Lost overdrive in auto

hey guys was going for a drive last weekend loaded up camper trailer and half the car.half way along our journey I noticed on a hill the revs climb and little action.took overdrive botton off and it went fine.drove around all weekend,fine.drove 150 km home loaded just using d for drag without the overdrive button and it got us home no problem.so drive works and only have problem when in overdrive......I was thinking maybe oil change and a new filter casuse I haven't done it for about 4 yrs(50 000 km)but if it was this it would slip in all gears....yes...no.......it's probably cheaper to change to manual but I love my auto especially on the sand and the black top which is about 95%..the other 5% is on grass...I don't do mud

the car is a 4.2 diesel with auto...93 GQ.....


Just looking for pointers at what my problem may be.

Cheers

Does it accelerate hard or us it sluggish?........... Well mire sluggish than a td 42 is I mean ;):D

hey Clunk everything is as before but if I put the overdrive button on it's like the transmission is slipping...But only in overdrive....every other gear it would still pull jesus crist off the cross....

cheeers

it might be the lock up clutch (sprag clutch) in the torque converter, this would need to be engaged in overdrive to provide the 1:1 drive. Could also be an electrical/solenoid problem within the valve body.

my guess is lockup solenoid is dead

It's an electric over drive so hopefully it's a simple fix. When I did my auto I tossed up putting a manual in (I prefer manual) but the mechanic building it made me stay with the auto by saying, yes I can do a manual conversion for around the same price, but with a brand new auto, I know the history, 2nd hand manual could have all kinds of issues waiting to pop up in a months time and I'm back spending more money on it.

Check you haven't got a leak from the radiator into the ATF system. That's what killed my auto. Hope not though, good luck.

@ twisty,nah mate stopped straight away and checkedsince no oil anywhere to be found.

Al;so thanks for the tips guys will question me amate about the solenoid...he works at Nissan ford spare parts in town here so I get most things at trade rates..

so I went for a drive this morning no load and it was fine for about 10km then started slipping,same on the way back so it is when the oil warms up..Hmmmmm

I'd be dropping the fluid seeing as its been quite a while since last done.......... may or may not be the only issue though