GT Nate

Had my transmission flushed at 63K... Took them a bit to get the coolant lines undone as Chicago weather had rusted them.

They did the flush, and twice now when I stop at a light or stop & go traffic when I press the gas pedal there will be a half second where it's like I'm in neutral, then BOOM it kicks in and off I go (not a squealing burnout, just wait then it hits)
I don't think it's a tranny issue (thought perhaps it was grit in a solenoid getting worked out as the flush involved using a cleaner first, then they added fluid)..

I'm more suspecting it's the throttle body. I did the key on calibrate thing 3 times and that seems to help, but considering the car is 8 years old I don't doubt maybe that throttle body motor is so heat soaked from the years of use that it's not working as good as a new one. EBay has a Ford OEM TB for $196 I'm probably going to buy.

Just wonder what you guys think, how your tranny flushes went.

Thanks Amigos!

Nate

08'MustangDude

How did they flush it? IF they let the pump do the work, it should be fine. Was
the filter changed as well? With 100% fresh fluid, and the old filter, the thicker
fluid will not pass through loaded filter as quickly as the old thinner fluid did. This is
why a simple fluid change works fine, because you only get what's in the pan,
and have 6-7 quarts still in the trans, mixed with 3+ quarts of fresh fluid.

Also, they should not have ran anything but fluid though the transmission, just
cycled out fluid in the same direction as the pump cycles it through If the filter
was still in it when they ran solvent through it, that that was useless, as the
cleaner will dissolve and push some of the caught material in the filter, through
the trans, unless they did it backwards. However, if they did it backwards, all
the gunk wend down on top of the filter, and would not clean out. So, then going
forward again, all that gunk would then pass through the system again and can get
stuck in the solenoid area and clutch packs.

You mentioned grit maybe, and there should be NONE if done correctly.

Will it start better in 2nd gear? You can put the selector in 2, and it will start
out in 2. See if it hesitates and bangs into gear as you shift forward from there.
Line pressure will be a little lower when starting out in 2.

After a flush, shift adaptations need reset so it can relearn the new pressure values,
clutch engage pressures and indexes. It may stop doing that after a while if it is
learning now.

If you're gonna buy another TB for $196, you may as well look for a bored one, and
spend another $54.00 and get one, BBK, or see if any other ones are available.
If it did not do it before the flush, then it could not be the throttle body, because there
wasn't an issue beforehand. You would have had the hesitation before taking it in
for a flush. Also, there is a difference between a slight dead-spot or bog down area
in the TB -vs- the trans clutch engagement.

GT Nate

it's done it before the flush.. once in a parking lot...hasn't done it since 2nd time of the flush though. I agree, I think it's relearning values.. Seems to be fine now.

They flushed it with a specific flush machine. Through the cooler lines. A guy also sat in the car and cycled through the gears to work the system as the flush was ongoing. First a detergent cleans out the crud, then a flush with new Mercon V. So this method got it all out of the torque converter as well. Took them about 2 hours as the cooler lines didn't want to come undone.

Since then, it's been mostly fine...

Thanks for the insight!

Derf00

There's a relearn procedure for the transmission if you want to make it learn faster. Chances are though this is mute since you've been driving it for a bit. This is normally done for a fresh tranny install or after you've had the battery unplugged for x number of minutes to clear the PCM memory of all codes and learned/adapted behavior.

Anyways: https://etesupport.zendesk.com/hc/en...-Transmission-
TEST DRIVE CYCLE PROCEDURE

The transmission drive cycle test must be followed exactly.

Transmission failure must occur four times consecutively for shift error DTC code to be set, and five times consecutively for continuous torque converter clutch code
set.

Perform a KAM (Keep Alive Memory) Reset. A scan tool will be required to perform this procedure.

1. Record and then erase Quick Test codes.
2. Warm engine to normal operating temperature.
3. Make sure transmission fluid level is correct.
4. With transmission in D position, moderately accelerate from stop to 50 mph (80 km/h). This allows the transmission to shift into 5th gear. Hold speed and throttle open and steady for a minimum of 15 seconds.
5. With the transmission in 5th gear and maintaining a steady speed and throttle opening, lightly apply and release brake to operate brake lights. Then hold speed and throttle steady for a minimum of 5 seconds.
6. Brake to a stop and remain stopped for a minimum of 20 seconds.
7. Repeat steps 4 through 6 at least 5 times.
8. Carry out Quick Test and record continuous DTCs.
9. Install vehicle back on a hoist and reconfirm the transmission fluid level.
10. Verify that there are no leaks present.

It is now safe to release the vehicle.

Derf00

As for the issues you're talking about, is the engine reving up while it's sitting there then the transmission engages (delayed engagement) or is the RPM sitting there for a second then revs up (engine throttle lag)?

Delayed engagement can be a bad/worn valve body or failing transmission solenoids. I just redid the valve body shift kit and sonnax upgrades that my old valve body had. My old valve body went with my old tranny when I shattered the input shaft and ended up going with a remaned transmission. The 'new' remaned valve body that came with the remaned transmission didn't have any mods made to it from what i could tell both by driving it for the last year and when I tore it down t his last weekend.

Feels sooo much better now and like it was before it was before the input shaft shattered.

And by worn valve body I mean springs and or bores that are weak/worn out.

GT Nate

No it didn't rev, push gas pedal enough to gently take off, no rise in RPM's...then boom it'd take off with a lurch....but not at breakneck speed...
So it can't be the tranny if the engine RPM's didn't rise. I really think the throttle body was either out of calibration, or the motor which opens and closes the butterfly valves just is old... nothing lasts forever and with no previous knowledge of what the previous owner(s) did to it I can't say for sure it's not just worn out.
But last few days it's been running fine.. I cleaned the MAF and did the relearn procedure for the throttle 3 times and that seems to have helped.

I'm keeping a close eye on it, if it does it again I'll replace the throttle valve motor....it's an easy swap.