Thread: 99 3.1L no overdrive, please help.

4th gear is gone, the shaft splines are gone. Pretty common issue.

Either do a full rebuild or tear it apart and put in a hardend 4th gear shaft, but I assume its got higher miles so a rebuild is better because the rest of the trans is worn aswell.

The 4T60e was only in a 97 for the Grand Prix cars.

Its a 4T65e, you can buy a shaft from various companies that sell 3800 parts.

You don't have a broken band, the 2 bands inside the trans have nothing to do with 4th gear.

Read this, if you want further info. It will show you that I know the issue.

4T65E Common Problems

Either way even if the the 3.1 motor option got the vacuum controlled 4T60 the problem is the same.

4th gear is gone, forever.

No idea on weather those parts are compatible.

The trans has 1 forward band and 1 reverse band, if the band snaps you lose Drive, but can be put in 1 and 2 manually and move the car, same goes for Reverse, band breaks and its gone.

Can you please toss up a pic of the top of your trans, I thought all GP's including the 3.1's all got a 4T65 starting in 98. Would like to see if for ourselves kinda thing.

TMK the 4T60 was not known at all for this issue. Having been on a forum with about half 60's and half 65's the 60 guys would make fun of the 65's based on the PCS and 4th clutch hub.

The splines only get destroyed on the hub shaft, not the other piece that it slides into.... now that I'm thinking about it, I can't remember what it slides into. It's not the third sprag, It's closer to the side cover. Either way..

Since we are talking 4T60, I'd be more inclined to think this was a set of 4th gear clutches before a hub shaft. They are actually easier to get to than the hub shaft. Search on 4th gear shaft and my screen name to find a how to with pictures of the 4T65. The 60 is nearly the same transmission.

My 4t60e is off of a 97 grand prix with a 3800 NA.. The 4t60e was available for the 3.8 NA until 99, and was almost exclusive to the 3100.

If you were closer I'd give you a great deal on a used tranny. But I dont think you'd be too interested in driving more than halfway through NY state to get it lol.
On the right side of the chain you'll find 4th gear clutches and hub shaft.. This is after taking off the channel plate and valve body. These pics are from the 65e-HD trans.. The 60e may be different. Not sure.



Now you take off the clutches and pull the shaft out, the end looks like this. This is what causes no 4th gear/overdrive.


I'm fairly certain the 4th shaft slides into the sun gear at the top of the 3rd gear/input drum. But don't quote me on that. If I get bored enough out here I might rebuild the 4T60E just to see how similar they really are.

Hope this helps

Here's one link. I think there's two.
http://www.grandprixforums.net/how-t...ess-54448.html

Found a link for which transmissions were available in which year/engine cars. I had never heard before that the 4T60 was available 98-99. Since I haven't looked at 3100's much, I dug in. 3800's did not have it available after 1997, only the 3.1 motor could have the 4T60 until 99 in the Grand Prix. Learn something new everyday!
Automatic Transmission Application Identification

PM me your email address. I'll send you the 4T60 manual.

Usually I'd say do X or Y.. reality is..there are some small differences 65 to 60 and I've never overhauled a 60 to tell you if there's something odd on that shaft.