I have a 96 Grand Marquis I bought over 2 years and nearly 25,000 miles ago. It has 110,000 miles now and i am experiencing a slight shake in the car that I believed was engine related. A friend owns a slightly newer one and says he has the same problem and mechanic told him it was the cracked plastic intake manifold. I now believe it is likely the transmission shuddering. It happens mostly under acceleration and under a bit of a load like climbing a hill.
96 Grand Marquis LS transmission shudder
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when is the last time the plugs/wires have been changed?
Originally Posted By: Black_Thunder
when is the last time the plugs/wires have been changed?
+1
when is the last time the plugs/wires have been changed?
+1
I third the plugs and wires.
Do you still have the plastic intake manifold, or has it been replaced with one that has an aluminum crossover?
Also, your torque converter has a drain plug. If you haven't replaced your ATF, drain the converter and drop the pan. Replace the filter and refill with Mercon V.
Do you still have the plastic intake manifold, or has it been replaced with one that has an aluminum crossover?
Also, your torque converter has a drain plug. If you haven't replaced your ATF, drain the converter and drop the pan. Replace the filter and refill with Mercon V.
Originally Posted By: Falcon_LS
I third the plugs and wires.
Do you still have the plastic intake manifold, or has it been replaced with one that has an aluminum crossover?
Also, your torque converter has a drain plug. If you haven't replaced your ATF, drain the converter and drop the pan. Replace the filter and refill with Mercon V.
The plugs and wires might help. I actually had a torque converter shudder when I replaced the Dex/Merc with Mercon V. I added a bottle of LubeGuard Red and all is now well. We'll see how long that fix lasts.
I third the plugs and wires.
Do you still have the plastic intake manifold, or has it been replaced with one that has an aluminum crossover?
Also, your torque converter has a drain plug. If you haven't replaced your ATF, drain the converter and drop the pan. Replace the filter and refill with Mercon V.
The plugs and wires might help. I actually had a torque converter shudder when I replaced the Dex/Merc with Mercon V. I added a bottle of LubeGuard Red and all is now well. We'll see how long that fix lasts.
Have not changed plugs or wires since I have owned it. Wires look new so I may try plugs first as they are pretty easy on this car. anyone know what transmission this has? I have read about some Ford rear wheel drive tranny's having issues. Do not have any history on the car but it looks like new so not sure about any fluid changes other than oil.
Try this the next time it happens:
Holding your right foot steady on the gas, GENTLY tap the brake pedal just enough to make the brake lights come on. If the shudder stops immediately, you have the infamous torque converter clutch shudder and changing the fluid will fix it.
If the shudder continues, then you may have some engine issue: clogged EGR passages (common), bad DPFE, spark plugs, etc.
Holding your right foot steady on the gas, GENTLY tap the brake pedal just enough to make the brake lights come on. If the shudder stops immediately, you have the infamous torque converter clutch shudder and changing the fluid will fix it.
If the shudder continues, then you may have some engine issue: clogged EGR passages (common), bad DPFE, spark plugs, etc.
if you think its the atf have it checked out and make sure you have the correct fluid in there it should be mercon 5 to prevent shudder
These trans are prone to torque converter shutter. I have known several people with this same problem. Cure: Have the fluid in the trans and converter changed. There is a drain plug on the torque converter, so be sure that fluid is drained.
Did not check yet to see if it has plastic intake manifold or aluminum. Thanks for all the advice.
How would I be able to check if the car has the correct ATF? It was in the car when I purchased it and no records of what was used. Have driven about 25,000 miles though and just starting to get the minimal shutter on acceleration under light or heavy loads.
Do the test that RF overlord posted. When you step on the brake, the torque converter unlocks. Ergo, if it keeps shuddering its something else causing it. On the other hand, if it stops, its the infamous torque converter shudder which just means that the fluid is due to be changed.
There isnt anyway to tell what fluid is in it.
Honestly, with that many miles, and no service history, I would go ahead and change the fluid. Drop the pan, change the filter and drain the torque converter.
While you are at it, change the spark plugs and wires and make sure it has the aluminium crossover intake manifold.
I dont think it locks the torque converter until 30mph or so anyway; Its been awhile since Ive had factory programming on my car, but that sounds right. If it occurs below that then it isnt the trans.
There isnt anyway to tell what fluid is in it.
Honestly, with that many miles, and no service history, I would go ahead and change the fluid. Drop the pan, change the filter and drain the torque converter.
While you are at it, change the spark plugs and wires and make sure it has the aluminium crossover intake manifold.
I dont think it locks the torque converter until 30mph or so anyway; Its been awhile since Ive had factory programming on my car, but that sounds right. If it occurs below that then it isnt the trans.
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the transmission it has will be the 4R70W.
I have a 97 t-bird with the same engine and transmission, i've only used regular mercon and i don't have any shudder issues.
i know ppl have simply drained out the mercon and put in mercon V but they aren't supposed to be mixed at all so i guess a flush wouldn't be a bad idea.
also might wanna try the Dr. Tranny additive.
but if the shudder is an engine issues, it will mostly likely be the wires not the plugs but its not a bad idea to change both, and i would only use motorcraft plugs and motorcraft wires.
I have a 97 t-bird with the same engine and transmission, i've only used regular mercon and i don't have any shudder issues.
i know ppl have simply drained out the mercon and put in mercon V but they aren't supposed to be mixed at all so i guess a flush wouldn't be a bad idea.
also might wanna try the Dr. Tranny additive.
but if the shudder is an engine issues, it will mostly likely be the wires not the plugs but its not a bad idea to change both, and i would only use motorcraft plugs and motorcraft wires.
No issue mixing Mercon oand Mercon V.
There was some suspicion, at least on behalf of the people I talked to that had some version of inside info, that the reason behind not mixing them was so that Ford could exhaust their own supply of Mercon from inventory. When the supply dwindled, then suddenly it was A-Ok to mix.
The ink wasnt even dry on that spec when I used Merc V in a Mazda and Toyota (not either of the ones I have now) and drove them for years. I'm sure some of our resident experts can give reasons why its not good to mx them, but anecdotally I did it for years over several hundred thousand combined miles with no issue.
Back on topic.... my mother-in-law's Marquis was experiencing simmilar symptoms (shuddering) usually at lower speeds, or under light throttle, especially on slight grades. We went all over that transmission to no avail. Computer was throwing no codes either. Turned out not to be transmission or fluid related at all, it was the throttle position sensor.
The ink wasnt even dry on that spec when I used Merc V in a Mazda and Toyota (not either of the ones I have now) and drove them for years. I'm sure some of our resident experts can give reasons why its not good to mx them, but anecdotally I did it for years over several hundred thousand combined miles with no issue.
Back on topic.... my mother-in-law's Marquis was experiencing simmilar symptoms (shuddering) usually at lower speeds, or under light throttle, especially on slight grades. We went all over that transmission to no avail. Computer was throwing no codes either. Turned out not to be transmission or fluid related at all, it was the throttle position sensor.
I 2nd Falcon's recommendation..
I used to own a '96 Crown Vic for a number of years.
That model year had a drain in the torque converter.
Do a pan drop and drain the converter, and you can drain about 12-13 quarts out of the 14 quart capacity.
Refill with Mercon V.
I remember my 4.6 running better after Seafoaming it and cleaning the TB and only running Motorcraft Plat plugs. It didn't like Bosch plugs for some reason. Change the plugs after de-carbonizing the combustion chambers with the Seafoam.
The shudder may be from the previous owner having the trans serviced with the wrong ATF, or b/c it needs a tune up.
Good luck.
I used to own a '96 Crown Vic for a number of years.
That model year had a drain in the torque converter.
Do a pan drop and drain the converter, and you can drain about 12-13 quarts out of the 14 quart capacity.
Refill with Mercon V.
I remember my 4.6 running better after Seafoaming it and cleaning the TB and only running Motorcraft Plat plugs. It didn't like Bosch plugs for some reason. Change the plugs after de-carbonizing the combustion chambers with the Seafoam.
The shudder may be from the previous owner having the trans serviced with the wrong ATF, or b/c it needs a tune up.
Good luck.
I owned a 99 Crown Vic for a few years. Easiest way to dump the trans fluid it take the top rubber trans coolant line off. Re-direct to a bucket that you can place under the car. Start the car and it will pump it out. Soon as it starts sputtering shut the car off.
There will still be a sh*tload of fluid in the valve body so when the pan comes off beware.
If you don't pump it out man o man is there alot of fluid behind that pan!!!
Go over to crownvic.net forum as there is extensive talk about the 4r70. Doing the "J-mod" is very very popular over there. Its drilling out the valve body plate to increase flow to the valve body so it shifts very firm. Extends the life of the trans. Very popular.
Oh and put Mercon V only. It will take 14 quarts with a tc dump.
There will still be a sh*tload of fluid in the valve body so when the pan comes off beware.
If you don't pump it out man o man is there alot of fluid behind that pan!!!
Go over to crownvic.net forum as there is extensive talk about the 4r70. Doing the "J-mod" is very very popular over there. Its drilling out the valve body plate to increase flow to the valve body so it shifts very firm. Extends the life of the trans. Very popular.
Oh and put Mercon V only. It will take 14 quarts with a tc dump.
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