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Been researching this for a few months now... what's the general consensus on longevity of an aftermarket pilot bushing?
My 75k mile 1998 WS6 6-speed TA munched up its original pilot bearing in late 2012 and I had the clutch changed out as well as the slave and TO bearing. The shop I went with recommended a pilot bushing instead of replacement bearing on account of the munched-up input shaft tip. The car is a mint condition quasi-daily-driver (no rain since late 2000s).
I had also provided the fluid for a system flush. (important to note). The car ran ok for 2013 and 2014 except for a really low clutch engagement point, such that I occasionally had hard notchy shifting. In 2015 after a long highway drive (6 hours x 2 ) the car began groaning/buzzing during shifts... basically, when hot, I'm likely to get a loud buzzing groaning any time the input shaft is rotating (car in gear) and I'm moving with the clutch pedal down.
Took the car back to the same shop. The TO bearing looked bluish and was changed, and the fluid was changed to Synchromesh as well as yet another pilot bushing. Supposedly, the fluid was really dark even though I'd asked them to flush it out back in 2012. Got the car back and a couple of days later the buzzing came back full force. I'd have taken it back except that the shop was now moved to a much smaller location and I got the car back with a really deep scratch on the front fender so... we're done with that shop.
I can get the car to loudly groan/buzz with the clutch pedal down and in gear sometime just by hitting a bump on the road. I get the impression the noise is less likely to happen if I delay putting the car into gear during shifts (ie. let the input shaft spin down?).
Input shaft side-to-side play didn't seem excessive considering what I've read on here. Is there a trick to pilot bushings I'm missing? Or am I just better off going with a new input shaft and going back to the OEM pilot bearing setup?
The TO they claimed looked a little blue from heat.
The input shaft tip, after a little bit of manual polishing to smooth it out as much as possible.
I should add that the pedal is feeling a little "gooey" these days since the buzzing/groaning got worse. No problems shifting though, unlike during the 2013-2015 period.
I'm easy on the car so I don't think the components were even broken in... maybe 5k miles TOPS before the buzz/groan happened? And then not even 100 miles when the 2nd replacement pilot bushing went in...
Here's the photos I took of the disassembled clutch last fall. Sadly, I didn't get to see what the 1st replacement pilot bushing looked like.
About the noise, it's not so much a growl... it's really a deep groan. Like a groaning "whirr" sound, a sort of loud vibrating hum. Audible inside and outside the car. Not at all like the sound of bad synchros or some broken parts gnashing away... it gives me the impression of something not-smooth rubbing. However, it's ALWAYS the same tone... it's not speed nor RPM nor gear dependent. So it makes me think it's the input shaft wobbling/vibrating against sloppy bushing tolerances, if that's at all possible.
I did read something recently about late T56s (after Tremec took over) not handling pilot bushings too well, preferring instead the factory pilot bearing setup to support the input shaft along with the internal shaft bearing. Maybe improper/sloppy installation took out my input shaft bearing inside the tranny?
with the input shaft tip looking like that...it will kill bushings or bearings before a "smooth" shaft tip will. Might want to stick with bushings given the condition of the tip and understand the lifespan of the bushing will not be what "normal" would be
yes Tremac does recommend the bearing vs bushing for the T56. less drag.
slop from bad input shaft bearing is one common reason that kills pilot bearings or bushings
if you find it is hard to shift you may not be getting full disengagement. This will kill syncros and heat up TO bearing face due to the drag of the clutch not disengaging
To see if you do have a disengagement issue, jack up rear on car so wheels are off ground (use jack-stands). Start car, put in gear, hold in clutch, bring up RPM's...if rear tires move your clutch is not disengaging. You would then have a hydraulic issue. Perhaps whoever has been "flushing your hydraulics did not get all the air out.
Many also go with a TICK adjustable MC to resolve disengagement issues IF they have bleed hydraulics correctly and still have disengagement issues die to a failing MC
Actually, I don't really find it hard to shift, that seemed to have been cured by a proper fluid change (even though I asked it be done the first time when the clutch was changed, along with the slave and TO bearing). I wouldn't be surprised if that's what turned the TO bearing blue. *Supposedly* this should no longer be an issue (and it does in fact shift much easier).
Nonetheless I like the test on proper disengagement, I'll give it a go next time the car is in the air.
For the input shaft, given that the noise came back within a week of the installation of bushing #2, I don't think I can put up with this sort of "longevity". I guess an input shaft changeout is in my future... I suppose I should be proactive and look into swapping out the input shaft bearing as well, in case the shaft slop has caused excessive wear on the original unit?
(honestly I wish I'd have taken a video of the shaft "slop" when the tranny was out... I was told it was acceptable and have read similar statements about what sounded like similar tolerances, but I also read that this was only true if a pilot bearing was in use)
bushes lasted almost forever on most older cars....of course depends how often your foot is on the clutch, and there's a difference between crank sped and input shaft speed. At all other times the bush doesnt really do much but sit there.
I suspect the input shaft tip damage was due to a failed "needle bearing" pilot. It will now continue to eat bearings or bushings given how rough it is. "Maybe" it can be smoothed out more with emery cloth.
yes there is "some" play in input shaft normally but not much. The input shaft should just rest in a pilot bearing or bushing normally and either should last 100k mi or the life of a "normal use" clutch.....of course most of us drive harder than "normal".
A fluid I found to make shifts less "notchy", especially in cold weather and pre-warm up operation is Redline D4. Like any other lubricant, tranny fluid needs changeing
My pilot bearing failed in the same way and did similar damage to the input shaft. I didn't have money to fix it right (input shafts were not readily available) so I polished it with emery cloth and installed a pilot bushing. It lasted about 40k miles before symptoms returned.
Last summer I replaced the input shaft from the front for $150 and reinstalled with a bearing again. I'm sure that 90% of my clutch issues stemmed from missing a dowel pin. I had forgotten that it was missing and didn't have time to order one so I trimmed the chuck end of a 3/8" drill bit to use, since the diameter was perfect and it's hardened.
Absolutely no doubt about it, that input shaft tip got munched when the original pilot bearing fell apart in 2012. Here's a shot of the way it looked when initially disassembled in 2012... it does look like some polishing was done.
2012, the results of the OEM pilot bearing coming apart.
The original clutch was still looking quite meaty (because I really don't abuse the car much at all) but I decided to do everything in one go. Funny thing is that the TO bearing looks about the same colour-wise back then as it did last year... I'm starting to get this awful feeling I got taken for a ride with this shop (about which I'm hearing a lot of questionable stories these days).
So I know the shaft must have been polished a bit in 2012 (ed. note: that's what she said) and pilot bushing #1 lasted 3 years and maybe 5k miles or so, I'd need to look it up, before the noise started. After pilot bushing #2 (and a proper clutch bleeding), the noise came back within 40 miles.
I read something this week about installing the bushing a bit farther out from the crank to give the input shaft more support... maybe this is what needs to be done? Or maybe they installed the bushing backward? Or maybe polished it too much and there's too much slop in the installation now? I wish I had a lift and a proper trans jack.
Hoping to get it looked at by a decent shop next week, at least a preliminary exam. I'm looking forward to getting this car back into proper shape, it's been my reliable go-to workhorse for 18 years and is probably one of the last remaining factory stock LS1s on Earth and has led a really easy life compared to most cars of that vintage. No reason why it shouldn't last until my timely or untimely death.
I'll need to really read up on all the little bits and pieces, such as the mentioned dowel pins. Who knows what could have gone missing during the first "repair". It's just not obvious finding a local shop with good T56 experience... I *figured* that this shop I used would have been handy with T56s given their history with F-cars (I won't go into any further details to avoid mud slinging) but after many thousands of dollars and a deep scratch in my front fender, I'm disappointed.
I've even been able to reproduce the noise just sitting still with the clutch pedal pushed in... rowing the shifter through the gears quickly, I can sometimes provoke the moan.
It's even happened after backing the car down my driveway, car in gear (probably 1st) and clutch disengaged of course, with the car coasting backward. Popping it out of gear will always kill the noise. Also engaging the clutch will kill the noise as well.
And the noise is always the *same* loudness and frequency/tone. Always. Regardless of whether the car is at rest or coasting (but always in gear). So it's not input shaft speed related, but *always* when the clutch is disengaged.
The only constant source of movement is the engine running. Which has me wondering if something could be wrong with the clutch itself? (it's an OEM GM replacement - LUK, I think - ordered straight from a dealer in the US)
if you can use emery cloth to polish the end of the input shaft so there is no sharp edge "sticking up", I doubt the recessed part where there was damage would matter using a bushing. Basically so there is no sharp edge against the inside of the bushing
some do install the bushing so about 1/8" sticks out to basically move the bushing back further on the shaft. Your gouge is basically right in the "hero" area it contacts a pilot bearing/bushing so moving the bushing out I doubt will make any difference as the gouged part will still be riding on the bushing inner surface
polish it as good as you can and use a bushing
if you are missing a dowel that aligns the bellhousing to block...that will cause wear issues on pilot. You need the dowels to be where they are from factory
Do you think it would be obvious to a transmission shop that some dowels would be missing, if that was the case? I can see in photos what looks like 2 dowel pins on the transmission-to-bell housing but my photos from 2012 of the back of the engine are as fuzzy as heck... no way for me to identify where and how many dowels on that block-to-bell-housing mating.
Are the dowels a straightforward alignment deal? Meaning, just plop them in and they will automagically do the job of correctly aligning the bellhousing to the LS1? Or is there some finessing that is required, by someone with good experience?
Would measuring the input shaft play be enough to determine the health of the bearing inside the tranny? I'm assuming if I go with a replacement input shaft, I should opt for fresh bearing as well? How complicated is it to set up correctly? (I have read that one can replace an input shaft through the front of the transmission... does this also apply to the input shaft bearings?)
Lots of vague questions, I know... I'm just trying to plot the best (safest) course of action. I want my car back on the road ASAP and I want to minimize the chances of another set of incompetents messing up my car further.
You all have no idea how helpful you have been with your comments here.
Just an update: earlier this week my car finally went in to a local transmission shop, one of the owners seems to have extensive experience with T56s.
Diagnosis is the pilot bushing already destroyed... if that's the source of the noise, that means the pilot bushing got trashed within hours of installation last Fall. Guy says there was no grease on the bushing at all, says it's rare people do it when they install a pilot bushing in place of a bearing. Does this sound accurate?
I don't think he's checked the clutch for proper alignment yet so I can't report on whether the dowel situation is good or not.
He took a look in the tranny and says everything looks good. The old input shaft is going bye-bye because he says it was the cause of the pilot bushing getting destroyed (see pics above). Thoughts?
He was also quite satisfied with the input shaft play, both lateral and otherwise.
So hopefully the new input shaft and pilot bearing (yes bearing... after what I've been through, I'm kind of $hell$hocked right now as far as deviating from stock setup) will make everything quiet again. He said the tranny internals looked awesome and that if this doesn't fix it, it has to be clutch-related.
So my current question: is it possible for such a groan/whirring-buzz to originate from something clutch-related? I'm on the second TO bearing replacement (the first was "blue", likely from the fact the previous shop hadn't bled the system properly). Slave was new back in 2013 (?).
So I visited the shop today... the car was buttoned up and would have been ready to go for a test drive except they've been having a b*tch of a time getting the clutch master cylinder bled properly. Apparently it's a tricky task... any tricks to it that anyone can share?
As far as the work done: the input shaft was replaced and a new pilot bearing installed. The original one had no unacceptable play but the chewed up front end (see photos above) managed to chew up the pilot bushing that was installed in 2013... or 2015. I asked if it was possible for a pilot bushing to get munched that bad within 48-72 hours of operation, they said it was not likely and that this one was probably the one from back in 2013 and that nothing was changed in 2015.
So... this means those lying sack of s#it A-holes charged me C$1200 (more?) last year to replace the throwout bearing that was probably blued-up from their s#it clutch bleeding (they said the fluid was really dark... WTF, I asked them to flush it out completely back in 2013 when the clutch and slave were changed out!!!), and absolutely nothing else. The damned pilot bushing that was already whored out from 2 years of getting gnurled by the worn input shaft is probably still the one that was on there this time around. I mean, there was a TON of slop... no kidding the damned input shaft could flop around in there at a buzzing high frequency.
So if the noise goes away for good now, my next thing to consider will be the correct choice of lubricant for when I shove the old input shaft up the buttholes of the jackasses who ripped me off. After decades of patronizing them, and after thinking they knew their 4th gen **** because they were SLP's Canadian arm at one point (that's all I'll say on the matter... y'all knowledgeable people can figure out who I'm talking about).
Any time I touch the MC I either bench bleed it and/or use a MC bleeding kit. Another option is one that pushes fluid into the MC reservoir using pressurized air. Both the MC bleed kit and pressurized air kits are readily available at the local auto parts store or on amazon.
Trick that works well for me is to disconnect the master from slave and then use a Phillips head and bleed like rear brakes. About every three pedals refill the reservoir. Do about ten full pedal strokes. Then connect the slave and bleed the slave
05-17-2016, 11:21 AM
How long should pilot *bushing* last? 
and has led a really easy life compared to most cars of that vintage. No reason why it shouldn't last until my timely or untimely death.
