DansYellow66

I didn't find that exact warning on my paperwork or on their website but there was a somewhat generic warning to test fit discs on flywheels to make sure they don't make contact with the flywheel bolts.

Definitely a possibility. With the clutch in at idle the clearances might be enough to avoid contact. With the clutch all out, it's locked tight so no noise. When releasing clutch shudder, noise, etc. Could be the issue. Looks like I'll probably be pulling the whole thing apart again.

One problem is someone was telling me the other day that its very difficult to just purchase a new clutch disc w/o buying an entire clutch set. I might be adding to my collection of barely used drive train parts up in the attic.

wmf62

[QUOTE=DansYellow66;One problem is someone was telling me the other day that its very difficult to just purchase a new clutch disc w/o buying an entire clutch set. I might be adding to my collection of barely used drive train parts up in the attic.[/QUOTE]

absolutely positively not true.... Summit lists a total of 1,408...

https://www.summitracing.com/search/...Clutch%20Discs

Bill

DansYellow66

Yeah - I went to Summit and Ram earlier and found the same thing. Not sure where he got that impression.

DansYellow66

After a month of repairing/cleaning up after termites, vacation in Hawaii and my back going out, I finally got the transmission back out today. My first two suspicions proved negative but a third - the pilot bushing - may be the culprit. I also realized I forgot to lock down the inside nut on the adjustable fork ball - not sure if that could cause some chatter/shudder or not.

Hopefully someone can give me some ideas on this.

The good. The throwout bearing was hooked on the fork OK. The clutch disc hub was installed towards the transmission and I don't see any sign of contact with the flywheel bolts from the other side. Putting the disc up on the flywheel, it sits flush and has some clearance to slide around without contact.

The bad. I stuck a plastic alignment tool in to hold the disc while I removed the pressure plate and when I pulled the tool out the pilot bushing came with it. I stuck it back in and it slides into the crank easily. When I originally installed it I stuck it in the freezer and it easily installed and I figured as it warmed up it would seat tight - never went back to check it.

I don't see any issues on the flywheel, clutch or bearing retainer.











The pilot bushing is from 5-speeds and I don't know the origin but it's non-metallic. It measures 1.094 inch outside dia.



I don't have a caliper that will reach the crank recess but I used an inside caliper and a bore caliper and got pretty much the same reading of 1.101 inch to 1.102 inch so the bushing is several thousands loose.





The inside of the bushing is .001 greater than the input nose diameter of the input so it was good.

What is the inside bushing register in the crank supposed to measure? Has anyone experienced what a loose pilot bushing feels like - shudder and a bit of noise when letting out the clutch?

This McLeod TO bearing rides pretty loose on the fork. There is clearance in the groove between the fork fingers. I never paid much attention to that in the past. Normal?



I plan to call Larry and D&L Transmission and see what he thinks.

Powershift

Dan:

Your pilot bushing OD is correct per GM specs (1.093-1.094 in). It should have about 2-3 thousands interference fit in the crank.

Your pilot bushing ID also sound about right, and it should also have 1-3 thousands clearance (gap) to the input shaft nose.

You may have to buy a bushing with the same ID and with a bigger OD and then turn it down in a lathe. DO NOT machine the ID of the bushing as it will close up the oillite pores............but this does not matter for the OD. Larry may also know if they already have a conversion bushing for your engine. You have the specs from your engine to give him.

Larry

SupremeDeluxe

Those localized dark spots on the flywheel and PP don't look normal to me for a setup that has had only a few test miles (or less) on it.

I had a situation similar to this with a LUK replacement clutch on my 435 car, and what it turned out to be was that the pressure plate cover was not seating fully against the flywheel, as one of the 6 bolt holes had a shallow countersink. The bolt shoulder was stopping at the bottom of the counterbore, leaving about a 0.020" air gap between the cover and the flywheel. The result was a hellified vibration on engagement.

As Larry pointed out, that bushing is the right size but for some reason the crank is big. I'm not sure where you'd get a bushing that is O/S on the OD, but it's probably out there somewhere. If you are going to do it, make sure whoever turns it makes sure to indicate off the ID so the new diameter and the ID are concentric, or you'll have a new issue.

When I put mine in it was very, tight, I had to freeze it and drive in with a tool I made.

DansYellow66

Well - that's what I was afraid of. Not sure what's the deal with my crank - it's a stock forged GM crank. I remember dealing with this somehow about 15 years ago when I last had the clutch out. I may have loctited it in back then. I had to thread it and crank it out in June.

Larry at D&L was going to look up the specs. He said he had custom made a few. I guess my choices are to have him turn one down or do the Loctite thing again.

DansYellow66

I noticed those too. They are very superficial and I literally only drove it around the block. It's a brand new McLeod pressure plate and new RAM flywheel. The disc is an older Centerforce disc I've had in it for about 3000 miles. I think I will just get a new McLeod disc while I'm at it

Disc fit to the flywheel fine and the pressure plate bolted down fine and tight against the flywheel also. But I may have purchased new bolts for the pressure plate so I'll double check them.

Powershift

Although you can make an install tool for the pilot bushing, a cut-off original transmission input shaft will both install the pilot bushing and correctly align the disc. Also makes sure everything will fit correctly during the installation. I bought a Muncie used input shaft for $35 and had the machine shop make me the install/alignment tool. Worth every penny.

AGE Autogear (forum sponsor) sells an oversize oillite pilot bushing with an OD of 1.150 inches. Same ID of 0.593. Also same depth at 0.720 inch. Part #0-127-018. They say "turn OD as required" as a footnote.

Larry

SupremeDeluxe

I think the input shaft would be just fine as an install tool. In my case, the bushing fit was tight as a piano string and I was only able to remove the old bushing by running a bolt into it. I wanted to use all the face area of the bushing that I could to drive the new one in, thinking that I didn't want to limit myself to the surface area of the shoulder on the input shaft.

I think the right way to fix this is to get the oversize bushing and turn it to fit. Using retaining compound to overcome a fit that is 0.006-0.008" loose is going to result in the bushing bore being off center, introducing another possible source of vibration and creating unnecessary wear on the input shaft bearing.

buns

I checked two cranks and they both measured 1.088".

DansYellow66

That is probably my best option. I would need to get it down to 1.104 I'm guessing for a press fit, or .046 smaller. I wonder if fitting it in a drill press and spinning it against a flat file would work for that? Go slow and measure often.

I have my original Muncie input for an alignment tool but it's still a good input/gear that could be a rebuild part for someone someday - so not something I want to pound on.

Thanks

DansYellow66

Anyone think the loose fit of the fork and TO bearing is an issue. Don't think it's part of the main problem but seems they typically don't have that much looseness in the fit.

wmf62

IF you can make sure that the bushing remains round and concentric...

wmf62

I don't know how 'loose' loose is, but it would have to be a gross fit for it to rattle around and beat on the bearing retainer..

Bill

Mossy66

Might work. But for all the work you have to do if it doesn't, I would have someone do it on a lathe. In fact, have them do two or three for later.

Gerry

Mossy66

I doubt it. Could it be tightened up? If it was me, I'd probably get a new fork just to eliminate it as a possible problem.

Gerry

Powershift

To eliminate the shoulder contact, if you think it can be an issue, is to make up a brass flat washer that just fits over the input shaft nose and has an OD slightly less than the pilot bushing.

Easy and quick to do, and provides full face contact. Put the entire assembly ( cut-off input shaft and pilot bushing) in the freezer overnight to cool, and the input shaft mass will help keep things cool during the bushing install.

But making an installation tool is also good way to go. Also not hard.



Larry

Powershift

Larry

DansYellow66

I called AutoGear and talked to Jason about ordering a couple of the GM oversize bushings and turns out they have not actually produced or outsourced any of those yet. The catalog sheet I downloaded on bushings was from Feb 2016 so I guess they were anticipating way ahead.

He is checking to see if they have any stock that they turn down for me. Waiting to hear.

What kind of interference fit should this bushing have? I tried an experiment of putting my old bushing in the deep freeze for awhile and it only shrank up .001 inch. I'm thinking about .003 inches larger than the crank register at room temp - maybe .004 - but Buns mention of two cranks measuring 1.088 inch kind of stumps me. Cramming a 1.094 bushing froze to 1.093 sounds a little too much.

If he can't come up with any stock I'm not sure what the next move is.