I got a stock 91 firebird with a automatic trans. So im sure it has a 700r4 in it. when i accelerate i hear a rattleing noise coming from underneath the car. It dont sound like grinding just rattleing. And when i press on the gass peddel my RPM's stay low; low as in when i iv never seen it get over 4000RPM. when im just cruising at 40mph it stays at 1100rpm. Is it that my trans is going out?

 

I've never heard of a tranny making a rattling noise - lots of other noises, but never a rattling.

I'd check other sources - like loose exhaust first.

And I'd readjust the TV cable might solve the low rpm issue.

 

Its probably your transmission mount broken.

 

Pumps will rattle when they go out. The trans would be acting all sorts of screwy in that case

More often, the converter bolts get loose and allow the TC to rattle against the flexplate. Drop the dust cover and see if all 3 are tight. Use a bit of locktite on them for future peace of mind

A bad trans mount will allow the tailhousing to bang into the floorpan under accelleration. His rattle is at low speed cruise, so thats out. If its more than a few years old it wouldnt hurt to replace it though. +/- $5 They do wear out quickly

Cats rattle when they clog up and pieces break free. When you're under inspecting the converter bolts bang on the cat with your fist or a rubber mallet

Another common rattle is the cat heat shield on the floor pan. Its held in with a handful of selftapping screws and overtime they fall out allowing the sheetmetal to touch the exhaust

 

to a glance, the shield above the cat is kinda tore up looking. The tailhousing does hit the car when i press it hard and the rattle only happens when i accelerate, not at a low cruise.
Also what what pumps are there to a transmission?

 

Sorry im kinda retarted from hitting my head alot in high school fotball
Whats the TV Cable and how would i adjust it?

 

Trans main pump is driven by the converter. Sort of like the oil pump on your engine

Grab a new trans mount and reattach the heat shield

TV cable controls line pressure in the trans based on how much throttle you're giving the engine. If its out of adjustment your shifts will be early/late/hard/soft and the trans may feel like its slipping. Running it like this for extended periods WILL burn up the trans. Dont adjust the cable unless you need to. If its shifting fine before, leave it alone

 

How would i come to find the trans main pump? i wanna see how it's working.

well my trans has a soft shift and it's always late.
could you instruct me on how to adjust it to the proper manner? to where the rpm's are correct and it's not so late at shifting?

 

https://www.thirdgen.org/detent

 

thanks ill try it once it's day time

 

I had a similar sound in my Suburban. Found some loose bolts for the flex plate. Just a thought.

 

hey man, did you ever find out what it was? I'm having the same rattle under acceleration. I did find that my tranny mount was broken. I'm replacing it in the morning. The rattle seems to happen mostly around 500 to 1500 rpm especially when the motor is under load, like leaving a light on a slight grade under light acceleration.

 

check the header to exhuast clamps/connectors..always come loose on my bird.

 

thanks for the suggestion. I'll definitely check that today. Now that I think about it, it does kind of have that kind of a sound to it.

 

did you ever find out what was causing this noise, the same thing is happening with my 92 rs right now

 

yeah i did. I did have a BUNCH broken clamps or rusted out clamps on my exhaust. But I also had both my engine mounts broken, transmission mount broken, both universal joints broken, and rear end links broken. So eight hours later, no more rattle. But if I had to choose one thing that Itruly believed was causing the rattle, I would say exhaust.