Hello, first time user of the site. Looks like there is loads of information and people who know their stuff on here. I don't know much about cars, and I'm hoping that someone can help me out here.

My 96 Deville is showing the Service Transmission light. It idles hard (like a chugging sound, almost like its skipping a beat) and it slips a little bit when changing gears (2nd and 3rd gears, I think). I have to drive from LA to Iowa in a little less than a week, and I'm worried about getting stranded in the desert or Rockies on my way.

Being the idiot I am, I have been filling up on regular gas for the past year. The guy I talked to at the shop today said the check engine light could be because of emissions or an O2 sensor, so I'm wondering if the gas could be what caused the problem? Or do you guys think I'm going to have to bite the bullet and get the whole damn tranny replaced? If so, approx. how much would that run?

Any advice would be appreciated!

i'd take car of any tune-up items, and routine maintence first, if all fails then you can worry about replacing your trans

I also have a '96 Deville. Others here will tell you that it is fine to run it on regular gas, but my experience has been that the quality of the gas is the main difference. I used to always go to a gas station near wear I worked becaue they sold premium gas for the same price as regular and I was constantly getting the emissions codes/service engine soon light and with my engine idling rough. When I switched to higher quality gas the problems disappeared.
The service tansmission message is an entirely different matter. I'd say..and I'm no expert, but if you're having slippage..you should bring it in. In the past my experience (with other vehicles) has been that once the transmission starts to go..it goes quickly.
I'm surprised nobody has mentioned this yet..but you need to pull your codes. Once they have codes..the guys here are awesome : )

Regular gas is not your problem and it will run just fine on it. Does the trans fluid look brown and smell burnt?

Thanks for the tips everyone.

"I'm surprised nobody has mentioned this yet..but you need to pull your codes. Once they have codes..the guys here are awesome"
--I'm not sure what you mean by codes.

"Does the trans fluid look brown and smell burnt?"
--I tried checking this, but I can't even find the fluid...Like I said, I'm an idiot. I'll try finding it again tomorrow.

If you are facing the nose if the car it is to the right of the engine under the intake tube. Red cap with a short dipstick. To check the level you need to have it running in park after about a 5-10 mile drive at least(needs to have the trans warm). The fluid ideally looks like red Kool-Aid (or Flavor Aid depending on demographic). If it looks brown than it is not good. I don't really recomend a flush, but dumping the fluid and changing the filter now and then in a couple of weeks again would be a good idea (the cleaners they dump in the trans witha flush may do more harm than good in your case). Pull your codes and report back and these guy will give you some good advice.

Thank you, I'll check it tomorrow. How do I pull my codes?

A few months ago, my "service transmission" message came on. I had a heck of a time trying to find the dipstick, too..it's kind of hidden.

http://www.cadillacforums.com/forums/cadillac-deville-1985-2005-including-1985/138257-how-pull-codes.html

Or if that doesn't work there's a sticky at the beginning of this forum on how to pull codes.

Good luck

As mentioned the trans fluid cap & dipstick are under the intake duct. Unplug the IAT sensor. The loosen the clamp on the TB. Grab the entire air filter box from each side and give it a good jerk. Rotate the entire assembly up and toward the windshield. Now you'll have access to the trans fluid cap.

Don't let anyone flush the trans. Just drain and refill. Read the Technical Archives at the top left of this page and follow minnesota's advice on the DTC's.

Ok, awesome. I checked the fluid and it was a dark red color. It was more red than brown for sure and it looked very low. I did the code thing and it told me "TRANS FLUID RESET"

I'm going to get my oil changed and my transmission drained and refilled. Hopefully that gets me 1800 miles. Any other advice? I really appreciate all the help, and you guys have a fine site here. Thank you very much!

I got a 96 deville and had to replace tranny at 62000 miles. If tranny is low, you are burning fluid due to band slipage if you don't have a leak

turnerbend has a good point. Transmission fluid is supposed to stay in your transmission..if it's very low..that means there's a problem...I would definitely have that at least checked out before you head out. also, I'm not so sure that "trans fluid reset" is a code. The first time I tried to check codes..I accidently hit the wrong combo of buttons and got that message. It should run through a series of messages as it checks the system. If it didn't do that, I'd try again.

Ok, new info. I had my transmission fluid drained and replaced, a new filter put on, and my oil changed today. The guys at the shop say that there is no transmission malfunction at this time. However, they gave me two codes: "P0717 - Input Sensor" and "P0305 - #5 Cylinder." They said if the input sensor needed to be replaced, it would require a transmission removal.

The check engine light went off initially, but came back on about an hour later with the same Service Transmission message. I'm taking it to another guy that does engines tomorrow. What should I expect?

The input sensor is inside the side cover. Technically, the trans (drivetrain) does have to come down, but there is a way to lower it just enough to get the side cover off and replace it in the car.

I'm going to give it a go and have everything looked at in IA. Wish me luck. Thanks for all the help.