Sigma 3.0 Auto - Overdrive Problem Options

[Pork Scratching]

Hello, I've just bought a 1994 Sigma 3.0 V6 Auto Estate. It's called a Sigma in the UK, not sure in other markets (Magna? Diamante?). It's a UK registered, Australian built car anyway. They are very rare over here - maybe only a couple of hundred were ever registered.

I've read through several posts on here about overdrive problems, but mine is somewhat different. In normal gentle driving with OD on, I have all 4 gears selecting correctly. If I travel at 60mph and switch OD off it changes down to 3rd correctly, and if it turn it back on it changes back up to 4th (overdrive). All good so far! The problem I'm having though is that on hard acceleration it "misses" 4th (overdrive). At about 60 it tries to change up, but then just revs as if in neutral (similar to what I understand would happen if the OD end clutch pack had gone), however, if I then back off, it finds 4th (overdrive) after a couple of seconds. If I just gently accelerate, it all seems to work fine.

From the above behaviour, I assume that all the electrics are working fine, but that some mechanical part has become sluggish/sticky can this happen? Do I need a new OD clutch? Could it be a sticky solenoid? Does the Auto box fluid also lubricate the overdrive? Would a fluid change help matters?

Any help you can give me would be great.

Thank In advance.

Rob

[chain rattle]

you just have to repair the end clutch

the auto stays in the car

its called the end clutch its at the end of the gearbox a plate held on by 10 mm bolts

the plate to the left of the gearbox in my avatar

you can buy a repair kit for it from an automatic spare parts place if you want to DIY

the friction and drive disks are worn out
the drive plates have to soak in auto oil for two hours before fitting

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[KiT TeUnG 2549]

Yes , replacing the Over-Run clutch set will correct the problem. In the Galant section sumone had asked about info on it and i put of actual pictures of on the car replacment of the clutches. The transmission i was servicing the Over-Run Clutches on was with an F4A23 , but the F4A33 transmission is the same in outer cover removal and replacment of the end clutches , and always remember the snap ring after replacing them or the job will fail , and its a good idea to service yur fluid and filter at the same time.

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[Pork Scratching]

I'm going to try changing the transmission fluid and filter first as it could probably do with it anyway. If that makes no difference, JPAT seem to have the end clutch parts in the UK - you say mine is the F4A33 transmission, should that be the same kit as for the F4A32-1 as the F4A33 isn't listed? I know I'll have to do the fluid again to do the end clutch, but that will help flush the torque converter anyway.

Rob

[Pork Scratching]

I've attached a picture I got from the local Mitubishi Dealer can someone give me the part numbers I'll need for the repair. It looks like I'll need:
5 * 27463
5 * 27405

But which other parts do I need - its hard top work out which parts are the necessary seals.

Attached File(s)

 endclutchparts.jpg ( 216.16K ) Number of downloads: 9

 

[KiT TeUnG 2549]

That picture yu showed is of internal clutch sets , the one way is because the drum band is pictured. The Over-Run clutches yu will be replacing does not have a clutch drum band surrounding the assembly. The onlee seals that are there are on the Over Run clutch rear housing plate. The diagrahm yu have showed is not of the OVER RUN clutch set.

The differance between the F4A31 , F4A32 m F4A33 , is the arrangement of clutches , an F4A31 and F4A32 have less 1st gear clutches than the F4A33 , 2nd gear up are the same , but the F4A33 has , depending build code , has 1-2 more in the Over Run clutch pack than the F4A31 and F4A32 , they are the same size tho. a set of clutches for the Over Run section for an F4A32 should have all the clutches yu need tho for the F4A33

[Pork Scratching]

Thanks for the information - I'll get back to the dealership for a new diagram.

[KiT TeUnG 2549]

Also there should be other places that sale transmission parts to which yu can get the needed friction clutches at a way cheaper cost and better assist yu.