My truck finally gets to go on the hoist tomorrow and see WTH is wrong with the clutch. What I need to know is if I still have the factory 13" clutch in my truck will a 12 1/4" bolt on? Will the HD version of the 13" fit into the center of the flywheel? I ask because the 12 1/4" that they offer is a lot cheaper and is rated to hold a lot more then this will ever see (at least in the near future), and if I get the HD option it says the center hole, not the pilot, but where the bolts go needs to be machined to fit the HD hub? I need to know so when the mechanic calls me I can tell him what I want, and know it will work without any other mods.
DS79

 

12 1/4 will bolt in, the heavy duty one is for 4:10 gears and most places will not sell it to you if you do not have 4:10s, or thats what they told me, i'm running the 12 1/4 one thats for 3:54s and its holding fine (so far) mines a luk clutch with valair friction material. even held 1 seld pull, i'll see if it holds another

 

So if I get the 12 1/4" I won't have any issues with the bolt hole lining up, sweet. Why do they sell flywheels then that are drilled for either one then? Or is it so you can use them with the 5600? BTW I have 4.10's and duals
DS79

 

if you get the heavy duty one that they use for tow trucks with 4:10s i think the center of the flywheel has to be machined because the hub in the heavy duty clutch is too large to fit the flywheel, thats what i was told and the heavy duty one is saposed to have ceramic buttons

but the lighter duty one should bolt right in

 

Ok thats what I was thinking. So you like your clutch? Do you tow a lt with it? How are its manners with a load on, and going in reverse?
DS79

 

I am going through all of this right now.

The factory clutch in a 1st gen is a 13" with a cast iron pressure plate.

A stock 2nd gen is 12-1/4 with a stamped steel PP.

They use the same bolt pattern. You cannot get a 13" stamped steel pp to fit on the flywheel. There just isn't enough meant there to do it.

On a 6 speed they went to a true 13" stamped steel pressure plate and made the flywheel larger to accommodate. Thats why you need the starter spacer, they moved the ring gear towards the front of the engine, so that the PP can bolt on directly behind it. If you ever look at the 2 flywheels side by side you will see what I am trying to explain.

I would stay with the stock Sachs, and have the roller pilot bearing put in.

Look here:
http://www.valairinc.com/performance/12nv4500.html

They offer a ceramic disc one as well, but I am sure you need to machine the flywheel for the spring hub. I specificaly asked them (Valair) if I had to do this, and they said" I doubt it, most 1st gens have a different flywheel, and it just fits"

Thats sounds a little iffy to me, so I went somewhere else.

 

i like it nice and smooth all the time, might be a little grabby but if it is i dont notice it. loaded its fine and i tow all the time 10k+ no issues yet.

pic of my normal load http://i289.photobucket.com/albums/l...s/DSCF3989.jpg

video of towing, shot this video right after i took the pic, http://www.youtube.com/watch?v=2N0XEOQko1M dont know if it helps or not?

this is how it did sled pulling http://www.youtube.com/watch?v=cEGtstaWCEQ&feature=user

 

Trying to go cheap on a clutch = paying twice in the end after you have to get a real 13" unit after the cheap 12" unit doesn't even hold as good as the high mileage stock clutch

 

Please don't buy ANYONES 12" clutch. The centers break.

 

I measured the spring hub pocket tonight. It meaures 6-1/2" where it is still a 1/4" deep. Valair said you need a 7" x 1/4" deep hole to clear.

 

Thanks a lot for the info guys, I am getting the OEM replacement clutch kit from Valair Part# NMU0087. Should be in early next week. Is thepilot bearing something I should look into having put in or is it mostly for the higher performance engines? Need o know by morning or it will get the bushing it comes with.
DS79

 

i think it depends on if you sit with the clutch pushed in alot?
i'd stay with the bushing, they have been used for years why change?

 

Last year I had to drop the trans because the throw out bearing went out. When the clutch was pulled the pressure plates had 50% life lest after 150K of towing big hills and lots of city driving. So while the trans was dropped I put in a new clutch, I have a luk and its fine for now. I didn't know that you could still but the sachs at the time so in the future I will put a sachs in. I like the way it pulls and drives.

 

I don't sit with the clutch on a lot, try not to, besides your leg gets tired if you do it to much. LOL I kinda figured that the bushing works fine since new so why bother, but thought I would see if it held any real benefits.
DS79