Engine/Transmission (1998.5 - 2002) 6-spd. 3rd gear grinding

[Silver_Ram]

I'm the one that initially posted about adding the LSD fluid. I am running Amsoil 75W90 trans fluid and 2 bottles of Amsoil LSD fluid. I am only running 1 quart past full & everything is still fine. Cold temps make the first 3 or 4 shifts hard, but after that it's good.



I have also done the 75W90 synthetic & the LSD fluid on 2 NV4500 trannies and it cured their problems as well. . The key here is the LSD fluid...

 

[blacksheepdiesel]

Silver Ram,

How many mile have you put on that concoction?

Godspeed,
Trent

 

[Gary - K7GLD]

I'm the one that initially posted about adding the LSD fluid. I am running Amsoil 75W90 trans fluid and 2 bottles of Amsoil LSD fluid. I am only running 1 quart past full & everything is still fine. Cold temps make the first 3 or 4 shifts hard, but after that it's good.



I have also done the 75W90 synthetic & the LSD fluid on 2 NV4500 trannies and it cured their problems as well. . The key here is the LSD fluid...

The lingering question in my mind about adding LSD fluid (friction modifier) is, it may make shifting better - but what about long term lubrication? I'd hate to fix one problem, only to create another...

 

[ROADWARRIOR]

My dealer put the LSD friction modifier in my NV4500 back in '99 and it hasn't caused any issues yet that I can tell. It was the only thing that helped my hard shifting. They tried this after replacing the top portion of the trans with no improvement. I put 2 bottles in every fluid change.



Dan

 

[MMeier]

Anybody ever deal with drivetrain.com? I bought a few parts form them awhile back for a NPtransfer case out of my old chevy diesel. They were real nice to deal with and their techs were very helpful.

Anyway, they are selling parts for the NV5600 and I was wondering if anybody knew if their parts were any good or not.



Thanks

Stay the F away from those crooked MF'ers!!!!!! those are the idiots that royally did me over on my 5600... read some of my previous posts on it, all they kept doing is blaming eveything else other then the trans they had apart NUMEROUS times... sell a shifter, "oh you need the special Mopar lube, oh your clutch is crap, blah blah blah!!! #@$%!

 

[Silver_Ram]

Trent,



I currently have approximately 8,000 to 10,000 miles on the fluid "concoction" in my transmission.



My buddy at the transmission shop told me that the synchros in the NV5600 & NV4500 are like mini clutch packs, kind of similar to limited slip clutches. Apparently thats why the LSD fluid works.



I tried everything fluid I could get my hands on, and none of them lasted more than a month. Added the LSD 1 bottle - improvement & then a 2nd bottle - works well for me. Try it if you like, if you're unsure - then don't.



There ten trucks running the concoction around here & everyone's happy.

 

[FLynes]

My dealer told me the same thing, but he only added one bottle of LSD fluid, after the rebuild. I did notice an improvement right away, but to me it felt like the effects went away after 10,000 miles or so. Maybe two bottles is the trick.

 

[Silver_Ram]

As far as I am concerned, it is a small price to pay compared to a rebuild.



Try another bottle & see what happens. Mine is still great.

 

[MMeier]

As far as I am concerned, it is a small price to pay compared to a rebuild.



Try another bottle & see what happens. Mine is still great.

How do you use your truck?

 

[Silver_Ram]

Its sits more now, because it isn't my daily driver. 65% is going for long rides, 35% is towing my 10,000 lb 5th wheel.

 

[Wyomingcowboy]

Another update: I finally was able to do some towing this week. I borrowed a nice Hart stock combo GN to move all my stuff to the arm pit. (aka Rock Springs) When I got down there I noticed I had quite a bit of transmission oil on the trailer. By quite a bit I'm not sure how much... . it wasn't dripping or anything and it doesn't take alot of oil to make a mess. Anyway, I didn't smell it burning as it was quite cold (high 50's) and rainy. I also am having very crappy shifting in addition to my 3/4 syncro being shot and am going to go back to OEM as soon as money allows. The pennzoil synchromesh doesn't appear to be working too well even with the 4 oz. LSD additive thrown in with the 11 qts. I might just have to replace that synchro and 3rd gear at the same time. I hate having to JAM it into 3rd while downshifting and having that terrible grind everytime.

When I go back to OEM fluid I will go with 10 qts. and see how that goes.



On the plus side I was able to set my cruise and had no problems on any hill with just my hypertech. The egt's got a tad high sometimes (1350 was the highest) but not too bad for having the restrictive stock exhaust I thought... . ? That's another thread I guess...

 

[Silver_Ram]

WyomingCowboy



Before you go back to the stock fluid - try synthetic 75w90 & the LSD fluid. I wouldn't suggest putting 10 quarts in, that seems a bit too much. If I remember right, the transmission has a breather on top. Rock Springs gets colder than Salt Lake, so you may have to go thinner when winter really hits. Last winter the first three shifts were stiff, but after that it was gravy.



I tried the synchromesh & it was probably the worst fluid I did try.



I have an extra quart in, the LSD fluid goes in after 4 quarts. I jack up the drivers side (front & rear) after the transmission is full & add the extra quart. I don't get any mess from the transmission. If it still grinds after that, I would say it's time to get some transmission work done.



If it gets to that point - I know a couple of shops that I have had good luck with here in Salt Lake City - which isn't to far from Rock Springs.

 

[Wyomingcowboy]

Wouldn't that be too thick even with the LSD additive?



What all parts am I wearing out by jamming it into gear while downshifting from 4th - 3rd? Besides a syncro, and a possible 3rd gear from nasty grinding, what other componants are wearing in there?

 

[EricBu12]

My rebuild man at Six states was telling me that to use 75W-90. . for the 5600

I told him I use the Amsoil MTF and said it was a little different formulation than gear oil but basically the same.

I did a Rebuild a while back and have the New Trans Coolers. I run the left side of the truck on truck ramps and then filled the fluid in the normal hole till it ran out... . about 1 quart over full. I don't think I would EVER put in 11 quarts. . maybe another quart or 2 more than now but like only 7 or 8 total. .

 

[Wyomingcowboy]

ya, i am beginning to think 11 is super duper overkill too. The underside is all oily from the extra leaking out. I will certainly add no more than I take out... when it comes time.

 

[Silver_Ram]

The Amsoil MTF (5W30) is good stuff, but I am using the Amsoil MTG (75W90).



It doesn't seem to thick at all during the summer. The cold times & first three shifts were stiff. In the cold it doesn't grind like it did before the LSD. Mine was a 4 to 3 downshift grinding. I figure with mine, the synchros are already worn, so I am trying to prolong pulling the transmission as long as I can. So far it's working.



I was told the grinding isn't the gears, but the grinding sound was the synchros not engaging or disengaging correctly.



Good Luck

 

[Wyomingcowboy]

Well if you have been following any of my posts you have seen that i am currently in the process of pulling my motor and either rebuilding it or replacing it. I thought that I might as well get at that transmission while I'm at it!



Anyone know of any rebuild kits for the 5600? I know I will need that one synchro for sure, maybe more parts too but I might as well replace seals/gaskets while I'm at it.

Also, how about a clutch? Mine was working fine before all of this but I suppose it won't hurt to do that while I have it all apart. I read alot of threads recommending it but, as always, money is an issue too.



Thanks again guys. TDR has saved me so much already. I appreciate it all!

 

[blacksheepdiesel]

WyBoy,

Call Blumenthal's in Oklahoma City, they will have everything you need for the 5600.

As for the clutch get a South Bend OFE, it will fit perfectly with what you use the truck for. Make sure whoever installs it torques the pressure plate to specs.

Godspeed,
Trent

 

[Wyomingcowboy]

I will be doing everything... . I even have some body work in mind while I'm at it!



What kinda prices am I looking at for the southbend?

 

[blacksheepdiesel]

$900ish I think

Godspeed,
Trent