HT4100 4.1, 4.5, 4.9 Discussion, Need transmission advice, please! in Cadillac Engine Technical Discussion; Folks,
This is a followup to an earlier thread I started http://www.cadillacforums.com/forums...rcarriage.html .
The buzzing noise has become more frequent ...
The buzzing noise has become more frequent and I now strongly suspect it is transmission-related. I say that because I slipped the trans into neutral once this week when I heard the buzz and it stopped immediately! Also there's a bit of uncertainly when it shifts from first into second. So NOW I'm thinking this just MIGHT be the sound of gears not meshing properly? The fluid is full and in fact has been recently changed. BUT...I am pretty ignorant about what's going on here. I guess I have always thought of transmissions as being sort of sealed units that are commonly just replaced (ouch!). I'm hesitant to take it to my semi-incompetent dealer because they have already failed to diagnose the problem plus the cost. And I'm leery of going to some franchise shop like Aamco. Does this sound like a familiar problem to anyone? Is is something that could possibly be fixed without replacing the transmission?
I'm not convinced it's the transmission...my guess would be a rattling catalytic converter. Just because it stops when you put it in neutral doesn't mean it's the trans. The engine sends more vibrations through the chassis in "Drive" than "Neutral," so I wouldn't worry yet. That being said, you should probably get it checked out.
Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
Re: Need transmission advice, please!
Buzzing within the trans is usually a weak front pump or the pump sucking air. It quits in neutral because the pump only works in gear to pump fluid thru the trans. You might get lucky changing the trans filter and filter o ring, sometimes the o ring is omitted or is cut, both would cause the trans to suck air to a degree. Most times though, its an early warning of pump failure.
Carnut may be on the right track; the other more recent symptoms are a hestitation in upshfting into 2nd, and I also sometimes notice a truck-like "rrrr-RRRR-rr in first gear when driving slowly in my parking garage.
My mechanic who hasn't seen it yet mentioned a solinoid?
I'm going to take it to his tranny specialist on Monday and will report back..
OK folks, here's the answer: all of the described symptoms were caused by low fluid! Well of course, you say, but I thought you said you'd checked the fluid! RIGHT? Here's the tip from the repair shop (in Vienna, VA -- which is just excellent, by the way, if anybody wants info, contact me): check both sides of the dipstick. My system was four quarts low, but the dipstick (at least on the side I checked), said FULL. Turns out some bolts were loose -- they're now torqued and I'm back "drivin' down the street."