Car won't shift into 4th/overdrive

[smcgee]

Thanks to the many posts I have read on this forum, I just completed a DIY blown head gasket on a 1996 328i. Everything went fine and the car starts and runs fine except it will not shift into 4th gear!! On the highway rpms are 3500 at 65 mph.

Does anyone have any idea what could be the problem? The car sat in the garage for about three months while I figured out how to fix it, order parts, etc., etc. Have I disconnected something and not got it correctly connected back? I had no transmission problems prior to undergoing the head gasket repair.

I plan on servicing the transmission since it may have overheated the fluid when the car overheated due to a failed water pump. This was suggested by a local indy shop. I have checked the transmission fluid and it appears normal color but I am going to change it and the filter out anyway.

Please let me know if anyone has any ideas on what I can do.

Thanks
Scott

[downeaster1]

Do you get a transmission error light on the dash?

-Fred

[smcgee]

Do you get a transmission error light on the dash?

-Fred

No error light.

[downeaster1]

How many miles are on the car, and when was the last time you changed your transmission oil?

[qidm67]

Your automatic transmission has it's separate oil and a separate oil cooler (like a radiator, a heat exchanger). This means if your car did overheat it wouldn't have much effect on the transmission unless it was some extreme overheating.

[beskhu3epnm]

There's a relay for the gear selector position. I've heard of one going bad... It's pretty hard to get too, but it sends the signal to the TCM as to what gear is on the selector. Sounds like it thinks you are in 3. Does the RPM's rev higher through each gear when you accelerate normally (ie. sport mode)?

If you press the M button and go into D, does it then shift?

[smcgee]

Your automatic transmission has it's separate oil and a separate oil cooler (like a radiator, a heat exchanger). This means if your car did overheat it wouldn't have much effect on the transmission unless it was some extreme overheating.


I changed out the tranny fluid and filter today and it made no difference. The fluid was not burnt smelling and red. The tranny was rebuilt in april 2008 at 100,000 miles.

The battery was disconnected for about three months on this car while I learned to do the head gasket repair and get it completed. Could this have effected the electronics of the transmission?

[beskhu3epnm]

There's a relay for the gear selector position. I've heard of one going bad... It's pretty hard to get too, but it sends the signal to the TCM as to what gear is on the selector. Sounds like it thinks you are in 3. Does the RPM's rev higher through each gear when you accelerate normally (ie. sport mode)?

If you press the M button and go into D, does it then shift?

Relay might be sticking....

[smcgee]

There's a relay for the gear selector position. I've heard of one going bad... It's pretty hard to get too, but it sends the signal to the TCM as to what gear is on the selector. Sounds like it thinks you are in 3. Does the RPM's rev higher through each gear when you accelerate normally (ie. sport mode)?

If you press the M button and go into D, does it then shift?

Where is this relay located? Do you think having the battery disconnected for three months could effect the electronics of transmission?

RPMs rev higher up to 3rd speed the doesn't shift to 4th. At 65mph on highway I am turning about 3500 rpms.

Do you mean press the M button start in 1 then go to 2 then 3 then into D? If so I'll try it. I've never used the manual mode simply because I am not completely sure how it works.

Thanks for the advice guys.

[qidm67]

I changed out the tranny fluid and filter today and it made no difference. The fluid was not burnt smelling and red. The tranny was rebuilt in april 2008 at 100,000 miles.

The battery was disconnected for about three months on this car while I learned to do the head gasket repair and get it completed. Could this have effected the electronics of the transmission?

I would disconnect the battery and reconnect it. Then make sure to put the car in D and leave the A/M button alone.

[beskhu3epnm]

Where is this relay located? Do you think having the battery disconnected for three months could effect the electronics of transmission?

RPMs rev higher up to 3rd speed the doesn't shift to 4th. At 65mph on highway I am turning about 3500 rpms.

Do you mean press the M button start in 1 then go to 2 then 3 then into D? If so I'll try it. I've never used the manual mode simply because I am not completely sure how it works.

Thanks for the advice guys.

If the RPM's are on average holding on to gears longer, it sounds like your transmission believes it's still in sport mode. Sounds like a problem with the shitfter mechanism, or Automatic Transmission Range Switch:
http://img150.imageshack.us/img150/4997/89738602kj3.jpg

If the range switch has gone bad, it may detect your shifter in 3rd.
http://img149.imageshack.us/img149/5547/97828316cy0.jpg

Of course, mechanically it could be a shift solenoid in the transmission causing you grief. Selecting M and going into drive (once at the proper speed) will rule this out.

I would disconnect the battery and reconnect it. Then make sure to put the car in D and leave the A/M button alone.
Don't worry about this, I've used the A/M button every day for the last 4 years on the original transmission (to keep RPM's down first thing in the morning). It's fine to use, otherwise it wouldn't be on the car.

[Eric93se]

I know this is an old thread but I would just like to add my experience with no overdrive. Turned out to be a bad tranny computer. Car had no overdrive, and 'D' acted like 'D3' or sport mode. So it took INPA software to see that the computer saw 'D' as 'D3' and the only other gear that read wrong was '1' which read as 'D', but selecting '1' did not perform like 'D' instead it was more like D3 (because no overdrive). Changing the tranny computer fixed this.

If anyone knows (flyfish maybe) if the tranny computer needs to be coded or registered (forget what its called) to work with the rest of the electronics, it would be great to shed some light on it (and how to do it).

For anyone else that messes with the tranny computer be sure to always pull the battery negative prior to doing so.

Also there is mention of a relay in this thread, there is no relay that I am aware of concerning the 4l30E that has anything to do with the selector switch.

edit: Also just to add there were zero codes, even in INPA, which thinking back was very strange. Also manual mode was screwey, going from '1' to '2' produced an increase in RPM.

[Auto Parts Guy]

A friend of mine had an issue on his 93 (i think, either 93-95 at least) 325i auto with the 4L30E trans. He didn't have 1st gear, not sure what else. I had done the auto to manual swap on my car a while back and still had the trans computer in the computer cubby. So in the parking lot of the gym, I in the trans computer from my 93 325i and it fixed his transmission issue. No coding or anything, just direct swap. So trans could also be missing another gear and the fix may be the transmission computer.. just to add to your old thread bump.

[Eric93se]

Wow, very interesting. Reading your story I instantly said to my self that first gear clutch plates are just shot.

I was going to hold on to my other tranny computer but now I might just toss it.

[Jayprentice777]

I changed out the tranny fluid and filter today and it made no difference. The fluid was not burnt smelling and red. The tranny was rebuilt in april 2008 at 100,000 miles.

The battery was disconnected for about three months on this car while I learned to do the head gasket repair and get it completed. Could this have effected the electronics of the transmission?

I did the same thing I thought mine was low on fluid and it wasn’t. so yours was just the computer makes sense because I disconnected my battery also, trying to get my anti theft to work but I think my transponder is broke because I have no radio signal either but anyway I guess I messed up my tranny computer