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Ive done some searching and found a few threads about a transmission whine, but nothing from those threads quite sounds like what I'm experiencing.
Just finished a T2 trans/diff swap on my S4 NA. Took it out for the first drive, and there were a couple things I noticed, first thing being a loud whine
It happens in all gears, while driving. Even coasting with the clutch in, going into each gear will result in a whine, regardless of whether or not the clutch is actually engaged. When in neutral its silent, whether the clutch is in or out.
Secondly, the clutch bites LOW. Like almost 1/4" off the floor low. The slave to clutch fork connection is tight. From what I remember, there should be some free play there. Could something be wrong?
Last edited by Cardinell; Nov 9, 2023 at 06:17 AM.
You wrote, in an earlier thread, that you installed an ACT clutch for an S4 T2 with a lightweight flywheel. Do to the aftermarket clutch and perhaps the flywheel, you will need to readjust your clutch pedal height and free play. I once installed an ACT clutch kit on my S5 and had to readjust the pedal afterwards.
did you change the slave cylinder to one for the T2 tranny? they are different (even though they will physically bolt to both trannies). if you have the correct slave, then as said above, try adjusting it.
as far as the whining goes ...
Originally Posted by Cardinell
Transmission was good before install. Would go through all gears easily.
It's an S4
Different shift lever, but I test fit the shifter lever on the trans before installing on the car
this is from your other thread, but did you determine it was good because you used it in another vehicle, or was this info provided by the seller?
You wrote, in an earlier thread, that you installed an ACT clutch for an S4 T2 with a lightweight flywheel. Due the aftermarket clutch and perhaps the flywheel, you will need to readjust your clutch pedal height and free play. I once installed an ACT clutch kit on my S5 and had to readjust the pedal afterwards.
I always thought you could only adjust the pedal further down, not up. Is there a procedure for this? I've never had to go through the process of doing it
did you change the slave cylinder to one for the T2 tranny? they are different (even though they will physically bolt to both trannies). if you have the correct slave, then as said above, try adjusting it.
as far as the whining goes ...
this is from your other thread, but did you determine it was good because you used it in another vehicle, or was this info provided by the seller?
are you sure you have enough oil in it?
Yes, it is a T2 slave, unless I was provided a wrong part. Not sure how to visually tell the difference between the two.
As far as "trans was good before install" I was referring just to the fact that it went through all gears smoothly, and I visually inspected the gears and, selectors, synchros, etc.
I have ~2.6 qts in there at the moment. Whatever capacity the FSM says. I filled it until oil came out of the secondary fill hole.
I always thought you could only adjust the pedal further down, not up. Is there a procedure for this? I've never had to go through the process of doing it
Yes, it is a T2 slave, unless I was provided a wrong part. Not sure how to visually tell the difference between the two.
it's possible you got the wrong one. stranger things have happened. however, the way to tell is look for the where the bolt holes are located on the cylinder. if i recall, both cylinders are about the same dimensions-wise, but the bolt holes are in noticeably different locations. you'd need to look at them side by side.
there's actually a fairly recent thread where someone posted a photo. i will see if i can find it and link it.
well, if it has oil, then i'm fresh out of ideas. maybe it's just beaten up and tired? maybe there is play in the main shaft?
it's possible you got the wrong one. stranger things have happened. however, the way to tell is look for the where the bolt holes are located on the cylinder. if i recall, both cylinders are about the same dimensions-wise, but the bolt holes are in noticeably different locations. you'd need to look at them side by side.
there's actually a fairly recent thread where someone posted a photo. i will see if i can find it and link it.
well, if it has oil, then i'm fresh out of ideas. maybe it's just beaten up and tired? maybe there is play in the main shaft?
Update:
I adjusted the clutch, and she still whines. Cold start, clutch out, at idle, it will whine and slowly get quieter as it warms up.
Once it's warm, it whines loud in 1st and 2nd, and will get quieter the higher the gear. I can't tell if it getting quieter is actually "quieter" or just the pitch is higher. When it whines in 1/2, it still whines with clutch in or out. The pitch increases with speed.
What does this sound like? Here is a video. Kept in first the whole time, clutch in and out throughout the video
In gear, the pilot bearing and the transmission shaft should be aligned, so there would not be any sound from it during that phase. The throwout bearing will be spinning when pressure is applied to the clutch. Both of those were changed, right? old ones would have basicly imprinted on the previous transmission and pressure plate, so reusing those would cause while as they try to wear back in.
Have you tried to remove the driveshaft, and row though the gears with the car in the air to see if the whine comes from the gearbox only?
Might also try loosening the bellhousing bolts, try to shake the trans or hit with a deadblow hammer and then retighten, might just be a tiny misalignment causing it and causing the whine as the input shaft is not perfectly straight. As long as the car is level, should not have gearoil come out the back
The description of its pitch rising with speed, what speed, can you clarify car speed or RPM? If first gear and 6000 rpm, it is on engine side of trans, but if fifth gear and doing 70 it is higher, on driveshaft side
In gear, the pilot bearing and the transmission shaft should be aligned, so there would not be any sound from it during that phase. The throwout bearing will be spinning when pressure is applied to the clutch. Both of those were changed, right? old ones would have basicly imprinted on the previous transmission and pressure plate, so reusing those would cause while as they try to wear back in.
Have you tried to remove the driveshaft, and row though the gears with the car in the air to see if the whine comes from the gearbox only?
Might also try loosening the bellhousing bolts, try to shake the trans or hit with a deadblow hammer and then retighten, might just be a tiny misalignment causing it and causing the whine as the input shaft is not perfectly straight. As long as the car is level, should not have gearoil come out the back
The description of its pitch rising with speed, what speed, can you clarify car speed or RPM? If first gear and 6000 rpm, it is on engine side of trans, but if fifth gear and doing 70 it is higher, on driveshaft side
This is very helpful, thank you for your response.
Yes everything is brand new. Pilot bearing and seal, Rear counterweight, lightweight flywheel, act clutch and new throw out bearing.
I may try out your suggestion and run through the gears with the car up in the air, driveshaft disconnected, however based on what you said further down in your response, it sounds like that may not help much
The sound is loudest in first and second gear, and the pitch increases with RPM, as high as I take it (to redline). The higher the gear, the quieter it becomes. Cruising the highway in 5th at about 3k rpm, I don't even notice it
If this is any indication, it also does whine on cold start, and quiets down as it warms up. But, while it's whining when cold, the whining stops when the clutch is depressed. Only starts to whine again when the clutch is released. I tried to get a video, but the sound is too faint to get on camera, over the sound of my exhaust
I think you identified it as the thing you hoped it wasn't, input bearing (or some other bearing in the transmission). When the clutch is out, the input shaft spins and no spinning pilot bearing or throwout bearing (unless you apply pressure to the clutch pedal), when you step on the clutch, the transmission is completely disengaged and the throwout bearing is spinning, so is the pilot bearing.
I think you identified it as the thing you hoped it wasn't, input bearing (or some other bearing in the transmission). When the clutch is out, the input shaft spins and no spinning pilot bearing or throwout bearing (unless you apply pressure to the clutch pedal), when you step on the clutch, the transmission is completely disengaged and the throwout bearing is spinning, so is the pilot bearing.
This wouldn't make complete sense though, as even coasting with the clutch in, it will whine as I row through the gears as long as the car is in motion. Once the car stops, no more noise.
The driveshaft is running the transmission when coasting, neutral or whatever gear, even with the clutch in.
My above post was with the car standing still.
Edit: If it whines while coasting with the transmission in neutral and the clutch pushed, it's not the input bearing. The input shaft should not be spinning.
Last edited by user 893453465346; Nov 20, 2023 at 05:25 PM.
Only other thing I can think of is when it comes to drive shafts and such, if the rear diff angle is off, it can put stress on the U joint. For example this is from the grassroots motorsport on how to do adjustment for the miata rear diff, might need to find if there is the same for the turbo rear diff since it is swapped in to replace the NA drivetrain? https://grassrootsmotorsports.com/fo.../103542/page1/
It would explain the sound changing with car speed and not just RPM only since it would be on that side of the transmission
The driveshaft is running the transmission when coasting, neutral or whatever gear, even with the clutch in.
My above post was with the car standing still.
Edit: If it whines while coasting with the transmission in neutral and the clutch pushed, it's not the input bearing. The input shaft should not be spinning.
Oh shoot, I didn't think about that, you're right.
It doesn't whine while coasting in neutral, clutch in or out. Only when in gear. So that would validate the input shaft bearing hypothesis.
Only other thing I can think of is when it comes to drive shafts and such, if the rear diff angle is off, it can put stress on the U joint. For example this is from the grassroots motorsport on how to do adjustment for the miata rear diff, might need to find if there is the same for the turbo rear diff since it is swapped in to replace the NA drivetrain? https://grassrootsmotorsports.com/fo.../103542/page1/
It would explain the sound changing with car speed and not just RPM only since it would be on that side of the transmission
When you get down there check on the tranny lower cross member. . . .I do know that if you crank down on that center bolt too much it causes problems, or at least it did for me..
This thread might give insight on part differences between lower S4 and S5 tranny mounts. In it, they talk about differences with the y connector.
When you get down there check on the tranny lower cross member. . . .I do know that if you crank down on that center bolt too much it causes problems, or at least it did for me..
This thread might give insight on part differences between lower S4 and S5 tranny mounts. In it, they talk about differences with the y connector.
I think I just gunned the nut on that cententer bushing when I installed it. Cannot find a torque spec for the life of me. How tight is it supposed to be?
Also, while trying to find the torque spec, I saw this part in the FSM that my car does not appear to have. What is this and is it necessary?
Also, looking at the FSM for the procedure of replacing the input shaft bearing, it seems like a giant PITA, and there are more than one bearing on the front side of the transmission.
2 questions come to mind:
1.How do I know which one is actually bad?
2. Is this job really as difficult as it seems?
it looks like an exhaust hanger to me, but ultimately, i can't say for sure.
Originally Posted by Cardinell
Also, looking at the FSM for the procedure of replacing the input shaft bearing, it seems like a giant PITA, and there are more than one bearing on the front side of the transmission.
2 questions come to mind:
1.How do I know which one is actually bad?
2. Is this job really as difficult as it seems?
in addition to you not knowing which one (if any) is bad, it would seem most prudent to just change them all if you do go ahead and pull the thing apart.
it looks like an exhaust hanger to me, but ultimately, i can't say for sure.
The exhaust hanger in approximately this location goes to the tailshaft of the transmission. Don't think it would make sense for Mazda to put another hanger this low
Originally Posted by diabolical1
in addition to you not knowing which one (if any) is bad, it would seem most prudent to just change them all if you do go ahead and pull the thing apart.
How difficult of a job is this? Some people say it's super easy, but looking at the FSM, it seems like I'm going to have to pretty much disassemble the whole gear box to replace all of these.
i have no idea how easy or difficult of a job it is. i've never owned an R-Type, much less tried to pull one apart. my comment was mainly to the fact that you share my lack of experience pulling a tranny apart, and it would be quite unfortunate if you replaced the wrong one and would have to pull it again to take another shot at getting the right one.
