e34 Transmission Issues

[Incantation]

Hey guys,

Ok, here's my problem. I have an AUTOMATIC 1990 e34 535i with about 120,000 miles, up until recently it ran perfectly smooth with no problems. Then, all of a sudden the automatic shift points started going up (meaning the car would shift at higher rpm.. even on minimal throttle).

Any ideas? I had the transmission serviced recently; they changed the tranny filter as well (something i'm not sure had ever even been done). The tranny fluid colour was also darker than it was a few months ago; a few months ago it was pink.. not it was dark-ish in colour, but did not smell burnt.

So the service went fine; they added some additive that increases friction so that the shifting would return to normal.. not sure how that worked. Anyway, there has been no change. So, basically what happens is that on light throttle off the line the car will shift into second only after 3,000 rpm where before it would shift very smoothly at maybe 1,500. It doesn't get much better when the car is warm, either. So, I have started driving in "M" so that the car shifts at its normal spots. It is very hard for me to do otherwise because if I am driving slowly in the city in 2nd gear, then give it some gas the tranny will drop down to 1st and give a kick.. that can't possibly be good for the car.

So generally I will keep it in M2 and drive in the city like that for the most part.. sometimes in 3 and only shifting to 1 when going up an incline.

Any suggestions?

[tim]

Not knowing the exact tranny in your car, from your description it sounds like you are low on fluid. Also, i'm not about any additives "that increase friction", so I'm a little suspicious about your recent service. If it were me, I'd drain and refill according to spec, and see what happens. From there, I would investigate a valve body rebuild-could be one of the solenoids is going bad.

[Elekta]

My wife's 535iA had the similar issue, and it was fluid level. Take it back and have them recheck the fluid, or even replace it again.

Then I would disco the battery, touch the leads together and reset the tranny computer. There is a shift memory procedure, but I don't have a link to it. It may be just going up to 50mph, and then coasting for a mile....something like that.

It was not the valve body on my wife's car, as it shifts like new...(1992 with 107k)

[pmlmotorsports]

I believe it's the electronic solenoids that control the shift points. Have them checked,

[tim]

The shift points are set by a combination of line pressure, speed sensors, and throttle position through the tranny control module. Late shifting is usually due to either: insufficient line pressure (low fluid level, valve body blockage), slow or stuck solenoid (usually causes "trans prog" with either a solenoid or temp code thrown), or failing speed sensor(s).

Now since you recently had it serviced, low fluid is by far the odds on bet, with valve body coming in at about 7-1, and failing solenoid way down at 20-1, since you haven't thrown trans prog yet.

[Elekta]

^^^^What he said.^^^

[marven]

Not knowing the exact tranny in your car, from your description it sounds like you are low on fluid. Also, i'm not about any additives "that increase friction", so I'm a little suspicious about your recent service. If it were me, I'd drain and refill according to spec, and see what happens. From there, I would investigate a valve body rebuild-could be one of the solenoids is going bad.

Speaking of Tranny - does anyone know how long a tranny typically lasts on the E34? Mine is a 1990 with 270000 km....

Thx
Marven

[tim]

It depends on the tranny. For automatics, problems are inversely correlated to the amount of periodic maintenance. For a well cared for GM or ZF tranny, lifetime could go 250k(400k km), I would think subjectively. Eventually the clutches and torque converters wear out, but properly rebuilt could go another 250k. Marvels of engineering, really...

[Incantation]

wow guys thanks for all the suggestions.

since the problem began before the tranny service.. i am thinking that the low level possibly is not likely.. but i will have that looked at.

tomorrow I will try and disconnect/reconnect the battery.. hopefully that will be the solution.

anyone have any idea how much it will cost to have the solenoid(s) fixed if that in fact is the problem?

[Randell]

Speaking of Tranny - does anyone know how long a tranny typically lasts on the E34? Mine is a 1990 with 270000 km....

Thx
Marven

my ZF just died at 266000km, so unless yours has already been rebuilt at some point in the car's life, I wouldn't be expecting too much more out of it...