Ford T-Bird Transmission Problem
 

I have a 97 Ford T-Bird that in the last couple of days the transmission has started to act up. When the car shifts into 3rd gear it "shudders". If I let off the gas for a second or two all is fine when I accelerate again. Also if I accelerate a little faster then normal there is no problem. Any ideas out there, I don't want to go into the shop with no idea what it could be.

What motor, is it auto or manual?

Opps. Its a 4.6 V8 with an automatic trans

First off.... how long has it been since the filter and fluid have been changed? Check the fluid level, color and odor. If fluid is low, top it off and see if things improve. If the fluid is any color other than bright red, get it changed, along with the filter, immediately. Does it smell burnt (don't worry... you can tell)? Get it changed!
If all is well with the fluid and you still have a problem... it's trans shop time.

Ford's recommended fix for third-gear shudder (around 40mph, I'm guessing) is to change the filter and fluid, using 100% Mercon fluid. After replacing the filter, flush out all fluid, including in the torque converter, by disconnecting the fluid line at the radiator (the one that brings fluid out of the transmission) and run the car in park until it's dry. Pour through a quart to clean it, then reconnect and fill.

I have also managed to correct the problem by staying out of the 39-43mph range, and using a lead footed approach approaching that shift point.

I'm not sure if that's a symptom but those tranny's have a history of problems with some piston that wears the piston sleeve causing it to "rock" in it's sleeve. Rebuilding or replacing was the only cure that I knew of 3 yrs ago when I did used car recon. I hated it when they took those in for trade in or bought them at the auction. One out of three gave me tranny problems.

MrSelfDestruct got it. Ford released a new type of fluid called Mercon V made specifically to address that problem. You'll want to get a complete flush (the kind where they hook up your car to a machine that pumps all the fluid out, dropping the pan only gets about 1/4th of the fluid).

The problem Krycheck mentioned is the 1-2 accumulator, when it goes bad you'll get a very hard or delayed 1-2 upshift. Fortunately it's easily changed by most any mechanic, the part only costs a few bucks and it can be accessed simply by dropping the pan.

These trannies also like to randomly drop into neutral at highway speeds, which is the result of a sensor getting water in it, shorting out, and telling the computer you shifted it into neutral. There's an updated part with an improved seal.

The 4R70W isn't the best tranny, but it's fairly robust if you maintain it well and address those problems as they crop up (if not before) as they can lead to further damage if you ignore them.

Just to update. I took MrSelfDestruct's advise and got the fluid pumped out and change using Mercon V and the problem went away. Thanks for all the help

WOOHOO, I fixed something over the internet!