NV 5600 rebuilt, clutch slip

[corprimo]

Our rig has been in at our son's place in Portland for the past year, and I recently had the NV5600 rebuilt after high temps and rattling noise in 6th gear while towing our 5er uphill in 6th gear. Lesson learned. Had the transmission checked at the shop before leaving Portland, no leaks, so up the Alaska Highway we went. About half way home to AK I started getting a bit of clutch slippage in 5th and 6th gear, so I lightened up, kept RPM's and Turbo Boost down and got the rig home. Unhitched the 5er, and no clutch slippage under heavy acceleration. Then I parked truck in garage, and there's a small oil leak from the transmission. So... . can a leaking front transmission seal cause the clutch to slip? transmission shop in Portland is 2500 miles away, so dealing with them is not going to be easy, but they seem reputable. (Oil that is leaking looks like that nice new Amsoil syncro manual transmission oil I had them put in as opposed to engine oil that might have leaked through a rear main seal. )

 

[HBarlow]

Yes, a significant leak from the front of the transmission could end up contaminating the pressure plate and clutch disc with transmission lube and causing the slip.

The clutch slippage under load could also just indicate a weak pressure plate or worn clutch disc.

I don't know any way to determine which is the cause or repair either without removing the transmission from the truck.

Good transmission shops often recommend replacing the clutch when the transmission is removed to avoid the labor costs of a repeat transmission removal.

 

[jelag]

When you had it out... . You didn't install a new pilot bearing???????

 

[corprimo]

Truck was in Portland, I was in Alaska, my son brought it in to a transmission shop in Portland 6 weeks ago to have the work done before I drove the truck back up the "highway. " I had spoken with the owner of the transmission shop last time I was down in Portland to see the grandkids in May and he was knowledgeable and seemed reputable. 12 month/ 12,000 mile warranty, and I had shop inspect the truck before I headed north, so have met the requirements of his warranty. Old transmission was running hot and starting to make a subtle rattling sound in 5th and 6th gear when towing uphill. Clutch seemed fine, so I didn't ask for any work to be done, and transmission shop didn't suggest it.

 

[corprimo]

Truck now has just under 75,000 miles on it.