Transmission overdrive issue

[slevreault]

I have a 2005 Mustang GT Convertible, 4.6 V8, 106K miles, automatic. Only modifications cold air intake.
when driving at 40-45MPH the overdrive seems to jump in & out. 50 and over nice and smooth, or shutting off overdrive everything fine shifting. Anyone else have this? Is there a sensor or something that would cause this or is this a big transmission issue? Thanks for any help. Steve

 

[07 Boss]

Well the transmission is electronically controlled so I would think you could make some tuning adjustments. Not exactly sure what tables you would need to adjust but probably something to do with pedal position and engine load is what it probably uses to select what gear you should be in.

Has it always done this or is it something new?

 

[slevreault]

This is something new, always shifted fine, just started to jump in and out of overdrive, fine at higher speeds.

Where would I go that could do tuner adjustments? Or do I need to purchase a tuner?? $$$$?

 

[07 Boss]

This is something new, always shifted fine, just started to jump in and out of overdrive, fine at higher speeds.

Where would I go that could do tuner adjustments? Or do I need to purchase a tuner?? $$$$?

Well since it is new I would rule out tuning. I mean you could probably get it to shift better but it would just be a band aid masking the real issue. You might have to take it in as it could be anything from a bad MAF signal to the transmission control module.

 

[Laga]

Overdrive has a band that can adjusted in the 5r55s. Since you have 100K miles on it. It worth adjusting it before more expensive alternatives.

 

[slevreault]

Thank you both!

 

[Whpony96]

Also you can perform the relearn procedure on the trans. This can be initialized with a Ford IDS tool or the ForScan software.

 

[Monkeyporn]

I have a 2005 Mustang GT Convertible, 4.6 V8, 106K miles, automatic. Only modifications cold air intake.
when driving at 40-45MPH the overdrive seems to jump in & out. 50 and over nice and smooth, or shutting off overdrive everything fine shifting. Anyone else have this? Is there a sensor or something that would cause this or is this a big transmission issue? Thanks for any help. Steve

Steve O/D doesn't engage until your speed reaches between 50 to 55 mph.

 

[slevreault]

Yes, that's what I thought, but when you back off to slow down to 45 that's when it starts jumping in and out. Unfortunately most of my driving in my area of FL, is 45-50MPH.

 

[Derf08]

If a band adjustment doesn't work, it could be servo bore wear on the overdrive band. Symptoms/Solutions. Start simple and keep going until the problems gets fixed. Worst case, install a new servo from this site. Alternative is a Trans rebuild and case repair.

https://www.fordservoboretransmissionfixsolution.com/symptoms--solution.html

https://www.fordservoboretransmissionfixsolution.com/how-the-fix-works.html

 

[slevreault]

Thank you

 

[Derf08]

One other piece of advice. Check the fluid level first.

It's a bit of a pain since the car needs to be level and you have to have access to the underside of the car's transmission pan. These cars do not like low fluid level and they will have shift issues from low fluid. .

 

[Pentalab]

Steve O/D doesn't engage until your speed reaches between 50 to 55 mph.

On my 2010 GT auto, OD would engage at 30 mph.... and result in 1000 rpm on the tach. After VMP retuned it (LT's, 94 octane, FRPP twin 62mm TB, Roush M90 blower etc, he also tweaked the speed at which OD engaged, which is now 40 mph. Same 5R55S auto tranny.