Notchy gearbox changing down only

[ianchubb]

Following a complete transmission failure resulting in a tow in, I've just had a new clutch and DMF fitted to my 2006 RAV4 diesel 4WD.
Since then, changing down on engine overrun from any gear is really notchy in that the clutch seems to be barely disengaging. This happens only on engine overrun, e.g. on slowing into a roundabout or before taking a turning.
A blip on the throttle after depressing the clutch and before the downshift negates the fault however.
Engaging gear from neutral is fine, as is changing up. The clutch bite point is about an inch off the floor.
The independent repairer who did the job is saying it's not a problem with his work or the new parts, so I'm heading for a bit of a disagreement with him as the repair is warranted for three months.
Anybody got any ideas as to the nature of the fault please? so I can lean on the guy with a bit more technical reasoning.
Thanks.

[RTexasF]

There is no diesel offered here for any amount of money and manual transmission is not available for North American models from 2006+. With the clutch just off the floor there is indeed something wrong....that is not the normal engagement point for any properly working clutch. Put that together with the notchy shifting and I'd say you have a good case to have the work redone.

Cheers

[pico]

We call that double-clutching and it is how I learned to drive in this (but in green) and I still do it.

However, I agree that something is simply not right. Modern transmissions are alien to me, but once upon a time we would look to the synchronizing ring for the problem.

Good luck with the repair. (Oh I wish we could get the diesel with stick here in the USA.)

[ravenuer]

Sounds like either a clutch issue(inch off the floor is too low), or a synchronizer problem in the transmission, as pico mentioned.

[ianchubb]

Thanks for the responses.

Yes I'm concerned about the early clutch bite point, I may check that out. But why is it ok changing up?

I'm sure it's clutch-related as it didn't do it at all before the repairer replaced the clutch inc cover plate and thrust bearing, and the DMF. So I'm hoping there is no synchro fault on the gearbox.

Does anyone think the (new) DMF may be suspect at all?

[Dr. Dyno]

A clutch adjustment should make it all better. The synchros are likely good. They have much less speed matching to do on upshifts than on downshifts so the upshifts are less troublesome.

Back when I had manual transmissions I stopped downshifting as a bad habit years ago. Figured brake pads are cheaper than clutches & transmissions. Downshifted only on a long downhill but never coming to a stop. I'd kick it into neutral, stop with the brakes and shift to first while stopped.

DMF?

[drzsmum]

Its probably a hydraulic clutch. I am not sure if they can be adjusted?

[JuneBug]

Originally Posted by Dr. Dyno

DMF?

Dual Mass Flywheel--it's designed to smooth out vibrations from the diesel engine, but it is complex, trouble prone, and very expensive to replace. Many owners opt to replace it with a regular solid flywheel and live with the vibrations.

[Dr. Dyno]

Originally Posted by drzsmum

Its probably a hydraulic clutch. I am not sure if they can be adjusted?

I'm pretty sure the clutch is the issue so it needs to be bled or adjusted somehow. Either that or stop downshifting. Altho I recommend that it shouldn't be necessary.

[Dr. Dyno]

Originally Posted by JuneBug

Dual Mass Flywheel--it's designed to smooth out vibrations from the diesel engine, but it is complex, trouble prone, and very expensive to replace. Many owners opt to replace it with a regular solid flywheel and live with the vibrations.

Okay, I remember them - and their issues - from the Powerstroke forum.