Bucking AODE

[jpcavanaugh]

My daughter who is the normal driver of my 93 CV complained that the car was bucking. I have driven it and it only seems to happen when the TC is locked, never when unlocked. My first thought was an engine miss that becomes more noticeable when the TC is locked, but the engine runs smooth as a baby's butt. This bucking is very intermittent, and seems more common in 3rd gear lockup than in OD lockup. An episode will last 10-15 seconds then seems to stop. I have noticed over the past year that the TC has been reluctant to lock up in cold weather, at least until the thing gets good and warmed up.

The car has 126K on it. I have had it since about 60K, and can't remember if I have ever changed fluid or not. Anyone ever experience this symptom?

[gadget73]

Change the fluid and use Mercon V when you do. Torque converter shudder is a fairly common issue with the AODE and 4R70w, and the standard fix is either a fluid change to Mercon V or one of the Lubeguard products. If the fluid has not been changed in at least 60k miles, its due anyway.

[sly]

+1 MercV

if that doesn't sort it... the torque converter may be done and need replacing.

[jpcavanaugh]

Change the fluid and use Mercon V when you do. Torque converter shudder is a fairly common issue with the AODE and 4R70w, and the standard fix is either a fluid change to Mercon V or one of the Lubeguard products. If the fluid has not been changed in at least 60k miles, its due anyway.

I have read that the shudder is like driving over rumble strips, but this is nothing like that. Frankly, it feels like something is trying to seize or jam inside. It is not rhythmic, and feels like something is momentarily trying to lock up (and not the TC, either). I am getting the bad feeling that the tranny may be close to toasted, but I agree that it could certainly use a fluid change, and plan to try that first.

[miamibob]

Happened on my Dad's '93 GM and the dealer replaced the fluid and a "range selector sensor" and it worked! We didn't have to pay, at the time, so I was really liking it!!

[gadget73]

Try lightly touching the brake pedal when its doing this. When the brake switch is closed, the torque converter unlocks. If the shudder stops, its related to the converter. An engine misfire will also surge like this. The early 4.6 was known to have problems with the EGR channels clogging up and causing rough running at highway speeds. They also don't run well with dead plugs or wires, and if the fuel filter is old it ought to be changed.

[Nvy]

I dont mean to hijack the thread but I have a question regarding changing my fluid in my 92 MGM, I see you folks tellin this lad to switch to Merc V, is that year specific as I was browsing the forum and came across this info on a capacity post.........

One thread, for all your 4.6L 2v needs.

1992-2010 4.6L (4601cc, 281ci)

Fluid Types
Automatic transmission fluid................... MERCON (95 and up use MERCON V)
Engine Oil........................................... 10W-30 (Warmer climates) 5W-30 (Colder climates)
Brake fluid.......................................... Heavy duty DOT 3
Power Steering fluid............................. MerconV
Coolant........................................... ... 50/50 mixture of glycol-based anti-freeze and water
Differential...................................... .. SAE 80W-90 GL-5 ( add 4 oz of friction modifier unless using full synthetic oil in Trac-lok equipped vehicles.)

on the tranny fluid line it says 95 and up? So I ask can I do the Merc V in my 1992 or should I go w/ normal Mercon? My converter is doing the rumble strip vibration at 45mph or so thruout the day & I wanna see if swapping out the filter & fluid today helps or possibly (crossing fingers) eliminates this issue. Thank you for any and all info.

[sly]

There was a TSB put out about using MercV instead of Mercon in electronic transmissions due to the torque converter clutches as the MercV fluid has the needed friction modifiers that Mercon does not. I'm not sure why it says 95+ since it's essentially the same transmission from 92+ except for some wiring, solenoid changes (electrically speaking), and the 4r70w used wire ratio gears instead of the regular gears that the AODE used.

[miamibob]

When I had a similar issue in my '95 (just around 39 MPH it would not go to 40 for a few seconds) I used the Ford Limiter Slip Bottle of friction modifier. Worked like a charm and continues to this day (over 2 years ago)! Merc 5 may be overkill but certainly would not hurt. Have to drain the entire tranny including the TC to really be effective, however.

[sly]

Dr Tranny's Shudder Fixx should work well too if you just need the modifiers added...

http://www.lubegard.com/~/C-230/Dr.+Tranny+Instant+Shudder+Fixx

can be found at most auto-parts stores.

[Nvy]

Dr Tranny's Shudder Fixx should work well too if you just need the modifiers added...

http://www.lubegard.com/~/C-230/Dr.+Tranny+Instant+Shudder+Fixx

can be found at most auto-parts stores.

ty and miami as well, cheers!

[Nvy]

So I used "Lube Gard Instant Shudder Fix" stuff along w/ the Merc V Fluid & it has held up to what yall told me before hand & theres been no shudder what so ever! I used to get the rumble strip shudder couple times a day during driving around 45mph in the final gear, was almost like clock work but now as I stated, Nothing, its GREAT! So please tell me tho, is this just a temporary thing, am i just covering up a PROBLEM or is it something specifically related to fluid itself? I would love a break down of how it works and or why its doing what its doing so far as the new fluid making the problem go away. Any input as always is GREATLY appreciated my friends. Thank you in advance!

[sly]

the friction modifier does break down and needs to be replaced. If it's not replaced as it should, you get additional clutch wear (shudder). If you don't take care of it, then the clutches will wear out post haste and need a rebuild/torque converter. That was pretty much the first rebuild of my 93's transmission. When it got the PI swap, we just put in good fluid and a new, higher stall, torque converter. The transmission itself has over 100K on the rebuild. Runs like a champ.

[miamibob]

Yeah it is not a perm fix - you'll know if it has to be re-applied!! Wonder if the Merc V alone would work??

[sly]

yeah... the shudder fix is just for adding to wasted fluid as a stop-gap until you can get the fluid changed.