Transmission shifting roughly

The thunking noises for the back of the car wouldn't be related to the trans-axel transmission. If your problem is hard shifting and the fluid level is at the proper level then I wouldn't recommend paying to have the fluid changed, chances are it won't make a difference. Are there any check engine codes on your dash? This could indicate a problem with part of the transmission. unfortunately, your car is starting to get high in mileage and if the transmission wasn't serviced properly every 60,000 miles or so it may have permanent damage. Check your fluid level, check any OBDii codes. You may have to replace the transmission. Changing your transmission fluid is just like changing your oil, every 3,000-5,000 miles you change your oil, every 30,000-60,000 miles you change your transmission fluid depending on the type of car.

Yes, and I had bought this car at 151,000 miles so I do not know how it was maintained. I haven't checked for any codes, I hadn't thought to do that and I do not have a code reader. I had thought about getting one but I hadn't found one for a '95, I think maybe O'Reiley's might do that. The is no "check engine" light on. I was not aware of changing the transmission fluid every so many thousands of miles, so thank you.
What would a thunking from the rear end of the car be?
Next time I'm out in it I will try to pay even closer attention.

The major local auto parts stores will read codes for free, like you said there aren't any codes displaying on the dash so it's a good chance we can rule out any faults there. If you can get a good flashlight under the car you may be able to see something easily noticeable that looks disconnected in the rear end. Possibly part of the suspension or exhaust system has broken off, It could be a number of different things. Going back to the transmission, keep in mind that keeping the fluid at the proper level and changed in accordance with the manufacturer's recommendation is very important in its life. The car had relatively high mileage when you got it so yeah, it's hard to say if it had ever been changed. Good luck and let me know if I can help with anything else.

I did check the transmission fluid again today and noticed bubbles on the dipstick. Does that mean anything? It was full, not overfull. :-)

The check engine light isn't on, is what I meant, so I hadn't thought to have the codes read. I may have that done when I'm able.

Thank you.

I just happened to think. I was told that the PCM or is it the ECM, the computer module behind the glove compartment might be bad because the fans start when I turn the key on (the short of it) would that have any bearing in this case? Could that cause this sort of problem?

I wonder this in part because it is "intermittent", sometime it does, some time it does not. I'll await your answer. :-)

Hello, I'm Danny.

Since you don't know the vehicle history you should assume the car was neglected. The mileage isn't all that high so the transmission might not be in all that bad of shape. Use a white paper towel to check the transmission fluid level again and look at the color. Is it brown or dark in color? Smell the fluid as well. Does it smell burnt? It normally should be clear red in color when fluid is in good shape. You mentioned checking vehicle codes. You don't need to use a code reader or scanner if you don't have one because a paper clip or piece of automotive wire will suffice. Here is a tutorial showing how to check codes on your car which can include transmission codes:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Also, you mentioned a clunking sound. When it comes to sounds they are hard to diagnose without being by the car in person so what we ask is to use your cell phone to make a video and upload here for us to listen to. After you check for codes get back to us with any information and we'll go from there. Hope this helps and thanks for using 2CarPros.

Believe it or not I do not have a cell phone nor do I want one so that would not be possible.

Hello again.

Okay, then just get back to us after checking the condition of the fluid and checking for codes and we'll go from there. Hope this helps and thanks again for using 2CarPros.

Danny-

I did go ahead and change the fluid and filter, another man's recommendation. The clunking and noise is gone, the car is shifting smoothly as silk. The fluid wasn't too dark and did not smell burnt. Thank you for your help.

You're welcome!
Thanks again for using 2CarPros and we hope you will use our site again in the future.

Danny-

Sir, I looked at the "plug in" for the OBCD1 plug and it doesn't match the diagrams you'd given me access to. The reading said before 1995. Mine is a 1995, I guess that's why they didn't match up. In the two plug ins where it said to put the wire one had a silver connection in it, the other one had nothing. Is it messed up or would a diagram for a 1995 help? I do appreciate the help you've given me.

Hello again,

Since this is not transmission related the proper protocol is for you to start a new question for an OBD1 issue. Here is the link:

https://www.2carpros.com/questions/new

Be sure to include all your vehicles information and the OBD1 question. Once we receive your new question we will be happy to help. Hope this helps and thanks again for using 2CarPros.

Danny-