Engine/Transmission (1998.5 - 2002) NV5600 & Synchro's

[Silver_Ram]

A friend of mine at a local diesel repair shop called his trans rebuilder for me. The trans rebuilder said the synchros in NV5600 are not brass, but more like mini clutch packs. The trans rebuilder said that's why my NV5600 started shifting better after the limited slip fluid was added.



I have only driven the truck twice in the last week & she still shifts very well. Still waiting on Amsoil to see if they have checked on the compatibility of their own limited slip additive with their synchromesh. I don't drive my truck as much as I used to, so it will take some time to get build up mileage.

 

[Tomeygun]

That is what I was thinking about because I have a NV4500 that is not quite right going 4 to 3 ever since I put this one in.



Kent

Copy that, I have AMSOIL in my NV4500... It helped make it better then when it had stock stuff in it. BUT I still get a little grinding in cool morning between 1-2 shift (unless I double clutch it)



3-4 shift is the same, It can be a booger unless I hold rpm up between shifts...



I'll ask my tech at Dodge

 

[kscheffler]

Any updates on compatability issues?

 

[Silver_Ram]

I sent another email to Amsoil to hear, to see where that's going.



If someone else wants to ask around about the additive in the transmission, it could help with the uncharted territory.

 

[MrDiesel]

I'm going to try it... just wondered if any one had any up-dates. Also what oil should I use? I did a search to find out what people are using but I'm not comming up w/what I'm looking for (probably user error!). Thanks!

 

[Silver_Ram]

MrDiesel,



I have tried almost every oil available stock, Pennzoil, Royal Purple & Amsoil Synchromesh. I like the Amsoil best so far, the stock fluid would be my 2nd choice.

 

[MrDiesel]

There is an Amsoil dealer down the road from me, what should I ask for? I was leaning that way already, thanks!

 

[Silver_Ram]

MTF - Synchromesh Transmission Fluid, make sure it's the 5W-30.



If you plan on going synthetic in the rest of your truck, I would join as a Preferred Customer. It allows you to buy at dealer pricing without being a dealer.

 

[maxburk]

Silver Ram. Thanks for doing all the foot work on this problem. I have a 2001 with a 5600 and have the same problem. Changed to Amsoil and it made the problem much better.

I have 100k + on the transmission. Think I will take a deep breath and put the additive in since it seems to work and should not hurt anything.

 

[Midnite]

Well, it sounds like the answer to whether the LSD additive would be worthwhile to add to the NV4500 is a definite no, from what I'm reading here. The only reason it works on the NV5600 is because of the fiber (?) synchros, and since the NV4500 synchros are brass, there's no point to it.



Mike

 

[Fogie]

Somebody has something mixed up here. The NV4500 has the fiber synchros. Never seen the inside of the NV5600, but I have heard than some guys are changing to the brass synchros to improve the shifting. Shifts slower with the brass, but smoother. Gear oil wise the the NV4500 uses synthetic GL-4, and the NV5600 uses the GL-5. The claim is the GL-5 will destroy the fiber synchros in the NV4500.

 

[V-Metalworx]

I've got my NV5600 tore apart all over my bench it does have fiber sycro's they look like a clutch disk out of a motorcycle pack one transmission guy said not to run brass sycro's because they wer'nt compatible with the transmission and fluid he said run factory fiber and keep your transmission oil serviced often don't know for sure thats his op.

 

[steved]

I've got my NV5600 tore apart all over my bench it does have fiber sycro's they look like a clutch disk out of a motorcycle pack one transmission guy said not to run brass sycro's because they wer'nt compatible with the transmission and fluid he said run factory fiber and keep your transmission oil serviced often don't know for sure thats his op.

What year transmission??



steved

 

[V-Metalworx]

mine is the early 1. 25 inputshaft its in a 2000 wish I had a 01 or 2 to tear apart right beside it sense no one can tell me what the difference between the gears and sycros they just say their differnt wish somone had a broke one Icould buy cheep to find out

 

[steved]

mine is the early 1. 25 inputshaft its in a 2000 wish I had a 01 or 2 to tear apart right beside it sense no one can tell me what the difference between the gears and sycros they just say their differnt wish somone had a broke one Icould buy cheep to find out

I was hoping it would be a later transmission... thinking I might try this trick!



steved

 

[Silver_Ram]

Steved,



I have had two different trans rebuilders tell me that the NV5600 trans has mini clutch packs instead of brass synchros. I do know the NV4500 oil is different than the oil for the NV5600, so they're probably not the same.



I will double check again with them.

 

[pwr2tow]

This is a very good topic and would like periodic updates. How are things going? Anyone else useing this or have been for a long period of time?



Thanks

 

[pwr2tow]

any updates?

 

[Midnite]

Somebody has something mixed up here. The NV4500 has the fiber synchros. Never seen the inside of the NV5600, but I have heard than some guys are changing to the brass synchros to improve the shifting. Shifts slower with the brass, but smoother. Gear oil wise the the NV4500 uses synthetic GL-4, and the NV5600 uses the GL-5. The claim is the GL-5 will destroy the fiber synchros in the NV4500.

Regarding GL-5 in the NV4500, I've actually read quite a bit that the problem is that the GL-5 isn't compatible with the brass synchros (ie, the 4500 doens't have fiber synchros). I believe that info came from Standard Transmission and Gear. I've never been into an NV4500, so I have no first-hand knowledge.



Mike

 

[Silver_Ram]

I finally got a chance to talk to the Tech @ the dealership about putting the additive in my trans. He tried it for the first time about 2. 5 years ago, because he was getting tired of Dodge not wanting to cover anything. He said he has put the additive in the NV5600, NV4500, and any other Dodge - Jeep product having manual trans shifting problems with good sucess.



I asked him if I needed to add it every time. He said he hasn't had a vehicle come back that needed it a second time.



I talked to my friend at Six States & he told me when they repair a NV5600 it goes filled with synthetic 75W-90 gear oil. He said they weren't getting any negative feedback for hard shifting when it's cold.



I drove the truck around town today & it's still shifting great.



Antone else tried it yet??