E34 Auto Trans & Engine Braking Is This A Quirk ? Or A Problem ?

[spinnakr]

92 E34, 525i auotmatic 195k....runs fine after some major vandalism repair,(DME wires cut and relays tossed.Only remaing issues are: SRS and ABS lights remain on ,which probably need a dealer reset)

My question is, in either mode, M or E ,when I downshift,for braking (ie.) decending a moutain road there is no braking from the engine as is typical with most auto trans I have driven. The engine RPM's don't change (increase) nor is there any decrease in the vehicle speed ?
Searching the archived posts, I have not seen this issue posed, quite frankly i am puzzled.

If I fiddle with it, and,downshift, or change modes a few times, I ultametly will get a "trans fault",which is cleared by stoping and restaring the engine. GO FIGURE..any help is appreciated.

[genphreak]

In mine, downshifting will do what one expects, ie it will engage the lower gear and engine brake. This goes for S/E and M modes. Not sure what your problem might be though- first thing to check is the contacts on the selector though These do not last forever... and are a common problem for us.

I expect it could confuse the tranny computer if a contact in the switch wasn't engaging properly.

[AllGo'n'Show]

Mine only engine braked when it was in S, no Button in E then downshift.

I can let you know if it acts different once rebuild is complete

[neil_004]

Mine works as expected in all trans modes (depending on lever position). I think our cars share a trans (a GM 4L30E). It has a manual valve body but the trans position switch always seems to win.

[winfred]

if you down shift it should slow the car if everything is working properly

[RobE34]

Occasionaly-not every time- when I am cruising at speeds above 80k/m and back off, the engine revs will remain constant for a varying period of time. This is only on flat or near flat road. I have never had occasion to downshift but I'll try it and see what happens. Not a big issue but two reputable mechanics can't find any reason why she does it. Nothing mechanical or electrical appears to be sticking or jamming.

[spinnakr]

RobE34...I'd like to know what you find.....

[spinnakr]

Ok,,,now that i know it is not normal based on your respones; any thoughts on what the problem may be? (1.) electrical
(2) trans computer
(3) mechanical within the trans?

[danzee]

The trans will not downshift if it decides you are going too fast for the gear you selected. Once it does downshift though, you should get substantial engine braking. At least that's how my A4S 310R works.

[Airborne001]

Not to highjack this thread, but do you guys have any opinions for/against shifting into S3 when coming down from higher speed? I usually do it at about 60mph when going up a ramp off the freeway. I am pretty sure I am within the sugestions my OM makes, but wanted to see what you guys think.