So last week my clutch went out and so I bought a new clutch for the truck (Southbend Single Disk Feramic clutch if anyone is wondering) and I threw everything onto the truck up until reinstallilng the transmission itself. Just got done packing the throwout bearing and input shaft (high temp wheel bearing grease) and I realized the clutch is in the truck and everything already and I don't want to take it out again to get greases in the splines since I was told there needs to be grease in the splines of the input shaft and to use the clutch to spread it in the splines and I assume get some in the splines of the clutch as well. Make sense? I hope it does because my question is do I need to lube the splines of the clutch when reinstalling the transmission if I lube up the input shaft good enough? Anything helps, thanks!

 

TL;DR: Do I need to lube the clutch splines at all or will it work just to throw some grease on the input shaft and install the transmission?

I advise to not grease the splines on the input shaft. Grease will only attract clutch dust and will cause the disk to not float on the input shaft as it should. Also over greasing the pilot bearing and greasing the splines is not recommended because of the high chances of grease contamination of the disk friction material.

 

Eaton specifically states in their clutch installation guide to not grease the splines of the input shaft for the reasons I stated above and their clutches are known to go 800k + miles.

 

This screenshot posted below is straight from Eaton which is what I'm basing my advice on, see number 15. I would check with Southbend and see what they recommend with their clutch. I've always been taught grease on the input shaft splines is a big "NO NO".

 

 

 

  no grease, no problem.

 

What would that grease look like after 5 years?  Hard, may be sticky, and definitely dirty.

Then any grease that is slung off the shaft will most likely land on the friction disc. I brake clean the input shaft that's all.

What about greasing where throughout bearing is sliding on

6 minutes ago, Dieselfuture said:

What about greasing where throughout bearing is sliding on

 

Throwout bearing should already be greased when you get it. Like my Southbend throwout bearing was already packed with grease. Just clean the sleeve it rights on and slide on the new throwout bearing. 

1 minute ago, Mopar1973Man said:

 

Throwout bearing should already be greased when you get it. Like my Southbend throwout bearing was already packed with grease. Just clean the sleeve it rights on and slide on the new throwout bearing. 

I guess the sleeve it rides on is what I'm thinking, I did some clutches in passed on cars and few trucks and always greased that. One time I didn't and with in few months clutch got hard to press, tore it upart and there was a groove cut in that sleeve. 

I greased that sleeve on mine.

Yes that what I'm talking about there that throwout bearing has grease in the inside of the part that rides on the sleeve. Mine was already packed and ready. Slide it on and it automagically greased the sleeve for me. 

To grease or not to grease...  this is one of those topics that may leave some undecided.  Good arguments can be made for both sides.   In the end one will have to make the decision based on information from  service manuals, professional and non-professional experience, and your own experience. 

 

Personally, I have always put a very thin coat of grease on the transmission input shaft splines and the transmission front bearing retainer sliding surface for the release bearing.

 

From the FSM for 2002 truck.

 

- John

 

 

Edited November 2, 20186 yr by Tractorman
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With the heat and clutch dust accumulation in the bell housing that will cause the grease to thicken and get sticky I think grease will do more harm than good and cause the disk to not float on the input shaft splines as designed. Since Dodge didn't build the clutch or transmission I'd be looking for manufacturers instructions. Just like I'll always follow Cummins procedures before Dodge when diagnosing a Cummins engine, I have found variances between Dodge and Cummins procedures. 

1 hour ago, 04Mach1 said:

With the heat and clutch dust accumulation in the bell housing that will cause the grease to thicken and get sticky I think grease will do more harm than good and cause the disk to not float on the input shaft splines as designed. Since Dodge didn't build the clutch or transmission I'd be looking for manufacturers instructions

 

I think you make a good argument here about the grease thickening and attracting dirt, that is why I use a very thin film.  Luk is the manufacturer for the clutch I just installed in my truck and they say basically the same as the FSM.

 

- John

 

From Luk,

Technically... The is no reason to really worry about the friction disc being lubricated. If you figure 99.9% the pressure plate is clamped down on the friction disk and its not going to move anywhere. Then when you press the clutch pedal to release the disc isn't going to move a whole bunch. Just the room between the flywheel and the open pressure plate. Why would it move very far? 

 

Now the throwout bearing that moves quite a stroke on the sliding collar pressing the pressure plate release fingers. I can see the throwout bearing sleeve being greased. Like mine supplied from South Bend Clutch it was already to go just install. Grease was already supplied.

Edited November 2, 20186 yr by Mopar1973Man

2 hours ago, Tractorman said:

 

I think you make a good argument here about the grease thickening and attracting dirt, that is why I use a very thin film.  Luk is the manufacturer for the clutch I just installed in my truck and they say basically the same as the FSM.

 

- John

 

From Luk,

 

Good point. So my advice would be to follow the clutch manufacturers install instructions since they will be eating the warranty if the clutch fails before warranty period has expired.

 

For educational purposes I looked up Exedy's install instructions and they too call for a "light" coat of grease on the splines of the input shaft of the transmission. I suppose what I would do is apply "High Temperature" grease to the input shaft splines then slide the disc back and forth on the input shaft splines and wipe the excess grease off the input shaft splines leaving only the thin grease coating on the input shaft if that's what the clutch manufacturer instructions say to do.

I just did a clutch, I just used a bit of spray on graphite on the splines and  throwout bearing . Dry lubricant so it won't hurt the clutch discs. Probably won't stay on very long but doesn't hurt anything and provides some friction reduction over no grease. 

17 minutes ago, 04Mach1 said:

So my advice would be to follow the clutch manufacturers install instructions since they will be eating the warranty if the clutch fails before warranty period has expired.

 

Now that's good advice!

 

- John

On 11/2/2018 at 7:44 PM, 6cyl$$pit said:

I just did a clutch, I just used a bit of spray on graphite on the splines and  throwout bearing . Dry lubricant so it won't hurt the clutch discs. Probably won't stay on very long but doesn't hurt anything and provides some friction reduction over no grease. 

This!