Rebuilt NV5600 issues

[Cattletrkr]

After putting a whopping 300 miles on my freshly rebuilt NV5600 (trade, not my original transmission), I no longer have much for synchronization of 4th gear. If I wait a little extra longer I can go 3rd to 4th, but I absolutely have to double clutch to go from 5th to 4th w/o sickening grinding. I've never had synchros go bad. Is that what I've got here? I have to call the shop tomorrow and raise holy hell.

Yippee.

 

[Gary - K7GLD]

The NV-5600's vary in what lubes they will work with as far as syncro function is concerned - whatever lube you now have in yours, it's NOT working, and for starters, you need to try something different.



IF you are trying the Amsoil you have listed in your sig, or some other, Non-OEM lube, I'd try the OEM stuff to see if it will improve shifting - the OEM DC stuff is the only thing I've found so far that will work in mine without grinding gears...



Good luck.

 

[MMeier]

Oh boy... let the fun begin!! Still fighting with the A Holes that did my last 5600 over 700 bucks for a clutch that was no good. :-{} Not too mention the TRANSMISSION itself still does not shift worth a crap once it gets warm. #@$%!

 

[jelag]

I own an 04, 3500 dually with over 245K miles... at about 235K miles the NV5600 died... we pull a trailer that weighs up to 22K lbs... . 85% of the time... .

The transmission builder sent me 3 bad transmissions, all had excessive clearance problems and made a whole lot of noise... . the first one had the wrong input shaft... . seems that they wanted to install an 1 1/4 input shaft instead of the 1 3/8"... . NMeier, make sure your transmission has the correct input shaft... . it will destroy the clutch if the smaller one is on the transmission... and it goes together very easy..... also note that it will vibrate to beat the band as the 1 3/8" hub in the disc will fit onto the 1 1/4" input shaft and and each time the clutch locks up its out of balance. . The 4th transmission is now in the truck... . it makes more racket than our 05 with 80K miles... but the supplier finally caved in and gave me a 3 year unlimited mileage warranty to keep the one in the truck.....

Cattletrkr, look to see of your oil has turned the color of bronze..... if so the oil is not correct and the lack of lubrication, (read incorrect lube) has caused failure...

I wanted to have one of our customers, PTO Sales, who has stores in AZ, CA, NV, UT do our NV5600 but we didn't have time to either ship it to them or get an exchange... . after all the screwing around we did with a vendor here in town we could have had them do it for us..... PTO Sales usually has a gear guy in each store besides the on the shelf exchange transmission they carry... . PTO sales has a store in Las Vegas... . I've been to all their stores, we sell them re-man HD clutches for class 8 trucks... . everyone I've met is a professional and most of their crews have been in the business for a lot of years..... I've kicked myself in the A** many time for not waiting on a transmission and getting it from them... ...

 

[Cattletrkr]

After posting that last night, I went out and dumped a quart of Mobile manual transmission fluid in there. It's a straight 50 weight and NOT recommended for synchro'd transmissions. This morning things got a little worse and a couple times double clutching didn't even work. Then 3rd gear started giving me grief. About 30-40 miles into my route everything cleared up and now it shifts as perfectly as an NV5600 can get.

The Mobile fluid is made for regular "big rigs". I ran it in my '01 NV5600 for the last 30K before I sold it. Couldn't tell any difference in that one. Before I changed the fluid in my '04 the first time I did a little more digging and found out it was the wrong stuff. OOPS!!

I have 7qts of Penzoil Synchromesh waiting for me at the local Bumper to Bumper. Guess where I'm going in about 2 minutes?

BTW, I didn't make an *** of myself and call the transmission shop. Kinda glad I waited on that one.

One more thing. When I picked up the trans, the guy there said that with fastcoolers he'd put 7-8 quarts in the NV5600. "Fill er up. Don't worry about expansion or anything" Before adding the Mobile, I only had 5. 5qts of Amsoil in there, that was all I had available at the time. That brought it up to 0. 5 qt "overfull".

I ran Amsoil in my original trans for well over 100K, but I cancelled my order this morning. Looks like it's factory stuff for this one.

 

[steved]

I was going to ask if they installed the correct fluid... I know that has happened on more than one occasion...



steved

 

[steved]

OH, and I have nine quarts of fluid in mine with the fast coolers...

steved

 

[Cattletrkr]

How the #%@^ did you get nine quarts in there?? I just put seven in mine and it's right up to the fill/dipstick hole in the fastcooler. Did you go thru the top cover bolt? Shift tower?

I think factory spec is 9. 5 PINTS...

 

[steved]

How the #%@^ did you get nine quarts in there?? I just put seven in mine and it's right up to the fill/dipstick hole in the fastcooler. Did you go thru the top cover bolt? Shift tower?



I think factory spec is 9. 5 PINTS...

Through the fill hole in the Fast Coolers...



steved

 

[rbattelle]

I have fastcoolers, but run the fluid to the same level as the factory fill plug (which will be slightly overfull). I don't like the idea of getting the fluid level higher than the stock position.

I have nightmares about churning oil. As it is, the stuff churns in there like all get-out (have the clear cover on one fastcooler).

Glad to hear things have cleared up, Cattletrkr. How can Mobil MTF not be recommended for synchros? Don't big rig transmissions have synchros?

Ryan

 

[Cattletrkr]

Ryan, think of what would happen when you let the clutch out if you were to get an 80,000lb truck into gear with engine speed and ground speed not matched up . Car... . nage. As far as I know, no synchros. The Mobile fluid is much much much thicker at ambient temp.

Steve, last time I changed oil in my old transmission I turned the drivers side fastcooler around so the fill hole is on the low side. Much easier access that way. I guess there's 2qts difference there.

 

[steved]

I have seen increased temps running overfilled, but that happens even running over by 0. 5 quarts...

I have ran redline MTL for over 50 miles home from work, and literally jumped under the truck and popped the fill plug to see what drained out... never any hint of entrained air.

And while it sounds bad, that churning is also how the NV5600 lubricates itself... look at that big main gear in there through the PTO cover... its not like it doesn't ride in oil... just another way to look at it.

steved

 

[steved]

Oh, and my NV5600 with the Fast Coolers and filled to the "normal" level is just shy of 7 quarts. The extra two quarts (with the Fast Coolers) should be very similar to those running a full quart over without Fast Coolers.

And my fill plug is to the outside, at the lower point... I got all but an ounce shy of 9 quarts in there...

steved

 

[Cattletrkr]

I have extra/stiffer springs so I've got a really nice rake goin' on. That must be it. :-laf

When the dealer did the transmission swap they put in 5 qts and said that was to factory level, just shy of the side hole.

I'm not sure why we're seeing that much variation.

 

[steved]

I have extra/stiffer springs so I've got a really nice rake goin' on. That must be it. :-laf



When the dealer did the transmission swap they put in 5 qts and said that was to factory level, just shy of the side hole.



I'm not sure why we're seeing that much variation.

My springs are well worn, and very flat at this point... the only rake I get is with air in the bags...



But I'm not sure why... I have the "fill" cooler on the passenger side... and like I said, we filled it within an ounce of 9 quarts...



I do not have an explaination, but I could get 5 quarts in when stock, almost 7 to normal fill with the FCs, and 9 to the fill hole in the FCs.





Maybe they left some parts out of mine when it was built??? :-laf



steved

 

[Gary - K7GLD]

DUNNO - I had to really work at getting a full 4 quarts in mine when stock, and THAT was with parking on a slope to get the fill plug a bit higher. Now, with 1 fastcooler and the filter on the other side with it's larger capacity, I put in a bit over 6 quarts, and well above the OEM fill plug...

 

[steved]

Are you guys removing the PTO covers and swabbing out the fluid laying in the bottom of the trans?? That's a good 0. 5 quarts right there...

I pull my covers off at every OCI.

steved

 

[Gary - K7GLD]

Are you guys removing the PTO covers and swabbing out the fluid laying in the bottom of the trans?? That's a good 0. 5 quarts right there...



I pull my covers off at every OCI.



steved

I pulled mine off for the last upgrade - fastcooler and filter - but hadn't previously. Looked like perhaps a cupful of lube in the bottom, VERY hard to get in and thoroughly clean, but did my best. Took out the magnet pad, it and the bottom sump was LOTS dirtier than I would have imagined by simply draining and visually inspecting the drained lube. Most of what was there appeared to be non-metallic fine flour-like debris - perhaps syncro facing material? I have heard from sources the syncros are brass - others say either paper or some form of Kevlar. Never seen one apart, so dunno...



At any rate, in spite of miles, usage, and a couple of "alternate lube" mistakes, mine is shifting better today than when new - it'll never be a drag racer, but sure works great for RV towing!

 

[Cattletrkr]

The last time I pulled the cooler off is when I found those wonderful broken pieces that started this whole mess. They're not coming off ever again. Now I've gotta go look and see if the PTO covers are on the same level side to side.

This morning the truck didn't like 3rd or 4th. Once it warmed up everything was fine again. I'm thinking I could have left the Amsoil/Mobil combo in there. Oh well, now I have the "right" stuff.

 

[Cattletrkr]

Are you guys removing the PTO covers and swabbing out the fluid laying in the bottom of the trans?? That's a good 0. 5 quarts right there...

I pull my covers off at every OCI.

steved

Initial fill for this trans was after a fresh rebuild. I didn't pull the covers but I would assume it was empty. Rebuilder guy did say they fill them and dyno them, but I doubt they leave any lube in there. 5qts took it to factory level.