RPM drop climbing a small grade

[jayo73]

I'm new to the Bmw. I just purchased a '95 525i auto with 193,000 on the clock. I noticed rpms drop about 200 or 300 rpm when climbing a small grade then when it levels back out the rpm raise. Also noticed at about 55 mph i see the rpm drop for a split second along with a chatter then the rpm raise again only a couple hundred rpm. Is this the lock-up converter having issues or is this electrical? I had a mechanic friend tell me to adjust my detent cable. oh forgot to mention this is happening with the cruise on if that makes any difference never drive with my foot if I don't have to. I speed to much!

[genphreak]

Welcome to bimmernut, jayo.

Yours is a bulletproof choice and probably the most practical larger BMW, well done. I like my M50 ones a lot.

I think slack in the accelerator cable to the CC unit causes a drop in speed after setting the cruise speed. In the pedal cable, a little slack should be just (but just barely) noticeable. Simply adjust by hand.

Going up hills in any auto will cause a rise in rpm (slip in the fluid going through the torque converter) but if you get chatter you have a problem with the trans- probably just needs new fluid or the level corrected. Suggest changing existing fluid several times in the next 10,000 miles as you only get 1/3 of it swapped in each change as not doing this if it hasn't been swapped frequently enough in the past will promote tiny plaque build ups in the valve body. Swap the filter and pan gasket in the first and last change and make sure you use the correct fluid. (Here in Aus they call the synthetic stuff I use in all my autos Castrol Transmax Z).

The most important thing is the fluid level- you must check and top it off twice once the trans fluid reaches different temperatures following each change. If the trans runs above or below the specified level, strange outcomes are assured... so u best check pronto.

[jayo73]

Ok Thanks genphreak