Hi, own C5 since last year september and gearbox worked perfect. Drove maybe 200 miles till november and placed in to garage for winter. After it, there's no second gear. I should gain 2 - 2,5k rpm than release gas pedal and it shifts to 3rd gear. 4th gear works. I want to beleave nothing sirious... maybe something could stuck, or some seal could degrade after winter? Servo KIT already done. What else to check?

 

You should clarify what you mean by no second gear. Is the shifter being blocked like the shift solenoid is stuck or does it go into gear and nothing happens.

 

shifter it self is not blocked. It goes through all the positions from P to 1. Gearbox just did not engage 2nd gear. Gearbox can go through all gears 1st, 3rd, 4th up and down, but skips 2nd. When accelerating, I should gain 2 - 2,5k rpm in 1st gear and gearbox goes straight to 3rd gear, than to 4th. While downshifting, gearbox goes from 4th to 3rd and from 3rd straight to 1st. If I'm driving in 3rd gear and put a shifter in 2nd position engine turn freelly like in neutral.

 

That doesn't sound like anything you're going to be able to fix on your own.

 

What happens when you start from a stop with it in second gear?

 

Beat me to it! Yes, try starting from stop in 2nd gear. A lot of rear wheel drive GM cars back then, including the C5, had what was called 2nd gear start. It was intended for low traction conditions (ice and snow). Car should move. OP could try a trans flush product. If it doesn't change anything, pull the pan and replace the fluid and filter.

 

Didn't tried yet. definitely will try.

 

Do you have a good reverse?

 

I'm not a professional, but yes. I would say - all perfect with reverse, 1st, 3rd and 4th gears, except no 2nd strange thing, that 2nd gear disappeared after few months of storage in dry garage... at the moment I think of disconnect/cleen/reconnect all electrical conectors on the gearbox (have sence?), and than drop the pan, new filter/oil, also inspect A solenoid and for stuck valve.

 

I was asking because no reverse and missing some forward gears is a symptom of a broken planetary gear cage problem I had. The diagnostic tree is VERY short. LOL!!