need help with strange noise when cold starting!!!

ok so here is the issue.

i have the ls v6 model

when i turn the car on for the first time in the morning i hear a loudish noise from the engine bay, only in gear, does not make noise in park or nuetral, and stops after only 3 or 4 minutes.

here is some info, i have had this car for about a month... it did not have this issue when i got it. i replaced the distributor cap and rotor the day before i had the timing belt replaced, and i had to remove the battery and battery stand/holder to do the replacement... when i got the car back from the shop from doing the timing belt and water pump is when this started happening.

i just brought it home today after the shop looked at it due to the sound, and they say the noise is coming from the transmission side of the engine and cannot completely locate the problem, but they said i shouldnt worry about it too much and i should be ok for a good while... they are saying its most likely a noisy pump in the trans???

i am looking for a few opinions on this, and if it could be something else entirely that may be easy to fix...

any help would be great!!!

bump:

nobody has any idea's????

Mitsu timing belts are fickle things where did you take it. When I get mine down I either take it to dealership or a place I know that has an old mitsubishi tech do it. And no one will ever do it other than that guy. I have even called Chrysler dealers and asked the etch if they felt comfortable doing it since engines are same in sebring he said no he would not think they are qualified to do it. I have attempted to do it myself but I was off by 1 tooth and just said f it. Anyway good luck

Also try to describe noise, is it squeel, is it ping, is it bang, does it increase with revs, does it only increase in drive with revs, have you had someone other then shop turn car on while u listen in egine bay to locate sound etc. Maybe that info can help someone narrow it down.

I'm curious. Why were the battery and battery tray removed to change the timing belt and water pump?

Nevermind my above post. I overlooked the part where you said you changed the cap and rotor my bad.

bgood: its hard to describe the noise it is a constant noise "speed wise" that does not accelerate with rev or speed actually goes away when i hit the gas even lightly, doesnt sound like bad bearings, if i had to put something to it, the first thing i thought of was MAYBE sounding like a loose wobbely belt tensioner but still thats a little off what it sounds like it goes away after on 3-4 minutes which made it hard for the mechanic to attempt to locate, also inside the car it def. sounds on the t.b. side but the mechanic says its 100% transmission side he said he used a stethascope and all.

i would have taken it to the dealer but the closest dealer is 40+ miles away and was off a tooth when i got it done. i may still bring it to the dealer now that its running better "not missing" i am still getting the p0431 "catylist bank 2" cel but there is no indication that the cat is bad performance wise.

if i can get a friend to hit the brakes for me ill record the sound the next time i can...

You should check your motor mounts,had a similar problem turned out that's what it was.

My Galant used to do the same thing when it was 3.0L A/T, but after the manual swap, it went away, though my mounts were shot.

My Eclipse currently does the same thing. 3.0L A/T, and I suspect the motor mounts.

I used to think it was the transmission in the Galant, but knowing what I know now (3 years later) I would definitely start with the motor mounts. Which I plan to replace in the Eclipse eventually to test my theory. Both cars began this around 100k miles and it seems about right with the abuse most of them take.

im having the mounts checked on monday anything that should stand out if there bad that they could miss???

Front and rear should be easy you can almost just tell by looking. When rev engine it will rockk forward or backward then rock to original position when u lett off severity of rock will depend on how bad monuts are. As for side and trans mount you can't tell until u pull them cause the side mount has rubber pieces blocking the view. Let me know I have prothane mounts but I did windo weld method for my rear prothane for front and new stock for sides

well if the timing side was reinstalled incorrectly after doing the belt could it make it sound like its on the trans side??? cause i had no issues prior to getting the timing belt done...

UPDATE:

so the sound is not going away now its muffled a bit after a few minutes but its not going away now, i can here it after its warmed up when i go from a stop and lightly hit the gas then goes away after only a second or 2, "like driving away from a redlight...

update bump...

so i am def. getting the mounts checked tomorrow morning and i will post the outcome of the diagnosis when i get back...

on another note, my car doesnt seem to like the rain but what i believe it is when i installed the cap and rotor, the cap came with cheap screws and the one on the bottom of the cap closest to the firewall snapped when i tightened it i didnt even get it real tight before it snapped...

im also going to see if they can get the broken screw out so i can fix that...