I have just had my 700R4 rebuilt [fried the 3/4 clutch pack] and now I can't manually hold the trans in 1st gear.

Before the rebuild, I could hold the trans in 1st as long as I liked until I hit the redline and then it would shift itself into 2nd. Now if I hold it in 1st at part throttle, it just shifts itself into 2nd. What gives?

 

Well if it was rebuilt I'm assuming you took it out yourself and put it back in? Check the adjustment, you're probably not adjusted correctly so when the indicator says 1st your actually in second. I've never worked on a trans-plant.... Pun intended....so I'm not sure how to adjust the linkage but it most likely needs it. Check that first.

 

Was this a "rebuild", or was it REALLY an "exchange"?

Maybe the one you took out had a shift kit in it, and the one you put back in didn't.

 

That's what I was thinking. Without a shift kit, the tranny will automatically upshift at a specific governor speed or line pressure in relation to throttle position. A shift kit can bypass this feature and allow you to hold the tranny in gear until you either manually shifted or hydraulic pressure is high enough to force a shift.

 

No the trans was rebuilt - I'm in Australia and the transmission guys here are familiar with 700R4's because the earlier Holden Commodore's used them but there are slight differences. That means that an exchange transmission is not really a possibility.

So does a standard transmission not hold 1st?

 

Hmm. Ive always been able to hold even stock 700's in first.