Tranny slipping in high gear

Please someone help me. I have a 2001 Grand Am SE V6 automatic. I just paid a grand to have the head gaskets replaced. But the guy who fixed that can't figure out what is wrong with the tranny. It only slips in high gear, and then the rpms go way up, but the car don't go faster like it should. The car has 80,000 miles. He said it could be the Overdrive Celnoid(sp) but isn't sure. Does anyone else have this problem. Can someone please help. Also my wild 20 yr old son was driving the car for about 6 months and he says the tranny is slipping in all gears. But I tried it out, and only slipped in high gear. Thanks to anyone that can help. Oh yeah, another thing, how do you check the level of transmission fluid in this thing? All the book says is to take a to a dealer?? Why can't we check it?

Welcome to AF!

There is a possibility that the solenoid that engages the overdrive gear is not properly engaging the overdrive but I don't think that is your problem. It is also possible that the transmission is low on fluid. For some reason GM did not put a dipstick on the Grand Am transmission although if you look at the very top of the transmission very low you should see what looks like a small red plug. That is where you check the fluid. If you find that it is low on fluid that could be causing the issue with the slipping but you need to get the transmission checked by someone with a trans capable scanner. A good transmission shop can do this for you. You also may want to have the fluid and filter changed as it may be due to a clogged filter. One thing that may help if the trans is just low on fluid is to put in a can of Sea Foam transmission additive. Available at Autozone. Will help to clean and lubricate the trans better. Do not let anyone talk you into flushing the transmission as you will need to have it rebuilt shortly thereafter. I hope this helps!

Thanks for all the information. But how do you know if the level is low where the red plug is, should we use a ruler to check, how far should it be? My dad is helping me with this issue, and he said he has taken off the plug, but doesn't know how too tell if it is low?

Thanks for all the information. But how do you know if the level is low where the red plug is, should we use a ruler to check, how far should it be? My dad is helping me with this issue, and he said he has taken off the plug, but doesn't know how too tell if it is low?

The following link has the procedure to check ATF fluid on a GM 4T40E/45E autotransaxle:

http://www.quality-trans.com/faq/faq8.htm#41

I brought my Grand Am into a transmission shop, oh and big surprise, they said it needs a new tranny, $2600.00. On 80,000 miles?? I am going to have some other opinions, or the car will sit until it is paid off. Any other suggestions on my tranny slipping only in high gear when warm would help?

First of all getting a second or even a third opinion is a good idea. If all three say you need a new transmission, check with the local wrecking yard to check the cost of a used transmission. Some of the wrecking yards even install transmissions and engines. It will be about a third of what it will cost to have the tranny shop do it. You may even be able to find one on e-bay that will fit and have it shipped in. A lot of wrecking yards have stores on e-bay with reasonable prices.

I would try the fluid and filter change along with a can of sea foam additive before doing anything else. It should cost less than $100 and may save you a whole lot of money or at least buy you some time before a replacement is necessary.

I agree with GTP Dad on the fluid and filter change.
And if that doesnt fix the trouble, get a second and third opinoin on whats really wrong. Good Luck