4 speed auto changing to overdrive

[Fred Schenck]

Does any one know what causes shutter in 4 speed auto in GU Patrol when changing up to overdrive

[Sir Roofy]

Does any one know what causes shutter in 4 speed auto in GU Patrol when changing up to overdrive

might be low oil

[Bigrig]

Is it overdrive, or when the torque converter kicks in (around 85-90 klms)??

If the latter, then more than likely the seal inside the box on the TC is perished and letting oil passed it - got the same problem, but usually only when cold (when hot it expands and works).

If its shuddering all the time, definitely have a specialist look at it, as that's not good and will definitely stuff the auto box (something like the TC itself on the way out or worse) ...

Get it sussed as soon as possible mate - its damage waiting to happen, or already happening.

The other questions I'd have - have you ever changed the valve body and what oil do you use (fully synthetic??).

[Fred Schenck]

Thanks Bigrig, does most of the time, seems like when TC kicks in. Oil level is full, oil is Synthynic Nissan Brand and the Truck has doe on 60,000ks. No parts have been changed.

[bazzad]

Fred if it only happens going into 4th not the rest of of the changes in could be the valve that locks the torque convertor up. Now i have never looked at a GU transmission but i am guessing there is a lockup valve with does just that, it locks the torque convertor into direct drive when in top gear. Have a look for some loose wires or a connector that is dirty. Also look at the speed sensor wiring as this can create dramas as well.
If not as Bigrig says, get it into a workshop as it could be doing more damage.
good luck
bazzad

[Bigrig]

Bazzad is on the same path as me - that's why I asked about the valve body. There is a lockup solenoid which controls it, but generally it will be the opposite effect if the solenoid is playing up - i.e. it won't lock up on occasion or does and then releases - this could be an earthing issue, and you can put an earth straight from the box to the chassis to compensate for this and prove that's the case. Don't think that's your issue though and whilst not probable, it could be the TC itself (clutch packs stuffed), or I'm still betting on a perished oil seal. Either way, get it sussed mate as all it's doing is causing damage ...

[Fred Schenck]

Thanks Bigrig, will get it checked.

[batesy]

Hi buddy i have a 07 crd which started doin the same thing last week rang up wholesale automatics they told me it was a common problem the lining in the t/c is starting to break up, ie; new t/c needed will bugger up trans if not fixed $1760 drive in drive out, hope that helps cheers.