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Went to replace the speedometer driven gear due to speedo/odometer not working and discovered that the speedo drive gear spins freely by finger when I inspected it. I’m guessing this shouldn’t be the case??? I’m thinking the retention clip on the drive gear isn’t working as intended. Since I don’t have a removable nose cone on my thm 200 c I’d have to drop the transmission and do a whole lot of work to replace this bugger which I’d like to avoid. Anyone else come across this issue? Thoughts/suggestions??? Thanks much.
I assume the driveline is not spinning when you spin the speedo gear? If yes then your assumption would seem correct. Gear or retention clip is likely broken. I am not familiar with the 200, but on the 700 you remove the tailshaft housing and the gear is readily accessible.
Thanks GD. You're right, drive line does not spin when I move the drive gear with my pinky finger. Thank your lucky stars you're not familiar with the Thm 200 C. The case is all one unit with no nose cone as far as I can tell, so to replace the drive gear the tranny has to come out and all guts removed in order to access the drive gear/retention clip. Brilliant design GM.
If you haven't dropped the pan to see if there is any access towards the output, you might try.
If I recall correctly, the TH200-C TCC solenoid requires dropping the trans. to pull the pump to replace it also.
Seriously, a 200-4R or 700-R4 makes sense, is nearly bolt-in, and will improve mileage.
I know the on 200 4r you can drop the pan to access the governor/speedo gear as the are all in one. Can anyone tell from the diagram on page 4 (attached link) if I need to drop the trans to replace the drive gear or access it by removing the pan on my 200C?
Thanks for all the advice. I’d love to update the entire driveline and a few more things to make it a Pro Touring Pace Car- but I’m not one to do that kind of serious wrenching on my car and it wouldn’t really be cost effective to have someone else do the work. But it certainly is tempting. And then there is the fact that the rebuilt 3 speed in it actually works really well, aside from the speedo drive gear hiccup, and is original to the car. Decisions, decisions.
Thanks for all the advice. I’d love to update the entire driveline and a few more things to make it a Pro Touring Pace Car- but I’m not one to do that kind of serious wrenching on my car and it wouldn’t really be cost effective to have someone else do the work. But it certainly is tempting. And then there is the fact that the rebuilt 3 speed in it actually works really well, aside from the speedo drive gear hiccup, and is original to the car. Decisions, decisions.
With everything you said in this post considered , I like the GPS speedometer option (if , of course , your budget allows)
You won't get the speedo gear out through the pan or a new one put back in. You also won't get the drive gear out through the output slip yoke bushing; gear is too big. I was just hopeful you'd be able to slide the gear out of the way, hold the new clip with a magnet or clip tool from either pan-side, or speedo gear hole side, and slide the speedo gear forward or backward onto the clip. I don't have a 200-C to advise further.
If you do decide to swap, the 700-R4 from a hi-performance option IROC, Z28 or T/A tends to have a nicer shifting valvebody than one from a Caprice. The same can be said for the performance G-body 200-4R models.
