Lost 4th gear today. Questions and help.

[suitercrew]

Hey guys I recently lost 4th gear. I know this is a common issue and I only drive on the highway once every other week so my question is. Firstly does loosing the 4th clutch hub throw broken parts in the transmission that could grenade and destroy other parts in which case I should flush the fluid immediately? Second question, the 4th gear going doesn't necessarily mean any other parts are close to failure right?
The car in question is a 1999 Grand Prix with 4t65e non hd. Approximately 125k miles. Fluid was flushed at 100k and looked great.

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[BrandonHall10]

Run it.

The shaved metal from the hub splines will most likely get stuck to the magnet. If not, the filter will snag them.

[wstefan20]

I would change the fluid and filter at the minimum. It does send metal fragments through transmission, and since I think its lubrication point feeds though the output shaft, but it might go back to the pan before causing much harm. I've known people who have driven without 4th for a long time. Too bad you're not closer, I'd offer to rebuild yours for you. I would absolutely avoid driving at high speeds.

Oh, and I'm sorry to hear the trouble! Love your build so far!

[Mitch R]

I had a Lumina without 4th for a long time. Put at least 20k highway miles on. I limited my speed to 60, and 65 in a pinch though. The rpms are high and you will lose some mpgs, on the plus side it never had any problems climbing hills with the cruise set. Silver linings lol.

[suitercrew]

Ok thanks everyone for your advice. It's good to know that It shouldn't be anything needing immediate repair.

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[BillBoost37]

I would agree on run it. But ... that hub will start to trash the er uh...Brandon...which piece does it go into? that piece can get beaten up as well.

$40 plus fluid and some time.. you can switch that part out pretty easy in car

[suitercrew]

I would agree on run it. But ... that hub will start to trash the er uh...Brandon...which piece does it go into? that piece can get beaten up as well.

$40 plus fluid and some time.. you can switch that part out pretty easy in car

Ok thanks everyone for your advice. It's good to know that It shouldn't be anything needing immediate repair.

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[suitercrew]

I would agree on run it. But ... that hub will start to trash the er uh...Brandon...which piece does it go into? that piece can get beaten up as well.

$40 plus fluid and some time.. you can switch that part out pretty easy in car

Ya I don't care about replacing it. I only drive on the highway literally twice a month so as long as it's not going to destroy the rest of the transmission I can live with the few mpg lost twice a month.

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[BrandonHall10]

I would agree on run it. But ... that hub will start to trash the er uh...Brandon...which piece does it go into? that piece can get beaten up as well.

$40 plus fluid and some time.. you can switch that part out pretty easy in car

It's been a while since I've been elbow deep into one of these. I want to say the 4th hub mates to the dual sprag assy. I think (but I could be wrong) that the 4th hub shaft is also guided/supported by bushings on both sides. So it's not like, once the splines are gone it's flopping around. It's just free wheeling in space. Either way, I wouldn't be super concerned because that 4th clutch hub is butter soft and the sprag assy is mildly hard. Like banging a banana inside a drain pipe.

When you're ready for a decent rebuild, drive 2-1/2 hours south and I'll take care of you.

[BrandonHall10]

Or just replace the hub with the trans in the car. Should be able to do it on a long Saturday. I know there's a good write up in the how to section.

[BillBoost37]

It's been a while since I've been elbow deep into one of these. I want to say the 4th hub mates to the dual sprag assy. I think (but I could be wrong) that the 4th hub shaft is also guided/supported by bushings on both sides. So it's not like, once the splines are gone it's flopping around. It's just free wheeling in space. Either way, I wouldn't be super concerned because that 4th clutch hub is butter soft and the sprag assy is mildly hard. Like banging a banana inside a drain pipe.

When you're ready for a decent rebuild, drive 2-1/2 hours south and I'll take care of you.

Been a while for you.. it's been twice as long for me. I think you are correct and I remember one or two guys saying they did the shaft and still had an issue. Dave from TEP hopped in and said that the part the shaft engaged had likely also gotten beaten up from the long term. It's not common and you can feel it when you put the new shaft in.

2.5 hours....I'd cruise on down to Brandon ... even if just to replace the shaft in the car. He's great with these things and he would be welcome to work on mine if I still had one. Also.. 4 hours is doable for a swap, ask Scottydoggs. hahahahahaha