The car will seem to engage reverse hard and if it does then transmission fault will display and the vehicle will only drive in limp mode ( no power and acceleration)
it does not always do this, there can be a couple of days at a time when everything is fine, and then the problem resurfaces.
it only happens when selecting reverse.
When the problem has not occurred the car shifts perfectly and sport mode works fine.
this has been going on for about a year now with no change. There is no deterioration in the way the car shifts ( unless the fault light shows up in reverse as described) so it’s
hard for me to see this as a transmission problem
All fluids are new and full and the car just turned over 100k

 

The TCM will have DTCs logged.
It will help with diagnosis if you can retrieve the codes and post them.

 

Did you flush the transmission? What ATF you used ?

 

Transmission was flushed and the fluid changed twice. I’ll have to check what we used.
it usually does not throw up a code when this happens. Once in a while it will do so. I will see if I have a record of the code

 

Here is a snapshot of the code reader

 

I also took out the dual linear switch and cleaned all the contacts but it made no difference to the issue

 

I believe this happen because of the flushing looks like the ATF very thin drain 1 quart then added 1 Lucas transmission fix ATF it has high viscosity will prevent slipping. It might be electrical but I don't think it's the gear selector , flushing is bad for old cars

 

P0705
Dual Linear Switch fault

 

You may have poor contact in the connector to the switch or in the connector to the TCM (the pins related to the linear switch).
The linear switch has electronics inside so the problem could also be there. Possibly deteriorated solders causing intermittent loss of contact; or an electronic component on the way out.

 

Yes...to me, it sounds more like an electrical issue than an actual problem
with the transmission. If it was problems with the transmission, there would
be issue in drive as well.

 

I think is is an electrical issue too, it is also intermittent. It happens almost always on engaging reverse on cold start up, but it can also happen after the car is warm as well.

every time it happens it feels like it shifts hard into reverse, as if the transmission is getting the wrong signal somehow. The car never shifts hard at any other time and never in forward gears.
then there are other times when I put it in reverse and is goes in gently and the fault does not occur.

 

It seems there are two types of limp modes, mechanical and electronic
Electronic would keep the vehicle in the selected gear until switched off and after that it would operate in second and reverse only.
that is definitely not what is happening in my case.
Mechanical would shift into third gear only and remain there. This is also not what my car is doing.
With my car the message “ transmission fault” will show on the dash ( most times without the engine light coming on) and the car will shift normally but with limited power ( and sport mode will not work)
this appears to be what should happen with P0705 codec due to the dual linear switch signal malfunction according to the bulletin

once I switch off the engine and wait a few seconds it will run perfectly normally again.
sometimes it will still be in limp mode when I turn it back on and I will have to turn it off and restart to get it back to normal.


does that make sense to anyone?