to lube or not lube splines

[Jim S.]

Getting ready to install the tranny into my newly rebuilt motor and new Luk Clutch.

I know a lot of you have reccomended Luk ,so I went that way .
I do however have one question. The kit comes with a small amount of Graphite, or black grease, that says it is for lubricating the input shaft splines. I went to their tech page and it says "Lubricate the input shaft splines with a very small amount of high-temperature grease". Is that a good or a bad Idea ?

I looked up everything I could find in the archives, and found tons of info on how not to grease the end of the shaft when using a brass bushing. On how to use a sparing amount of grease on the pivot ball and fork . On how grease contamination on the pad can ruin your day ,etc etc etc . However found nothing on either the pros or cons of lubricating the splines, lightly or otherwise .

Your thoughts please ,

Jim

[Tracy C.]

Re: to lube or not lube splines

Jim,

Interesting question, but any application of grease on the shaft should be a light film or less as I would imagine centrifugal force would tend to sling grease droplets outward and possibly onto the clutch disk.

tc

[Domenic T.]

Re: to lube or not lube splines

We always kept the shaft dry as it only has to get the shaft once, if you follow.
There is no movement to speak of between the input shaft and disc splines.

The only thing I can think of for the use is to aid the input shaft to slip thru the spline.

DOM

[Pierre J.]

Re: to lube or not lube splines

I usually use a small amount of anti-seize on the splines. Never been an issue

[Gary R.]

Re: to lube or not lube splines

I use grease on the throw out bearing and retainer. I never used it on the splines, never had an issue. A little might be ok but again I never needed it. The bronze bushing a little oil, not much. Be sure it's not magnetic,many new ones are. Look over the bearing retainer too, any step and it should be replaced now before it breaks.

[Jim S.]

Re: to lube or not lube splines

"Interesting question, but any application of grease on the shaft should be a light film or less as I would imagine centrifugal force would tend to sling grease droplets outward and possibly onto the clutch disk."

tc

Tracy,
Thats what I was thinking , so why advocate it ?




"We always kept the shaft dry as it only has to get the shaft once, if you follow.
There is no movement to speak of between the input shaft and disc splines.

The only thing I can think of for the use is to aid the input shaft to slip thru the spline."

DOM

Dom,

I do follow , thats why I didn't get why they asked for it . You must be right in that it is only for ease of application.



Thanks to Pierre and Gary also, for your input .



The only other reason I can fiqure, is to make it easier to take apart later on down the road ????


Jim

[Chuck S.]

Re: to lube or not lube splines

...The only other reason I can fiqure, is to make it easier to take apart later on down the road ????...

In my opinion...probably not the primary reason.

My experience with other types of machinery shaft fits suggests it's to prevent "fretting corrosion", a type of mechanical wear that occurs whenever you have constant load reversals at a dry shaft joint.

It doesn't matter that there is little clearance in the fit...if there is ANY clearance in the presence of vibration, there is risk of the metal being constantly "welded" together under loading, and broken apart when unloaded, resulting in erosion of the metal over time. Lubrication will reduce this tendency as long as the lubricant lasts.

I have seen straight coupling fits with 0.0005" clearance (so tight, it's virtually impossible to assemble with human hands) "eaten alive" when run at 4000 rpm "constant" speed. Of course, the speed was not truly constant...normal process load variation produced a constant torsional vibration.

An automotive clutch plate, especially in an old Corvette, will never see that much continuous service. In your place, I would probably use the lubricant as directed, but in a thin film.

[Jim S.]

Re: to lube or not lube splines

Chuck ,

I like my short , non-technical guess better , but ok, ,that may be a good reason too !

In fact, I think we have a winner !

Thanks for that info !

Jim

[Bill M.]

Re: to lube or not lube splines

If the splines got rusty and the disc couldn't move at all, it might result in a hard shift; the input shaft would tend to run at the speed of the flywheel. But I've never had that happen...

[Clem Z.]

Re: to lube or not lube splines

with the trans out try sliding the disk back and forth on the splines. if there are any "rough" spots use a honing stone on the splines. back in the corvette racing days we used lapping compound to lap the disk on the trans splines for better shifting. of course clean off the lapping compound before you install the set up

[Jim S.]

Re: to lube or not lube splines

Splines lightly lubed, tip lightly oiled ,bearing and pivot ball lightly greased as well .

It went in tightly, but in went in !

Thanks again all !

Jim