[Mister Pontiac]

Thanks Gents. It's a fun adventure with Bonne.

Matthew, thanks for the thought, but I'm going to stay with the TH400. OD isn't really needed with the 2.93 rear with my usage, and I don't want to give up the strength of the beefier TH400 vs the 700R4. If I were to upgrade, it would be a 4L80 or maybe a Gear Vendors, but either of those options would be a $40 saddle on a $10 horse. Heh.

And speaking of the Turbo 400, I've had an interesting one with her lately...

A while back, the speedometer stopped. I was hoping for an easy broken speedometer cable, but it was actually the speedo drive gear on the trans tail shaft that had come loose from its clip. Odd.

I pulled the tail housing, reinstalled the clip, and down the road I went. For about 1000 miles. Repeat.

Hmmm...

Out of curiosity, I ordered a new drive gear and clip, then pulled things apart again today. As I looked at each piece in detail, I realized what I think is the problem. The pics tell the story, but essentially, it seems the original drive gear (tan) has 'swollen' somewhat (about 0.025" ID and seems a touch wider too) causing it to not sit snugly over the tail shaft. Given the right set of circumstances, it twice popped loose from its retaining clip and spun away from the driven gear.

Today, I installed the new drive gear (green) and clip, and now it's nice and snug. I think I've solved the problem and don't anticipate any further issues. This was an odd one to me, but an easy fix once I realized what was going on.