just wondering why my 4sp changes with a thump and slips occasionally, but it only when its warmed up after 15 or so minutes. cold it changes really well so I'm thinking maybe its a dodgy sensor? or is the auto stuffed?

cheers

This is exactly the same problem i had a week ago. Mine occasionally kicks down with a big thump at the end. And only does it when the engine is hot. I got mine fixed by replacing Solenoid S1, S2, and S3. Cost me $520.

This is exactly the same problem i had a week ago. Mine occasionally kicks down with a big thump at the end. And only does it when the engine is hot. I got mine fixed by replacing Solenoid S1, S2, and S3. Cost me $520.

Thanks for that, I have the same problem too, now I know what needs to be fixed, and how much dosh now!

Wolfpac

Could be any soleniod....be is S1, S2, S3.....S5 etc

Mine does the same damn thing, been told its having 'leak down' issues where the solenoids arent doing there thing when the trans fluid gets hot, or i have a crack in the valve body. Considering mine has done 230 000klms, and has copped a hiding, im assuming clutches and bands and all that good s**t will be f**k as well

time for a 5speed.

yea ours duzt it to...but only when driving hard...so we'll live wif it

S1 is the shift soleniod and S5 is the damper soleniod, i had to replace S1 as it went into limp mode. the soleniods are so simple to replace just have to replace the fluid, filter and wise to do the sump gasket also.

Explains why it's so expensive to replace the solenoids, then... And I just had the auto serviced (full flush) not that long ago either.

Wolfpac

i got a quote after i repaired the trans from a place in hallam/melbourne. it was $180 to replace S1 (original Bosch) and another $90 for the service. they have to drain the fluid and remove the filter anyways!!! the only extra thing is to flush the lines.

I used to think the same way you do unitl I read the workshop manual for EL Falcons. To summarise:

S1 and S2 - determines static gear changes.
S3 - controls presssure on clutch for shift quality.
S4 - controls pressure on front band for shift quality.
S5 - is a variable pressure solenoid that works with S3 and S4 and this solenoid activates depending on speed, rev, gear posisiton etc.
S7 - lockup solenoid.

- if takes a long time to change gears and feels like slipping, then suspect your S1 and S2.
- if upshifting from 1-2 is harsh then suspect your S5. Problems with S5 is exhibited by harsh upshifting
- if downshifting is harsh but smooth on upshifiting then suspect your S3. This is exhibited by a big thump at the end of kickdown or downshifts.

Using this logic is far better than using computers to diagnose solenoid problems. Most of the time solenoid have mechanical problem rathen than electrical.

If anyone is interested of knowing more. I can post the complete info of how these solenoid works together in conjuction with S3,S4,S5 to select gear and shift quality.

Wow! Thanks for that John_Jay, that's great!

Wolfpac

cheers jon jay