shifter with a new one?

Since you said you coded the TCM with the swap I’m assuming you’re using the TCM that came with the new transmission and not the old one?

Yeah unfortunately this is the shifter that i had, i bought a different one off facebook market place but to no avail. And yes im using the new TCM that came with the new transmission. But the same issue still persists with changing it out.

[konstat]

That’s pretty wild it sounds like you have all new hardware. I’m wondering if there’s an electrical issue with your car somewhere. The only thing I can think of at this point is the TCM wire harness.

[SlowE92]

Originally Posted by konstat

That’s pretty wild it sounds like you have all new hardware. I’m wondering if there’s an electrical issue with your car somewhere. The only thing I can think of at this point is the TCM wire harness.

Yeah im going to change out the wire harness and see if that does anything, its pretty cheap so im not too worried about it. Ive removed the jb4, xhp flash, took off the bef and flashed the stock map through mhd and this issue still persists unfortunately. Something else i noticed is my battery is low voltage, it does not reach above 13.2v when the car is running and it dips below 12 when the car is off. Im going to sht a chicken if this whole time its been a bad battery so im going to order a new one. I just never took it into account bevause the car starts up just fine no long cranks or anything.

[SlowE92]

Originally Posted by SlowE92

Yeah im going to change out the wire harness and see if that does anything, its pretty cheap so im not too worried about it. Ive removed the jb4, xhp flash, took off the bef and flashed the stock map through mhd and this issue still persists unfortunately. Something else i noticed is my battery is low voltage, it does not reach above 13.2v when the car is running and it dips below 12 when the car is off. Im going to sht a chicken if this whole time its been a bad battery so im going to order a new one. I just never took it into account bevause the car starts up just fine no long cranks or anything.

Originally Posted by konstat

That’s pretty wild it sounds like you have all new hardware. I’m wondering if there’s an electrical issue with your car somewhere. The only thing I can think of at this point is the TCM wire harness.

I also need to order that diagnostic tool you mentioned before. Im somewhat new to these bmw’s still, i had an r35 previously, so tackling all of these repairs have been a sht show for me.

[konstat]

Originally Posted by SlowE92

Yeah im going to change out the wire harness and see if that does anything, its pretty cheap so im not too worried about it. Ive removed the jb4, xhp flash, took off the bef and flashed the stock map through mhd and this issue still persists unfortunately. Something else i noticed is my battery is low voltage, it does not reach above 13.2v when the car is running and it dips below 12 when the car is off. Im going to sht a chicken if this whole time its been a bad battery so im going to order a new one. I just never took it into account bevause the car starts up just fine no long cranks or anything.

Originally Posted by SlowE92

I also need to order that diagnostic tool you mentioned before. Im somewhat new to these bmw’s still, i had an r35 previously, so tackling all of these repairs have been a sht show for me.

Once you get through all this you’ll come out on the other side a much stronger person lol. The lows can be pretty low with these cars but the rewarding feeling of fixing the issues and the joy of driving it keep us coming back.

BMWs and probably German cars in general are notorious for electrical issues due to fluctuating voltage/current. For example, a bad voltage regulator on the alternator can cause all sorts of unrelated electrical issues to crop up.

There’s a charging algorithm that BMW uses as the battery ages to ensure it’s providing optimal voltage/current. So because of that you’ll also need to program the battery to the car, which can be done with the diagnostics package via protool. Basically need to tell the car how big the battery is so that it doesn’t overcharge it.

Curious, why’d you end up parting ways with the R35?

[BRG_N54]

Originally Posted by konstat

To check fluid level you need to start car, pull fill plug, and then warm up the trans fluid to 40 deg C. Inspect fill hole for a small stream of fluid coming out. If it doesn’t then your fluid level is too low.

Until you perform the correct fill procedure, we won't be able to diagnose much. As outlined here by konstat, it is a very specific process and you must monitor the fluid temp as prescribed. If the fluid is allowed to exceed 40C it expands and you will underfill. The vehicle must be level when this is performed also. Correct fluid level is critical to proper transmission operation and longevity.

[SlowE92]

Originally Posted by konstat

Once you get through all this you’ll come out on the other side a much stronger person lol. The lows can be pretty low with these cars but the rewarding feeling of fixing the issues and the joy of driving it keep us coming back.

BMWs and probably German cars in general are notorious for electrical issues due to fluctuating voltage/current. For example, a bad voltage regulator on the alternator can cause all sorts of unrelated electrical issues to crop up.

There’s a charging algorithm that BMW uses as the battery ages to ensure it’s providing optimal voltage/current. So because of that you’ll also need to program the battery to the car, which can be done with the diagnostics package via protool. Basically need to tell the car how big the battery is so that it doesn’t overcharge it.

Curious, why’d you end up parting ways with the R35?

Yeah ive noticed this car is really finnicky when it comes to electrical issues. I have a couple lights on the dash in regards to the sunroof and the sos. It sucks that im having these transmission issues at the moment. I sold my r35 just due to cost. Went through 2 transmissions. Shep trans was 18k and let go. Spent around 50k just in parts. Ive spent maybe 1500 in parts so far on this car lol.

[konstat]

Originally Posted by SlowE92

Yeah ive noticed this car is really finnicky when it comes to electrical issues. I have a couple lights on the dash in regards to the sunroof and the sos. It sucks that im having these transmission issues at the moment. I sold my r35 just due to cost. Went through 2 transmissions. Shep trans was 18k and let go. Spent around 50k just in parts. Ive spent maybe 1500 in parts so far on this car lol.

Wow alright so you’ve been through the ringer already, this is just another rodeo for you. Glad this car has been more cost friendly for you (which I can’t believe I’m saying about an N54).

The Protool software I mentioned to you will help you get some specific codes for the other modules that are giving dash lights. I’d also recommend getting the coding software as well since you’ll be able to program out the features in a module that are giving you the code.

For example, I had a rear turn signal light malfunction dash light. The turn signal light worked completely fine and instead of changing wire harnesses to try to solve the issue I disabled the rear turn signal checking function and dash light is gone.

[SlowE92]

Update to this thread. Replaced the battery, shifter cable, and the wiring harness to no avail. Officially stumped.