Clutch "judder" or "shudder" causes?

[wicks]

Howdy. My 1994 NAS D90 has developed a "judder" or "shudder" - When engaging out of 1st gear usually when it is noticed. Very uneven engagement causing a repeating "micro-lurch". What's the official word for this phenomenon?

She only 24K miles on her, so I'm not thinking the friction plate is worn out, but never know maybe the PO (only one of them) was very messy with the clutch.

My first thought is of course rear main seal has made the dry clutch into a wet clutch, so the shudder is caused by oil slippage. But there is no oil dripping (crazy I know), and the oil pan/bell housing and in between them are completely dry.

Trouble I'm having is this bell housing has no inspection hole, just what appears to be a very small drain notch, which is dry. It's a 1994 with an R380. Zero visibility into the bell housing. Do people maybe just drill a hole into the bottom where most bell housings would have an inspection/drain hole?

 

[Napalm00]

dont drill a hole. if you really want to look in there remove the starter to look for oil on the sides of bell

could be chattering due to: oil contamination, improper driving technique, over heating due to towing or off-road, mechanical failure of disc or plate, PO not machining the flywheel or replacing the pressure plate when replacing the disc (being a cheapass)

if it not bad id just drive it and see if it gets worse

 

[wicks]

I'm pretty sure nothing heavy has ever been unbolted. I've only put about 500 miles on her so far (and I'm not the one guilty of improper technique haha, I'm a rev matching maestro).

A shop in Mass replaced the clutch slave cylinder before it came to me - wonder if adjustment or fitting of that could have an effect on chatter/judder/shudder?

If it was oil contamination wouldn't I be seeing oil out of that little weep notch? (Just added photos above)

I've also had old clutches behave this way due to rust on them, and have cured it by soaking the clutch with organic rust remover. If I had an opening, I could try...

 

[chuckc4]

The clutch could be juddering because it is worn from PO or when the slave cylinder was dying. Unfortunately, those are two big unknowns.

 

[Napalm00]

if the sale is bad or wasn't bled right it could also cause dragging

 

[wicks]

Clutch pedal feel is very good - definitely not dragging...any thoughts on a way to test without pulling the whole drive line apart to get a look? Squirt something up into the bell? Hah

 

[Napalm00]

starter hole and a bore scope

 

[MountainD]

I'm not certain that it is the clutch by the way you are describing it. Does it ever jutter in reverse? It is not uncommon, particularly at low speeds, to have the parking brake cause the judder. It typically happens in reverse, but can happen in forward gears too. Try dragging the parking brake ever so slightly--it could be the shoes in the drum causing it. It may just need to have a little more slack adjustment.

Or a bad clutch and a spring or something has popped out but it rarely just happens in one gear....

 

[chuckc4]

Are you sure you have an R380 Gearbox?

There were a lot of problems with the early '94's which had an LT77 box I think.

 

[evilfij]

Wait, I thought there was an inspection panel on the bottom quarter of the bell housing. I need to go look to make sure it is true on an R380, but I know it’s there on an LT77 out of a NAS110 (because I am an idiot and could not get the trans off before I removed it.

 

[rocky]

Judder on take off is a sign that the clutch is slipping momentarily as drive is taken up.
Not sure there is any ultimate solution to be found short of removing gearbox etc...

 

[wicks]

Yes R380 - down and right Reverse. Got to get out and take a closer look - does this flat steel piece with the three long screws come off between the sump and the bell (without pulling bell)?

I shall check the P-brake but I don't think I would mistake that for clutch judder...

 

[wicks]

Judder on take off is a sign that the clutch is slipping momentarily as drive is taken up.
Not sure there is any ultimate solution to be found short of removing gearbox etc...

Yes indeed it is - wondering if something is amiss other than worn out or broken friction or pressure tho, based on the 24K mileage etc.

 

[javelinadave]

24K means absolutely nothing since you don't know how the previous owner drove. My father in law burned thru my wife's clutch with probably that many miles on it over a weekend. Borescope it thru the drain hole and see what you can see or pull it apart and at that point replace the clutch plate, hardware and reface the fly wheel.
If you're handy you can do it yourself. Plenty of DIY YouTube videos online. Somewhere I saw a video of a guy who pulled the seats and the floor pieces off and used an engine hoist to support the transmission from above instead of pulling the engine or crawling underneath and using a transmission jack.

 

[jymmiejamz]

I think with a V8 truck it’s easier to just pull the motor, especially if you don’t have a lift

 

[MountainD]

I think with a V8 truck it’s easier to just pull the motor, especially if you don’t have a lift

Agreed. I’ve only done it without a lift, but have done every combo of disassembly both diesel and petrol, auto and manual and I personally remove the radiator/intercooler and pull the lump…. If it’s tricky, I take an extra hour and pull the fenders…not that hard and helps for LS and R2.8 in my opinion. Just cause the width. I save the time mating them. I do have some extra long guide studs still pain

 

[wicks]

You guys are just having fun scaring me. . Pulled a motor myself once, will never do it again. . Though, it might be better to go in from the driveline because that way you get the chance to re-seal everything in the line as well as the rear main engine seal.

If I do replace, is LOF the way to go? I don't mountain climb seriously anymore, and when I did my stock driveline in the 97 D90 never broke, but I wouldn't mind upgrading to a better clutch while at it.

 

[Napalm00]

If your rev matching like a pro like you say you are and you don't wheel heavily I would just stick with OEM. No need to spend the extra money on the extra heavy duty lof that will just give you increased pedal effort.

 

[jymmiejamz]

I’ve installed several LOF clutches so far and haven’t had any issues. The pedal feel is a little different than stock, but not overly firm or anything like that.

 

[Napalm00]

Yea not calling them bad ! I use one on my hybrid TDI. Doesn't sound like Wicks would use all that is what im saying