Shifting in "Auto" cars

[miker 5,000+ posts]

So.. I have an old BMW w/ and automatic tran.. What I want to know is, why are the RPM's it shifts at variable??? Like sometimes I will get it up to 6k rpms, then it shifts down to about 4k, then it will shift down again at about 5k... But allot of the time it usually goes up to about 3.5k-4k... then shifts out of 1st....

Why would it be doing this?

Also the car "red-lines" at 6.5k-7.5k.. It's not "bad" for the car to get up into that range for a split second is it?

Just something to note.. It's not b/c the car is cold.. I'm talking about yimes when it is fully warmed up.

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[azbass 5,000+ posts]

probably how you have your foot on the gas..

 

[PatFitz9 10+ year member]

it's either your foot, or it's just an old pos

 

[bad @SS chevy 10+ year member]

can you check the transmission fluid level?

 

[miker 5,000+ posts]

can you check the transmission fluid level?

Yes... Just did, it's perfecto.

 

[miker 5,000+ posts]

it's either your foot, or it's just an old pos

Well considering most of the "old pieces of ****" I have seen struggle to get to 80mph... I don't think thats it... lol... It is old, but it's no a POS.

 

[JLJunkieMX107 10+ year member]

On my car if you barely press the gas it will shift at low rpms, if you are WOT it will shift at redline.

 

[bball09124 10+ year member]

On my car if you barely press the gas it will shift at low rpms, if you are WOT it will shift at redline.

same with mine.

 

[IgnoreMe 5,000+ posts]

trannys work off pressure...depending on the pressure thats building up, it will either shift early, or shift late. barley on the gas, means a light early shift. WOT, means a hard later shift. and everything in between.

now im going to assume the OP already knew this, and is wondering why it shifts at 3k and then a 5k even though you keep the throttle in the same position? im pretty sure the OP is a little brighter than assuming it will shift at the same rpm regardless of throttle guys...

 

[miker 5,000+ posts]

trannys work off pressure...depending on the pressure thats building up, it will either shift early, or shift late. barley on the gas, means a light early shift. WOT, means a hard later shift. and everything in between.
now im going to assume the OP already knew this, and is wondering why it shifts at 3k and then a 5k even though you keep the throttle in the same position? im pretty sure the OP is a little brighter than assuming it will shift at the same rpm regardless of throttle guys...

Thank you

Yes. I am wondering why it shifts at different RPMs w/ the same amount of pressure (roughly)

 

[iamamp3pimp 5,000+ posts]

tranny issues...

 

[IgnoreMe 5,000+ posts]

Thank you
Yes. I am wondering why it shifts at different RPMs w/ the same amount of pressure (roughly)

how old of a car are we talking about? is it possible the tranny is electronically controlled? maybe the sensor is giving bad pressure values which is causing unstable shifting.

not to familiar with bmw's at all really though.

 

[azbass 5,000+ posts]

Thank you
Yes. I am wondering why it shifts at different RPMs w/ the same amount of pressure (roughly)

old car, auto tranny.

just maybe there could be a problem..

 

[JLJunkieMX107 10+ year member]

My old eclipse started doing this. It would shift fine one time then the next would shift to 3rd when I was at 2.5k rpms. About a month later the ***** went out.