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The transmission went out at highway speed. I shut the car off and it drove and shifted fine for about two miles and then did it again. It does not slip, it just goes out. After doing this 4 or 5 times it quit going into gear completely but after getting it home by pulling it ,it shifted fine again. The fluid is fine and not burnt. My son went into the ditch with it a couple of days ago. I am wondering if there is something that may have pulled loose that would cause this. It seems like a limp mode but that usually leaves you with one gear to "limp" home. I will point out that when I bought the car , it skipped 3rd gear and went directly into OD. I never tried to fix it since if I didnt accelerate hard, the only way you could tell was by the tach.

Thank you,
Pat
Hi Pat,

What engine? How many miles? Is the "Check Engine" light on?

The best place to start is a scan with a Full Function scanner. Most code readers won't get into the transmission codes. Record all of the code NUMBERS, post those numbers here for review & have the computer cleared.

I am guessing that you have a bad shift solenoid. If I remember correctly, reverse wouldn't work if 3rd gear was actually out? But it has been a long time since I was into a transmission.

Please get back to us.
Would agree with Garner on needing more info but in addition look around for physical damage as part of your diagnosis. You never know if it's a pulled / pinched harness, cable, dented pan, binding linkage, crimped lines, etc.
I have a shop close by that can scan for me .I just have to get it there. It may take a couple days. Engine light is on and has been since I bought the car. Engine is a 3.8l. Checked everything top to bottom and nothing seems out of place. I will post codes when I get them, thanks
Sorry for the delay. Had it in the shop today. We pulled 3 codes ... PO741, PO742, PO756. The first 2 are TCC codes, the last said something about a valve or something. They all pointed to bad news internally. I did some reading on these transmissions and came to the conclusion that if it was not completely shot and even if all electrical was removed or bad, it should still have 2nd and reverse. I pulled the pan today and found what was left of 3rd gear parts in the pan. The filter weighed heavy and was plugged. I cleaned everything, replaced the filter and fluid. It works like brand new, other than still not having 3rd gear ( which has been missing for about a year) It shifts smooth and doesn't slip a bit. My question is how long will it last? I forgot to mention that the previous owner replaced a cracked housing (axle I think) because he thought that had something to do with it. Maybe the debri came from that and the shift solenoid is just bad. Anyway, it seems weird that, with what I dumped out the pan, it should even work at all.

Thank you,
Pat
With that new information I am still thinking that 3rd gear is probably OK. I am pretty sure that 3rd & Reverse go out together with a mechanical failure. Since you have Reverse, 3rd should be OK too. It sounds like the Torque Converter Clutch (TCC) is out and that would be the debris that you found in the pan & filter. It would be ground up and burnt clutch material. This stuff also travels through the valve body & plugs things up. It has likely plugged up the 2-3 Shift Solenoid and that is why you don't have 3rd gear. You could probably fix 3rd by pulling and cleaning the valve body. However, the Check Engine Light will remain on because you won't have lock up. For the amount of work involved in that I would probably just pull the whole thing, replace the Torque Converter & have the transmission rebuilt.

How long will it last? That is anybodies guess. With the debris in the valve body, skipping a gear & no TCC the odds are against you. When it does go & breaks things inside it will cost a lot more to fix.

You can read the code meanings here:

Code P0741: engine-codes.com/P0741.html

Code P0742: http://engine-codes.com/p0742_gmc.html

Code P0756: http://engine-codes.com/p0756.html

Thanks for the updates. Good luck. Please keep us posted with anything new.
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