Why does my 1997 Thunderbird transmission shudder?

Answer 1

In the late 90's Ford started haveing problems with there transmissions expectaly the automatics. The problems are with the way gear's are spaced the seperaters were not milled with the proper specs and started to wear prematurely causeing the transmission to shutter at different speeds but mostly when brakeing because of the slack in the transmission when the power is not being applied.

Just for another point of view, I am a longtime Thunderbird owner (1992, bought new) who started having a problem with a jerking sensation under certain conditions - mostly when accelerating or going uphill. It often happened when the transmission downshifted. Having had long experience with repairing cars, it seemed to me like an ignition problem. Remembering that the spark plugs had been in use for over 100K miles, I changed them. That appeared to fix the problem - for five days. Then it came back (should have been a clue). I did note that the gaps on the old plugs were quite wide (.070 or so). Anyway, I subsequently replaced the plug wires and distributor cap without result.

A guy I work with suggested a new fuel filter - but that didn't help. I took the car to a local garage - who kept it a week and failed to diagnose the problem. Fortunately, they only charged me their normal diagnosis fee. Then I found an "Expert" consulting service on the internet, and availed myself of their services. A retired Ford Master Mechanic diagnosed my problem (based on my description) as Torque Converter Shudder - and recommended a reverse flush of the transmission. I did that - and it didn't help. At least the car was due for that service anyway. I wasn't about to spring for a Tranny overhaul. I found and used an additive called Dr Tranny's Instant Shudder Fix - but that didn't do it either (seemed to help a bit at first, though). The problem had always been intermittent - and seemed to be affected by the weather (ran better when it was raining).

Finally I decided to revisit my original theory about the spark plugs. Plugs do go bad sometimes, and maybe I happened to get a defective one. So I bought another set (different brand this time) - and happened to compare a removed plug with a new one while doing the changeout. Lo and Behold! the new ones projected about 1/4" further into the cylinders (different heat range, no doubt). It seems that the counterman at the auto parts store had given me the wrong plugs on the first go-round! The car runs like a watch with the new plugs. My conclusion: One of the original plugs was misfiring - as was one of the replacements. The misfire was probably a function of cylinder pressure - which is related to engine load, throttle position - and the weather!!

Moral of the story? Don't jump to conclusions - even with "Expert" advice. Many things can make a car run rough - and intermittent problems can be a PITA to figure out.

Also, check your replacement parts against the specs before installing them. Last but not least - don't cop out and solve the problem by throwing money at it (I.E. take it to the dealer and tell them to fix it).