Originally Posted by Fuergrissa (Post 3061902)

I recently replaced my throw-out bearing after the factory one had failed which involved removing the drive shaft and dropping the transmission. I replaced the trans oil at the same time.

After the work I am getting a severe vibration when accelerating at low RPM when the engine gets bogged. This is the only time the vibration is present but it is very severe. I know TOB's are a common job, has anyone encountered this before? Not excited to drop the trans again without knowing exactly what I'm looking for. I'm assuming something with the clutch or the DS carrier bearing but really don't know.

Thanks

Originally Posted by EndlessAzure (Post 3061947)

Did you install an aftermarket lighweight flywheel/clutch kit?

Originally Posted by Mr.ac

Chances are something is not torqued down properly.
Could be tranny mounts, drive shaft, who knows. It's one of those things where you just need to put a wrench and feel what's loose.

Originally Posted by humfrz

Welcome to the group, there, Fuergrissa .......... :clap:

So, you didn't have this vibration before you replaced the TOB .. ??

Did you take off the pressure plate and or replace the clutch disk .. ??

Did you do the work or did someone else do the work .. ??

Originally Posted by Fuergrissa (Post 3063049)

No, they were not removed



You are probably right, this was my assumption



No, it wasn't present before. neither pressure plate nor clutch were removed, just pulled the trans off, replaced the TOB and retaining clips, greased the fork pivot (was squeaking), and reinstalled with new trans fluid.

I did the work.

I marked the DS alignment to the differential so it went back on the same way, but the front yoke may have gone into the transmission with a different orientation.

It may be a few weeks before I can put it back in the air and investigate, so I just wondered if anyone had some different ideas. I don't think it's a balance issue because it does not increase in intensity with RPM. and if it were a harmonic resonance it would occur at the same RPM during all operating conditions. The fact that it is only in a certain RPM and only a certain operating condition (under load) makes me think it is probably something mounted too rigidly or not rigidly enough. Checking all the bolts is probably to best way to figure it out, but if anyone has another idea I would love to hear it.

Thanks

Originally Posted by Ultramaroon (Post 3063094)

Do you hear it, feel it, or both?

How did you support the engine?

Originally Posted by EndlessAzure (Post 3063433)

For my part, a little bit of both.

I don't recall supporting the forward part of the engine during the process

Originally Posted by Ultramaroon (Post 3063499)

The engine and transmission together balance on the engine mounts. When separated the engine will flop forward pretty hard. If you didn't support it, the exhaust pipe must have kept things in place. Perhaps a heat shield was bent then? Also, the engine bottom cover can make a hell of a racket if the screws back out. Once they've been removed, it seems like they don't like to stay tight. I use blue loctite on them.

Just a couple ideas. Try to record it for us. It might help.

Originally Posted by ermax (Post 3063826)

Anyways, I feel sorry for anyone who does that job without jacking the front of the engine.

Originally Posted by ermax (Post 3063826)

When I did my TOB I didn't support the front on the way off and spent almost 2 hours trying to get it off the lower studs. It wasn't until I said fuck it and pushed the jack aside and man handled it (not a good idea) that it came off. Once it was finally off I realized how far forward the engine tips which explained my difficulty getting it off. I supported the engine before putting it back on and WOW what a difference. I jacked it up enough and get it on the lower studs and then a single gentle push of the jack and the thing went right on. I could kick myself in the ass for skipping the front engine support.

Anyways, I feel sorry for anyone who does that job without jacking the front of the engine.

Originally Posted by Ultramaroon (Post 3063837)

After I get the back of the transmission separated, I wrap around the front of the engine and tie to the tower braces with a big fucking strap. :thumbsup:

Originally Posted by ermax (Post 3064154)

Oh that is a great idea. I used a wood block to get a jack on the water pump (not on the pulley) but really didn’t like doing it that way. Your method sounds way better.

Originally Posted by Ultramaroon (Post 3064174)

Thanks. Fair warning; it can be cinched up tightly enough to do damage.

Originally Posted by EndlessAzure (Post 3064179)

............No apparent issues at non-lug conditions.

Originally Posted by humfrz (Post 3064195)

Thanks for posting the videos ....... but, I can't seem to separate out the sounds that you're referring to......:(

No help, but, maybe your new clutch system just doesn't like to be lugged ....:iono:


humfrz

Originally Posted by radroach (Post 3129080)

@Fuergrissa @mabviper @EndlessAzure I can also confirm additional driveline vibration at low RPM's after I had my throw out bearing replaced. For awhile I just figured it was a symptom of a new part, and was mindful of keeping rpm's higher.

But a week ago I replaced my transmission mount (did a whiteline insert actually) and it pretty much removed that nasty low-rpm vibration. Try a whiteline insert or perhaps an STi transmission mount, see if it fixes your issue.

Originally Posted by radroach (Post 3129080)

@Fuergrissa @mabviper @EndlessAzure I can also confirm additional driveline vibration at low RPM's after I had my throw out bearing replaced. For awhile I just figured it was a symptom of a new part, and was mindful of keeping rpm's higher.

But a week ago I replaced my transmission mount (did a whiteline insert actually) and it pretty much removed that nasty low-rpm vibration. Try a whiteline insert or perhaps an STi transmission mount, see if it fixes your issue.

Originally Posted by EndlessAzure (Post 3064179)

@Ultramaroon @guybo @humfrz @Fuergrissa and any others

See below videos, taken from in-car (phone) and from Dash Camera. If necessary, I'll transfer to youtube for longer term preservation. Vibration severity much more apparent in Dash Camera footage
https://drive.google.com/drive/folde...cJ?usp=sharing


Modifications/changes of interest:

• TOB Service - Aftermarket pressure plate, clutch disk, flywheel, TOB, fork, and pivot: Verus/Velox Fork&Pivot, ACT SB7-HDSS Full-face Street Clutch with Streetlite Flywheel

Description of events:

1. Pull from 1st gear (no issues)
2. Shift into 2nd gear, bring speed/revs down to 1k rpm, 30% to 50% throttle pull to 3k RPM.
   • Noted flywheel chatter, very minor vibrations up to ~2.2k RPM.
3. Shift into 4th gear, bring speed/revs down to 1k rpm, 30% to 50% throttle pull until vibrations stop ~2k RPM.
   • Noted flywheel chatter, moderate vibrations between ~1.8k to 2k RPM.
4. Shift into 6th gear, bring speed/revs down to 1k rpm, 30% to 50% throttle pull until vibrations stop ~2k RPM.
   • Noted flywheel chatter, moderate/severe vibrations ~1.3k to 2k RPM.
5. Upshift into 3rd gear/2nd gear and allow engine braking.
   • Noted mild flywheel chatter between 3k and 2k RPM
6. Come to stop.

No apparent issues at non-lug conditions.

Originally Posted by TLD (Post 3129689)

My car does similar things, I thought it's normal when you lug it? I bought it used though so not sure if it does the same brand new.

Originally Posted by Ultramaroon (Post 3232416)

Mention function failed and I missed the recording. :(

After listening and catching up, it's not minor. If it rattles the rear deck lid, that's something heavy like engine mount, starter motor, front pipe support? @Mr.ac still nailed it in first response.

Originally Posted by Edwood (Post 3232573)

So you changed just the clutch and the vibration stopped?

Originally Posted by EndlessAzure (Post 3232502)

I never found out what it was. Checked the torques. Engine mounts, trans mounts, trans support were fine. Starter motor didn't rattle on start up, front pipe was fine.



My ACT clutch kit started dragging a while later, so I removed it all together and put the OE clutch back in