Transmission thud on downshift

ballmead · 02-08-2007, 06:05 PM

I have a series III AU forte and when the car downshifts there is a thud coming from the drivetrain somewhere. It feels like it's either in the auto tranny or the diff? It is especially prevelent when the car is cold and when it changes from 2nd back to 1st when giving mild acceleration? Any ideas what causes it and can it be fixed? The tranny upchanges perfectly and smoothly though.

JoesAu · 02-08-2007, 06:52 PM

take it easy while its cold, give it a service, get em to check it out bands etc, sounds like your s5 solenoid could be gone that controls 1-2nd changes

FGII-XR6 · 02-08-2007, 07:17 PM

Quote:

Originally Posted by JoesAu

take it easy while its cold, give it a service, get em to check it out bands etc, sounds like your s5 solenoid could be gone that controls 1-2nd changes

I agree S5 causes this problem

private9 · 02-08-2007, 07:53 PM

Quote:

Originally Posted by au3xr6

I agree S5 causes this problem

Exactly what mine does, has been confirmed as S5 issue.

GK · 02-08-2007, 09:43 PM

I agree with all the others!

GK

ballmead · 03-08-2007, 05:48 PM

Thanks guys. It sounds like you are onto something as the tranny seems to shift into 1st too early when cold, with a thud. I'll get it checked out.

phildee · 03-08-2007, 08:13 PM

Mine does exactly the same thing, the local auto transmission 'experts' couldn't work out what was causing it. What are the S5's worth to replace?

JC · 03-08-2007, 09:04 PM

Quote:

Originally Posted by phildee

Mine does exactly the same thing, the local auto transmission 'experts' couldn't work out what was causing it. What are the S5's worth to replace?

Not cheap. Around $180 odd for the part, plus 4 hours labour (it's a gearbox down/out job) so around $500 all up.

blackers10 · 03-08-2007, 11:22 PM

stupid gearboxes that cant stay in car GRR!!
im thinking mine might be needing a S5 even tho its only 6000km old..:S
it is shiftkitted etc internally.. but it stil doesnt feel right..

nikos · 04-08-2007, 01:35 AM

Mine bumps occasionally when going from 2nd to 3rd. Its more of a grind than a bump sound, just really quick. I guess this may be one of the solenoids?

Also when cold, the converter doesn't lock up in 4th! Does this happen to anyone else? Its usually just for 5 minutes or so, then it locks.

Cheers Nic

accurate1 · 04-08-2007, 10:16 PM

Quote:

Originally Posted by JC

Not cheap. Around $180 odd for the part, plus 4 hours labour (it's a gearbox down/out job) so around $500 all up.

The gearbox does not have to come out to change S5 maybe you're thinking about S7.

ballmead · 05-08-2007, 11:48 PM

Quote:

Originally Posted by accurate1

The gearbox does not have to come out to change S5 maybe you're thinking about S7.

Can you confirm this for me? I baulked at getting it fixed because of the cost but if the gearbox doesn't have to come out then I'll definately get it done.

GK · 06-08-2007, 01:51 PM

Quote:

Originally Posted by ballmead

Can you confirm this for me? I baulked at getting it fixed because of the cost but if the gearbox doesn't have to come out then I'll definately get it done.

I think that's right, they just drop the sump and go from there. To replace the valve body and S5 solenoid I was quoted $450 odd from Fluidrive.

If we can't confirm enough to satisfaction, just ring and ask a few auto joints.

All the best with it.

GK

accurate1 · 06-08-2007, 06:45 PM

Quote:

Originally Posted by ballmead

Can you confirm this for me? I baulked at getting it fixed because of the cost but if the gearbox doesn't have to come out then I'll definately get it done.

Only the valve body needs to come out to change S5. You need to have your problem diagnosed properly before you spend any money on changing the S5 solenoid, which more than likely has nothing to do with your problem at all. Other solenoids, not only S5, effect shift quality as well as clutch and band apply mechanisms.

bingoTE50 · 06-08-2007, 07:59 PM

I noticed mine does it a bit. I think it is more noticeable that i am driving in economy mode . Maybe a simple thing Try driving in performance(power ?) mode and see if it does anything.

ballmead · 18-09-2007, 12:03 AM

I still have this problem but I stuffed up. After more investigation, I discovered the car thuds on down changes from 3rd to 2nd gear not 2nd to first gear like I originally thought. Which solenoid controls 3 to 2 gear changes?

blackers10 · 18-09-2007, 07:29 AM

i was talking to tech trainer the other day
and he said that Economy mode is for the open road
and Power is for regular city driving..

just thought id add that in..

my trans doesnt engine brake..so they think its a busted piston inside the box :(

curtleyw · 18-09-2007, 08:33 AM

I have recently noticed that my engine braking has stopped too, I thought it was just me!

private9 · 18-09-2007, 10:34 AM

Quote:

Originally Posted by curtleyw

I have recently noticed that my engine braking has stopped too, I thought it was just me!

Nah, usually happens when you're too eager smashing it down to second and too high a speed.

curtleyw · 18-09-2007, 04:37 PM

I don't treat my box like that lol

:
Sorry what I mean is that I usually drive around town in 3rd, when going down hills the engine used to keep at 60ks and rev at about 1600rpm.
Lately gear changes have been jerky and going down a hill the car revs at around 1100rpm and speeds up. Just gotta wait for the $$$ to be saved to take it to an auto specialist.

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