4.6 is transmission problems
 

Long time lurker on here, but first post.
Apologies first off if this has been covered elsewhere but I couldn't find an answer.

I have a 2003 4.6 is.
My transmission totally shit itself and I've just paid an independent firm £3200 to have the transmission and torque converter reconditioned.

Prior to the problems, if I was driving in manual mode and slowed down at a junction, the gears would only shift down as far as 3rd and stay there.
This problem still exists after the overhaul.

When driving in auto (not sports mode), when I approach a junction there is a very annoying and sometimes violent jolt when the box kicks down to 2nd and 1st gears.
This was a problem before and now after the overhaul.

Anyone with similar experiences?
Any advice would be greatly appreciated.

Dont know nothing about the trans but it sounds as if the control unit is playing up. Thinking about logically the control unit should be getting alsorts of inputs from sensors around the car i.e thottle position ,speed,brakes etc,from these inputs it should determine what gear you should be in and then therefore send a signal to the correct valve in your transmission which should then select the correct gear set. ( experts correct me if I'm wrong!). Not sure where this contol box is tho. Has it thrown any codes up?

Dweeb

Also if you read further down in the e53 forum you will see people with similar issues that were resolved by replacing wiring to the gearbox.:thumbup:

In my experience with two 4.6iS'...when i replaced tranny and torque converter, there was a sensor in the tranny that i also replaced. I've heard from others about similar repairs but they do not replace the sensor and certain issues remain after repairs.

When driving in manual mode and coming to a stop, does it shift itself into 3rd or is 3rd the lowest gear it allows you to shift into? I believe it's common that it shifts itself into 3rd if you're in a higher gear unless you shift into a lower gear.

The rough downshift from 2-1 is a very common issue with the 4.6iS. In my case, a PUMA case was once opened by my dealer...but with zero resolve. They suggested "topping off tranny fluid" but that proved to be useless. The Dinan engine and tranny software helped a bit, it's less frequent but the issue still appears now and then. I've just learned to live with it and compensate accordingly. I believe the 4.8iS received a SIB to deal with it's rough downshift but nothing for the 4.6iS.

I have a 4.6is too and I've had the same problem,I got a new tranny and torque converter as well and after that it lurches forward when I come to a complete stop.
The code I got was a valve body in the transmission.

What sensor did you replace chillwilli?

Some sort of speed sensor (pulse generator/throttle position sensor?)...can't recall exactly. You can either ask one of the forum techs here or contact the dealer parts guys.

If it's in manual shift mode it is default to shift down to third on its own at a stop. You can manually shift it to first, but only at certain speed/ rpm or completely at a standstill. This is the way the tran software is designed.

When you say your trans "shit itself" what do you mean? Did it quit pulling all together or just the problems you describe?

I also have a 4.6 with the 2-1 downshift bang and it is annoying as hell. The only time I can avoid it totally is to run the A/C compressor which raises the idle a few hundred rpm, or just two foot driving when coming to a stop. I'm planning on upping the idle speed via GT1 to see if this cures the problem. I have a feeling it may just work.

-Ben

Yea I've read on this forum that upping the idle a touch can sort these things out.

Can you tell me anything else about this sensor? Lmk
Thanks

Transmission issues
 

I've had a 3.0is and a 4.6is. Each had a transmission that shit itself. On the 3.0, I damaged it by spinning in the snow at full throttle, then the transmission shifted just as I got to the pavement and blew out 2nd gear. BMW quoted me $6500CAD for a new transmission. But being the cheapo I am, I called every specialty transmission place in town to try and get a better deal. When almost everyone refused to take on the repair, that should've been my que to go back to the dealer. Instead, I made a brutal mistake, and let Dot's transmission in Edmonton Alberta, convince me that they could do the work for $1500 to $2500CAD. The work took months instead of a couple weeks as promised, and cost almost $5000CAD. The truck was half decent in forward gears, but had a terrible binding when in reverse. Bottom line: unless someone has EXTENSIVE repair experience on BMW transmissions, your better of just paying the stealer.

On the 4.6, it had the terrible "bang" when it downshifted. It started to go into a 4th gear fail safe mode off and on, until eventually it stayed in 4th. It was a US vehicle with CPO warranty, so I drove 12 hours to Spokane in 4th gear. They had ordered a sensor that the Edmonton BMW dealer had diagnosed as the problem. That wasn't the problem. BMW Spokane ordered a new transmission under CPO warranty. Bottom line: As much as we all want our transmission problems to be a $200 sensor, it seems that sometimes we just have to face the reality that the problem is in the transmission, and to get it fixed right the first time, is gonna be expensive.

Thanks for all the responses and advice guys, all taken on board :thumbup:

IIRC, the Steptronic software will not shift down below 3 until you come to a complete stop (or below a certain RPM/MPH)

Not much else i can tell you except that it should've been replaced if you had a new tranny and TC installed. You may wanna check-in with whomever did your replacement. I guess it helped that the tech that rebuilt the tranny and installed the new TC on my X was a former BMW tech.

is there any fix for this problem

I know this is a old post, I am having my 03 4.6is transmission rebuilt, so far so good, the INDY told me $4200 on the high side, spoke to him today, he told me BMW has a bulletin on the control valve body, he found that has a crack, going for new one now.
I hope this cover it, this guy has a good reputation here in NY for work on transmissions.
wow update, he just call me to tell me that DIscount Tire Direct, ship me the wrong size tires the height is wrong, and that is hurting the front and rear transmission.
And I check on the price for the tranny rebuild, torque, valve body all parts[new from BMW], check fluids on all $4200..................GOT TO LOVE THIS GUY.

It's not that you need to worry about the wrong tire size, but rather if the tires are different heights front and rear. Generally those would lead to a blown transfer case, not transmission.

fwiw, my re-manufactured trans was $4050 from BMW.

Correct epdark,I am hunting down the problem right now.I think what happen I had a auto body place replace the wheels and I had OEM on and the shop installed AFTER MARKET wheels, and I am sure there is a difference in the size of the wheels.
It's amazing that something so simple should be straight forward, but no, one dum ass comes along and tries to save his boss money and BAM, your car is f--ked.
I have to check these guys all the time, and they say ,what You want it perfect, YES I WANT IT PERFECT, I PAY MY BILLS ,SO DO IT RIGHT.

What's the name of my tranny builder shop.

Wrong tire ratios, etc will do WONKY things on the 4x4. Just because a tire fits, doesn't mean it's right. So did Discount Tire ship you the wrong tires or the shop ordered the wrong aspect ratio. Whomever installed the tires would have known it was the wrong size IF the wrong tires were shipped..

I've had plenty of different sized wheels ....on the X. It all boils down to keeping the correct tire ratio. I HAD a HARD ON for some Michelin Super Sports. Played around with different sizes they had in their lineup, but nixed the idea as I did not find a correct working ratio.

hi Jsoto,I think it was the body shop that gave me the after market wheel, they are all Michelins Latitune HP [9.5"front,10.5"back,radius20"],I am waiting for the X5 to come out of the tranny shop.
The shop is A&A transmission in Thornwood NY[Westchester].he is spot on so far and replacing all the big stuff with OEM.There was a crack in the valve body,that is a big dollar item [$1524.85] Alpina for V8.

Thx for the info.

There are 2 tranny shops I have on my list of ref. One in CT who is the ZF rebuilder of all rebuilders. So faster turnaround, but you get their reman. units - core swap I presume.

Then there is a joint in NJ. I can't recall their name. They do High End Modified Valve Bodys, etc.....I would seek them if I went for a rebuild.

Who is your guy in CT? I have no issues with my tranny so far ('03 4.6is with 121k miles), but I'd like to have this ready for when the inevitable happens.

By the way, my 4.6 has had the stock wheel and tire set up since day 1. Nothing but Michelin Diamaris all around and all 4 tires changed together, never just fronts or rears.

Who knows...