OverDrive Gear -Weird- Problem. 91 T-bird...help/advice needed

[Donald91tbird]

Model: 1991 Ford T-bird LX. 3.8l,auto. MILEAGE: 151,000

Hey, Ive had my car for about 8months now. Ever since I had it I thought my transmission was skipping and the brakes were bad. Its an unusual problem that would probably take experience to know this particular situation...

Everytime I drive my car in the Overdrive gear... It skipps roughly at about 40-45. I don't have an RPM in the gauge on this model car. But I've been looking at it everytime and that is the exact interval! So anyway, It does that when accelerating but get this ...when it down shifts either coasting or braking it sorts surges. I find trouble describing it or finding the word . However, after so many times I can tell you I can feel it in the rear (like a pulling feel). I don't know what it is, I dont exactly think its the Overdrive kicking in at 40-45... that cant be it? Its hard to trust mechanics here nowadays. You have to really know what your dealing with or else they'll eat you ALIVE!!!

haha. Sad but true.

In conclusion I would also add that in the NORMAL Drive gear (D) ... Everything seems alot smoother. Transmission isn't noticibly rough or missing and no surging when braking!

I know some of you are gonna say well just drive it in regular Drive gear!! But I read that OD keeps engine in lower rpm's and eventually reduces engine wear. Another thing, gas is about $2.14 right now. But my main concern is, that if I keep driving it like that will it worsen? will this problem spread and eventually damage something? I hope to find out.

I'll just drive it regular till someone comments If any additional information is needed... feel free to ask.

Thanks.

[cougarman]

The "skip" your describing at 40-45 on accelll,, does it feel like driving over a washboard type road, that is more of a shudder/vibration ?
If so then the cause is due to torque convertor clutches shuddering while locking up. This is ussually caused by fluid breakdown. To correct a torque shudder , flush the transmission, replace the trans screen, and fill with
the correct Ford recommended fluid as per owner maint manual. Also with the new fluid add an auto trans shudder additive like Wynn's auto trans treatment. The shudder ussually disappears after about 150 miles.
Give it time to work in. Sometime it won't correct the problem, then the torque has to be replaced. It may be a good idea to get a tranny shop rep or Ford dealer foreman to go for a road test with you to feel the concern if your not sure. Many times they will road test with you at no charge.

[Donald91tbird]

yeah It feels like a shudder/vibration but at the same time sorta revs up in that range (40-45). I'll take your advice though and flush the fluid. I might take it to a transmission shop also.

[compewterman]

Short of having the trans drained and flushed completly TC included you can get a small red plastic tube of conditioner called transmedic or DrTrans approx 6 oz pour it down the trans check tube and within 5 miles that should go away. Seems Ford knew of this and there were a lot of t-birds that came of the line that a trans additive was added to the fluid to keep this from happening. IF you cannot find this then take it to a reputable place in your area that does complete trans flushing including the Torque Converter

[steviewonder_13]

can this also happen when idling in drive (stoplight) or when accelerating from a stop, because i have had a similar problem where it feels like the rear end is running over 'bumps' although the car isn't moving

'97 V8

sry about the thread theft, lol