Mondeo Mk4.5 2.0 TDCI 140 HP - 2nd gearbox/engine issue

[Mihaita]

Hello,

    I have the following problem with my Mondeo: ONLY and ONLY in 2nd gear when driving at constant speed the car accelerates by itself for 1 or 2 seconds every 3 or 4 seconds. So it is absolutely impossible to drive it with constant speed in the second gear. The car has absolutely no problem in 1st, 3rd, 4th, 5th or 6th gear.

    If anyone has any idea what could be the cause of it it would help me a lot.

Thank you!

 

[Mihaita]

Update: There are no error codes stored.

[pragmatix]

I cant think why a manual gearbox would do this very strange, i expect it to happen in every gear.

[TomsFocus]

How low are the revs that you're trying to cruise at?  It might just be the anti stall if the revs are too low.  Could also need a PCM update (the PCM knows what gear you're in and uses a different map to suit each one) there's no physical gearbox component that could cause this.

[Mihaita]

It is not RPM dependent. It happens from idle rpm to 4000 rmp... Only in 2nd gear.

One other thing I tried: running whit let's say 40 km/h , put it in neutral  and press the acceleration pedal to a steady ~2000rpm -----> the rpm shows increase of revs every 4-5 seconds. So it is reproducing also in this scenario.

Could a bad abs speed sensor cause this?

Thx!

 

[Mihaita]

I thought it would be a simple cause for this but it turns out it is not. So full story:

Last winter i sometimes i could hear the DMF when starting from still. So I decided last month to change the DMF + clutch. Went to a local shop and they replaced them.

After this all was good until i started to fill knocking in the clutch pedal and oil dripping under the gearbox. Took it back to the shop and recovered it after 3 days.

They said they had to REPLACE THE GEARBOX!!!

So they replaced the gearbox on their expense (which was nice...) but I don't know what really led to this fault.

My suspicion is that this "new" (actually a used) gearbox has a different ratio in 2nd gear but they assured me they took the "new"  gearbox by code.

Today I took the car to a Ford dealership. They could not find anything wrong that could cause this fault (accelerating by itself in 2nd gear every 3 seconds).

But we did manage to read the "new" gear box part code: AG9R-7002-KA 63

The Ford dealership said this is not the proper part for my car. It should be: AG9R-7002-MCC

For AG9R-7002-MCC i know the ratio in 2nd gear is: 0.94

 

Does anybody know what ratio has AG9R-7002-KA 63 in 2nd gear?

 

 

 

 

 

 

 

[Mihaita]

Update:

Put the old  repaired AG9R-7002-MCC  back. All good now.

If anyone is interested the mechanic said the AG9R-7002-KA  had one additional tooth in the 2nd gear compared to AG9R-7002-MCC.

[FatHead1979]

On 5/13/2019 at 3:49 PM, Mihaita said:

Update:

Put the old  repaired AG9R-7002-MCC  back. All good now.

If anyone is interested the mechanic said the AG9R-7002-KA  had one additional tooth in the 2nd gear compared to AG9R-7002-MCC.

Wow, it just goes to show how the really small details can make all the difference.  Fair play on posting back as your experience may help someone else some day. 👍