'94 T-Bird Transmission prob.

I have recently purchased a 1994 T-Bird 4.6 LX (from 2nd hand dealer here in th UK). Previous owner mentioned gearbox "rumble" when he traded it in to the garage, but said that it'd ben fixed. Bill of £1200 mentioned. Great, I thought. Box has been rebuilt.

Driving car home yesterday from the garage, and the transmission (I think) does what I can best describe as a rumble/vibration every now and again, normally when it is about to change up, or down. It sounds like you are driving over a "rumble strip" in the road. It lasts for about a second or two, but you can get it to go for longer if you are careful.

Appart from that, the car drives really well. It has done a genuine 46000m.

Garage owner said that he'll get it fixed for me (for free). I know him quite well, and purchased my other car (87 Firebird) from him, so I'm sure he means it.

Can anyone tell me if this is a common problem with T-birds, and give me any idea what exactly it could be. ie electronics, throttle position, vacum or gearbox internal problem???? What gearbox exactly is it thats fitted to the 4.6LX's in 94?

Any help would be much appreciated. I don't really want to take the car back and get a different one. I figured I'm buying a legend, as they've been making them for 50yrs!!

Thanks,

Andy

Could be as simple as a flush and fill with Mercon V and a new filter by the symptoms you describe. The transmission/gearbox is a 4R70W.

Thanks for the reply, I drove the car around a bit today, and have established that the "vibration/rumble" happens at around 13-1400rpm. Its almost like when you pass through that band, particularly when accelerating gently, you get a vibration just for a second, but if you are on a hill and can keep it at that rpm it will keep going.

I'm beginning to wonder if its a missfire type problem. I know what a missfire on a 4 cyl engine feels like, but have not experienced it on a V8. Maybe its the throttle position electronics?? Des anyone have any ideas???

See Chapter 4 - Common Problems - Torque Converter Shudder (see TSB#98-8-7)
Ford Overdrive Transmissions 101 (http://www.tccoa.com/articles/tranny/transmission/index.shtml)

Techincal Service Bulletins for 1994 Ford Thunderbird V8-281 4.6L SOHC (http://www.tccoa.com/articles/misc/tsb/tbird/94-46.htm)

Thanks JR. I have never come accross that club before, but having had a look at the technical info for the tranny, I'm hoping mine's just been filled with the wrong fluid.

Its going to a tranny specialists later today, so I'll keep you posted.

Andy

well i have a 94 thunderbird.. great car..
i had a simular problem and it is due to the stall converter ...if it is the same thing i had wrong i was told although the car may run good it may be missing a little causing the car not produce enough power to unlock and lock the stall converter(aka converter chatter)does it do it on the highway....
i threw in a set of spark plugs and wires and it fixed the problem.......hope this helps

read the TSB link tigerstar put up, its a common problem in these things

I've had the car checked by a gearbox specialist, and they are fairly sure its a torque converter problem. We're going to try flushing and refilling with Mercon V tomorrow, and we'll see if that does the trick. Unfortunately I found out yesterday that the car may have been doing this for a year or more, so I'm not holding my breath as the gearbox guy said that it may have damaged the friction plates in there somewhere.

Fingers crossed!

Bad news I'm affraid, when they got the sump off the gearbox, there were lots of metal fillings stuck to the drawin plug. Refilled it with Mercon V and its exactly the same.

Luckily the dealer I got it from has agreed to get the box rebuilt/repaired for me at no charge. They are collecting the car tomorrow, and I can't wait to get it back!

Phew!

Be sure they use the updated accumulators & springs and put in a NEW torque converter.
Also, this would be a good time to add an external transmission cooler.
Read over Ford Overdrive Transmissions 101 (http://www.tccoa.com/articles/tranny/transmission/index.shtml)

Update: Had car checked out by second transmission specialist yesterday (choice of guy I bought car from, but I have used company before). They dropped sump and change a couple of valves/solenoids, refilled with dexron+additive, and hey-presto, it works perfectly.

I am at a loss as to why my preffered co didn't find this (pissed of the guy I bought car from as he nearly forked out £1300 for a box rebuild!), but it definitely seems to be fine now. Time will tell I guess.

one thing I'd like to know - if the box starts shuddering again will it suddenly start at full force, or does it come on gradually over a period of time and get louder/harsher as time goes on??

Thanks for all your advice.