tranny problem, really freaked out

[nivek111070]

if i get a rolling start and shift out of first at almost redline about 30% of the time I can't get it into second, will grind like crazy...

[mwjcyber]

When it comes to an expensive engine or transmission failure, any non-OE connected components are an excuse to deny coverage waiting to happen. Have fun spending lots of money on an attorney to challenge a dealerships decision.

Me personally, if I had aftermarket bushings on my transmission experiencing these issues, they'd be off in a second.

[stugray]

Originally Posted by Cridland

It's only happened once or twice, think I should wait? And all I have is a trd quick shift kit. I installed it though does that make a difference?

Originally Posted by Turkish

It could, even if it isn't related to the issue, they may finger point to deny warranty.

Originally Posted by mwjcyber

When it comes to an expensive engine or transmission failure, any non-OE connected components are an excuse to deny coverage waiting to happen. Have fun spending lots of money on an attorney to challenge a dealerships decision.

Me personally, if I had aftermarket bushings on my transmission experiencing these issues, they'd be off in a second.

I would agree with the above EXCEPT for the TRD products.
They cannot be denied since they are provided by the manufacturer.
And Yes - even for a BRZ.

[Cridland]

Originally Posted by stugray

I would agree with the above EXCEPT for the TRD products.
They cannot be denied since they are provided by the manufacturer.
And Yes - even for a BRZ.

Originally Posted by stugray

I would agree with the above EXCEPT for the TRD products.
They cannot be denied since they are provided by the manufacturer.
And Yes - even for a BRZ.

What about TRD parts self installed? And a reverse lock out?

[stugray]

Originally Posted by Cridland

What about TRD parts self installed? And a reverse lock out?

They cannot deny you any warranty work just because you do the work yourself.
You can even do all of your own periodic maintenance as long as you keep accurate records and receipts to prove you did it.

With that said, I still let the dealer do my oil changes just so it goes in their record.

[Cridland]

Originally Posted by stugray

They cannot deny you any warranty work just because you do the work yourself.
You can even do all of your own periodic maintenance as long as you keep accurate records and receipts to prove you did it.

With that said, I still let the dealer do my oil changes just so it goes in their record.

Cool thank you!

[litemup]

Originally Posted by Cridland

Going 45-50km downshifting from third to second, rev matching with clutch in and I cant get it into second until I come to a dead stop

With the clutch in, rev matching does nothing. Go back and read @wheelhaus post on understanding how the transmission works. Double-clutching is THE KEY.

From third to second, here are the steps:

1. disengage clutch.
2. third to neutral.
3. engage clutch.
4. rev engine significantly over the speed at which it would rotate if you actually were driving in second gear. This is critical. You are now spooling up the input shaft.
5. while revving the engine, disengage the clutch.
6. quickly, before the input shaft has a chance to spool down, gently nudge the gearshift lever so it's resting against the second gear syncro.
7. wait for it ... ahhhh! enjoy the buttery plunk of your transmission literally falling into second gear.

If it didn't work then you either didn't rev high enough in step-4, didn't disengage quickly enough in step-5, or weren't quick enough in step-6.

You will know you got it right when second gear just flops into place.

If you practice this with all downshifts, and are gentle about waiting for the input shaft to spool down during upshifts, your transmission will love you long time.

[wheelhaus]

Originally Posted by Cridland

Going 45-50km downshifting from third to second, rev matching with clutch in and I cant get it into second until I come to a dead stop

The wall you're feeling may simply be the synchro trying to speed up the input shaft, but without sufficient friction to make it happen, so you never get past the bump. This is the synchro doing its job, by preventing engagement when the speeds aren't matched. After a moment the shaft will want to spin down further, making engagement even more difficult on the synchro.

Either practice the double clutch technique, or simply use a little more force on the first attempt to give the synchro the force and friction it needs to spin up the input shaft.

Rev matching is for the engine to re-engage the clutch at match speed, it does nothing for the synchros (because they're on the other side of the clutch) unless you're double clutching a downshift.

[stugray]

Originally Posted by wheelhaus

Rev matching is for the engine to re-engage the clutch at match speed, it does nothing for the synchros (because they're on the other side of the clutch) unless you're double clutching a downshift.

I am trying to visualize what you are saying there and it makes sense.
On an upshift -
When you press the pedal and release the clutch (engage the throwout bearing), you decouple the engine from the trans input shaft.
Then when you pull the trans out of gear the output shaft and the input shaft are now free to spin independently.
The output shaft will keep spinning at the previous rate because it is connected to the rear wheels.
However the input shaft is not hooked to the engine, or the output shaft.
It is spinning under it's own momentum, and slowing (quite rapidly BTW).

Now you attempt to press into the next gear.
The input shaft needs to be spinning slower now to engage with the next gear up and the synchros will provide the friction to match the speed of the input shaft to the output shaft (now through a different gear ratio).
If you shift slowly then the input shaft may have slowed too far and the synchros have to speed UP the input shaft.
If you shifted really quickly, then the synchos will have to slow down the input shaft.

IF you wait exactly the right amount of time, the two shafts will be spinning at the right rate to engage with NO PRESSURE on the synchros.

SO long story short, there still is a rev matching going on with the clutch disengaged, it just has nothing to do with engine revs.

This is also why you can shift with no clutch.
When you upshift, it is easy to push the trans out of gear if you are not applying any load (not accelerating).
Then as you ease it into the next gear (clutch still engaged - attached to engine, engine revs falling) you put pressure on the synchros, but it wont let it in gear until they are matched. As the revs drop naturally, the gears will match up and it will slip right into gear with no grinding.

I dont do that regularly but I demonstrated it to my teenager while teaching him to drive stick, and he gets it perfectly.

[alan.chalkley]

What about warming up the transmission before any fast shifting?
My mt is stiff when cold (especially in winter) , but after warm up it shifts fine.

[steve99]

Originally Posted by stugray

They cannot deny you any warranty work just because you do the work yourself.
You can even do all of your own periodic maintenance as long as you keep accurate records and receipts to prove you did it.

With that said, I still let the dealer do my oil changes just so it goes in their record.

they will be friendly till you want a 10k warantee claim then they often change teir tune

unfortunatly they can and will use any excuse to deny warantee, then you have to prove otherwise and often expensive and timeconsuming process, that is not 100% you will win, take the easy way return it to stock its generally easier cheaper and less hassle even if yoy know its not related.

same deal on doing your own work they will use it against you , you may win you may not even if you did it properly the onus of proof is on you. that you did everything by the book,

most times its not worth the trouble or risk

[wheelhaus]

Originally Posted by stugray

I am trying to visualize what you are saying there and it makes sense.
On an upshift -
When you press the pedal and release the clutch (engage the throwout bearing), you decouple the engine from the trans input shaft.
Then when you pull the trans out of gear the output shaft and the input shaft are now free to spin independently.
The output shaft will keep spinning at the previous rate because it is connected to the rear wheels.
However the input shaft is not hooked to the engine, or the output shaft.
It is spinning under it's own momentum, and slowing (quite rapidly BTW).

Now you attempt to press into the next gear.
The input shaft needs to be spinning slower now to engage with the next gear up and the synchros will provide the friction to match the speed of the input shaft to the output shaft (now through a different gear ratio).
If you shift slowly then the input shaft may have slowed too far and the synchros have to speed UP the input shaft.
If you shifted really quickly, then the synchos will have to slow down the input shaft.

IF you wait exactly the right amount of time, the two shafts will be spinning at the right rate to engage with NO PRESSURE on the synchros.

SO long story short, there still is a rev matching going on with the clutch disengaged, it just has nothing to do with engine revs.

This is also why you can shift with no clutch.
When you upshift, it is easy to push the trans out of gear if you are not applying any load (not accelerating).
Then as you ease it into the next gear (clutch still engaged - attached to engine, engine revs falling) you put pressure on the synchros, but it wont let it in gear until they are matched. As the revs drop naturally, the gears will match up and it will slip right into gear with no grinding.

I dont do that regularly but I demonstrated it to my teenager while teaching him to drive stick, and he gets it perfectly.

Bingo!
Great description, BTW. It's difficult for some to visualize what's really going on inside that little mystery box. Here's an interactive animation showing the relationship between the gears and how a fork selects between two gears when you push the stick around. All gears are always turning with the drive wheels and are meshed to each other, but they spin freely until they are engaged to the shaft via a sliding collar. The input shaft is the free agent until it's clutched to the engine, or mated to a gear, or both (when you're driving the wheels).

Originally Posted by alan.chalkley

What about warming up the transmission before any fast shifting?
My mt is stiff when cold (especially in winter) , but after warm up it shifts fine.

I'm not a transmission engineer, I just love studying the machine and knowing how things work... I believe this is caused by the oil being a little more viscous (thicker) when its cold, making it harder for the synchro to develop the necessary friction. Thermal expansion may play a small part in this as well, because the tolerances inside a modern transmission are nuts. Once the oil warms it's a bit thinner, so the friction surfaces of the synchro can squish through the fluid a bit easier. You'll also get better mileage as it warms up as the gears and bearings don't have to squish the thick oil around, it'll flow more easily like water when its warm, and it splashes just enough to keep a nice thin film on everything.

The tranny will warm up faster when you're actually moving, causing a small bit of strain on the gears and fluid friction from the oil, sitting still it only warms from radiant heat coming from the engine block and exhaust. If you drive cold, just keep the rpm and load low without lugging.

This is also why a cold shift feels like you need to do it very quickly or your window is gone, and you're left wrestling with the stick and aimlessly trying to rev the engine, because the input shaft wants to slow down much quicker than normal. If this happens, go into neutral and clutch out while you're coasting, rev the engine, and immediately clutch in and select the gear while the rpm is up, it should drop right in. You just performed a basic double clutch by using the engine to speed up the input shaft, instead of trying to get the synchro to do it.

[stugray]

Originally Posted by steve99

they will be friendly till you want a 10k warantee claim then they often change teir tune

unfortunatly they can and will use any excuse to deny warantee, then you have to prove otherwise and often expensive and timeconsuming process, that is not 100% you will win, take the easy way return it to stock its generally easier cheaper and less hassle even if yoy know its not related.

same deal on doing your own work they will use it against you , you may win you may not even if you did it properly the onus of proof is on you. that you did everything by the book,

most times its not worth the trouble or risk

My dealer (Subaru) told me straight up: "NO PROBLEM with TRD parts".
Other's experience may vary.

And re: doing periodic maintenance yourself - I still use the dealer for the required maintenance interval work so they cannot question it later.
My experience comes from the late 90s Camry engine "sludge problem".
Many people were denied engine replacement under warranty because the oil changes were not performed at the dealer.
The ones who had the oil changes done by the dealer got new engines

[litemup]