96 540i e39 can bus problem an more fun

[Jharbertbmw]

Ok the PRESENT PROBLEM : the shop can not read the codes from can bus cause of not enough power or some problem down the line
THE ACTUAL PROBLEM : driving down the road after work something just stop all my acceleration with a thump around 60 an 2g rpm ,like the shudder problem but lots rougher.
I pull over look it over try an get the codes but my foxwell scanner won't read this car so, I drove at low rpms the rest of the way home an , playing with I I could tell it was happening I acceleration not when at low rpms ...its beyond me
AFTER: occasionally driving it to store an back over about a week an it has stopped completely

Next: I get my 2nd diagnosis to approve to resolve the can bus issue they say they unplugged the alternator an it worked by some magic

So there magic ball says alternator needs replaced

QUESTION: Yall are tried an true does this check out, or should I ask them to do a few other things to rule that out like the multimeter test or just replacing the battery first ???

[Jharbertbmw]

Update : conclusion to the problem according to shop is the alternator was spiking,

after asking them a few questions I hit something they had not found since it's been there
Problem: i let it warm up every morning all i do is start it i usually hear a slight tap once it's at running temp , i told them to start it let it sit for 15 20 mins to running temp an go an listen

Conclusion : no tap or anything of the sort found but found the alternator they put on was also bad so *criiiiinge*

[Jharbertbmw]

Help : above mentioned is @ bimmeronly plano original problem being a common torque convertor shudder real noticable dipping in my rpm when holding it @2g 75 80mph doesnt happen in manual.mode at all

*Initially can't get any codes cause of can bus *replaced alternator
*Afterward no codes (obviously cause they reset everything )
* only notable problem is major leak around the ac compressor
*going over focus problems I have found to confirm that shudder still a present problem
* they answer Im getting is check an fill transmission fluid
* if that doesnt fix put in a estimate for new trans

[Jharbertbmw]

Update
* according to the shop cant be the same problem because it's different transmission
* went over same symptoms an same way to keep the problem from happening
* they going to top of trans fluid, an test drive to compare (no notification whether its low or not )
* if that has no effect move onto transmission temp an a bill for new trans *CRIIIINGE*
HELP

[MarcoZandrini]

Find another shop. Try www.bimrs.org to find a reputable indie shop that specializes in bimmers.

[Jharbertbmw]

Yeah I figured that's what I was gonna get bimmersonly is another bmw certified shop they made sure to point that out

Ive made another post on e39 forums haven't gotten round to updating this one completely

No longer at the shop

Upon arrival I was finally told the car will no longer shift from 3rd by itself

(I've had similar issue where it won't shift from 4th but dropping rpms always fixed it, an it was never a common problem )

Pulls lots harder than before

Checked an filled trans fluid less than a quart low

Side note: person at the desk leaning towards it being something to do with a temp sensor or vavle body