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Discussion Starter · #1 · (Edited)
Hey guys, I just put in a new southbend double disc clutch with new hydraulics and also had the 5th gear nut welded. I pretty much have to muscle it into every gear now. Is this supposed to be like this? Before upgrading it was the smoothest and easiest shifting tranny Id used.
 

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VP of the dry side
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Did you install a bigger input shaft?

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Discussion Starter · #3 ·
Yes we put in a larger input shaft
 

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Did you put graphite on the input shaft and clutch splines?

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Rescue Tower
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Hey guys, I just put in a new southbend double disc clutch with new hydraulics and also had the 5th gear nut welded. I pretty much have to muscle it into every gear now. Is this supposed to be like this? Before upgrading it was the smoothest and easiest shifting tranny Id used.
Try adjusting the rod on the hydros. Increase the throw out a bit to see if that improves things. Should shift smooth, with possible increased delay between gears.
 

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Cummins Nut
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Mine was noticeably harder to shift after I installed my dual disc. I tried adjusting the rod but it didn't help in my case. I tried several things, and the one that helped the most was adding an extra 1.5 qts of fluid to the trans. I'll be removing the amsoil soon and putting mopar fluid back in to see if that helps get the little bit a catch back out of the shifts.
 

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Discussion Starter · #7 · (Edited)
Graphite wasnt used, as southbend doesnt mention it but it seems like thats what most guys say to do. Its also has the extra fluid already in. The truck is really a pain in the to drive now. Adding all the power mods seems kind of pointless now when you have to take a few seconds to get into each gear, at which point youve just been smoked by a civic.....

Also another quick thing. The clutch pedal is also much harder to press now. I understand there is much more mass with the clutches but thats what the new hydros are for right?
 

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Most people leave the stock hydros. Honestly the 12v trucks already have heavy duty hydraulics. No need for them except maybe an adjustable rod. At any rate, what i did on my install (got this info from dan at Valair) was take my input shaft and slide the disks on them and see if they caught anywhere. It they do file the corners of the splines on the disks to take off any sharp edges. Then check again. Keep doing this until the disk slides really nice on the shaft (but don't go bat s crazy) Do that to both disks. Then on the install put on the graphite (spray tore is easiest) and out it on the input and clutch disk splines.

After install mine drove like a dream for about 50 miles. Then started shifting slower and slower. Then started getting grabby and aggressive. After a few good launches (after 400 miles) it smoothed out. It still shifted somewhat slow. But you definitely get used to it. How to drive it and what rpms it likes to shift at. It takes time to get used to. Now, my clutch has about 2000 miles on it and is really starting to smooth out and shift much quicker. Maybe I'm learning to drive it. But i think its manners have just been improved. I can tell its not so grabby.

Hope that long winded explanation helped some lol

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What ^^^^ he said.
I didn't file anything when I put Valair organic DD, but I used graphite spray. It definitely slowed down the shifts. I learned not to shove it in each gear, but give it some pressure and wait for it to fall in on each shifts. This clutch is not for racing, but to hold your big power while towing. I sold the truck when clutch had 3-4000mi on it and it got a lot better at that time, but still slower than stock shifting speed.
 

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Discussion Starter · #10 ·
OK thanks guys! From what Ive gathered online and from you have said, graphite and filing burs/sharp edges will make it a bit better. Its funny how Valair mentions these things but not southbend.
 

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Rescue Tower
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OK thanks guys! From what Ive gathered online and from you have said, graphite and filing burs/sharp edges will make it a bit better. Its funny how Valair mentions these things but not southbend.
Honestly that is standard procedure with any clutch. All splines (internal & external) must be clean & smooth. You can use grease on the splines, but since many people apply to much which results in clutch contamination. The safer practice of graphite has largely been adopted. Graphite also doesn't attract debris like grease does.
 
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