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

[Silver_Ram]

I took my truck into the dealer last week, because I was having a hard time down shifting 5-4-3 gears & in general it just sucked. I was grinding the downshifts 60% of the time. I am tired of changing the trans oil every 5,000 miles lately.



The tech tried telling me it was fine, the type of transmission made it shift that way. When I told him the trans didn't shift like this for the first 50,000 miles. He took his boss for a ride & they tried to tell me nothing was wrong. I then told them the mechanic that changed my front gears out a month ago, had also said the sychros were going out. The tech said next step would be to pull it apart to take a look.



The next day, I get a call from the service manager saying my truck was ready. The service manager asked me "when you change the trans oil, do you put the additive in the oil". When I asked what additive?, he told me there was an additive specifically for the trans. I asked for the part number. He was going to check into it for me...



I pick up the truck & immediately notice the more I drive it, the more the transmission shifts loosen up, & don't have the bound up feeling it previously had. It became a lot easier to put in gear from an idle, upshifts didn't have that two step click, & I could down shift 5-4-3 without grinding the gears.



I couldn't reach the Service Manager, so I called his parts department & they told there wasn't an additive for the transmission. I told them the above story. Needless to say, the Service Manager finally called back & told me the additive the tech had put in the trans was actually the Mopar Limited Slip Differential gear oil additive.



It has approximately a 1/2 bottle of the additive in the trans right know, I bought some more & I'm gonna add one full bottle.



After 600 miles, the trans has smoothed out quite a bit,almost car like smooth. I'm gonna see if I can improve it some more. I will post again when I see how well a little more additive helps... .

 

[kscheffler]

Have never heard of this but makes some sense as long as the LS additive is compatable with the metalurgy in the transmission. Let us know how it turns out. Are you using the Dodge OEM oil for the transmission?

 

[Fogie]

Think I would be finding another dealer to take a look at. Maybe even file a complaint about the additive. Give Dad at Quad 4X4 a call and ask him about it.

 

[Silver_Ram]

I will have to find out whether or not the additive is compatible with the transmission.



I added a full bottle to the Amsoil Synchromesh trans fluid & it shifts smoother with every shift. It shifts more like a car now than a truck.

 

[Silver_Ram]

The E-mail I sent to Dodge

Here is a copy of the e-mail I sent to Dodge, we'll see if I get a response.



I had my truck into West Valley Dodge for hard shifting transmission problems. The technician initially said it shifted fine. I told them I was having downshifting problems & that changing the gear oil only helps for a short time. The transmission oil was not low & the technician said I don't have a clutch problem.



I know the NV5600 6 speed transmission has a specific oil, (not gear oil) for reasons set in place by New Venture Gear.



My question is: Are the actions of the technician adding the Mopar Limited Slip Axle Lubricant Additive a proper repair? If so, has a TSB for hard shifting been issued?, or will Dodge look into this as a viable repair? I have spoken with 2 other dealers & they haven't heard of adding the Mopar limited Slip Axle Lubricant Additive to the transmission.



I can attest that it worked, but I don't know if the Mopar Limited Slip Axle Lubricant Additive is compatible with the NV5600 internal parts. If the transmission oil was normal gear oil, I would not have any questions. I don't want to find out that the Mopar Limited Slip Axle Lubricant Additive is going to ruin the internal transmission parts.



I tried to contact New Venture Gear, but they were sold to Magna International out of Canada. I couldn't find a New Venture Gear contact on The Magna International website.



Your help in this matter will be greatly appreciated,



Michael Fenn

 

[CFAR]

I've used both the penzoil and the dealer stuff. I haven't had any problems, but it don't shift like a car either. Keep us posted, maybe an oil analysis is in order?

 

[Froadin]

If the answer is that easy, I will be all over it. But I seem to doubt it.

Seems like the additives that are specific to our oil might be comparable to what is found in the limited slip stuff as well. Or at least something that gives us a similar effect.

 

[Silver_Ram]

The shifts have improved alot. It shifts better than it ever has, & It goes into reverse alot better. The bound up feel of the transmission is gone.



The truck has 77,000 miles & I had noticed the shifts were getting worse.

I hope this is an okay fix. I also sent an e-mail to Amsoil to get there opinion on mixing the additive with their synchromesh. If not, I'll ask if their Amsoil Slip Lock additive will be OK.

 

[Silver_Ram]

Still Shifting Great

The trans is still shifting great... Dodge Customer Service cannot provide Technical advice (imagine that).



I talked with a buddy at Six States & in his opinion the additive won't hurt anything in the trans. He has rebuilt several NV5600's.



Amsoil says there is nothing wrong with mixing the Mopar additive with their Synchromesh. The Amsoil Rep. said he is going to see about testing Synchromesh with their limited slip additive (Slip Lock).



I'm gonna keep trying it, & see what happens. I was have the synchros replaced, maybe I can get a little more mileage out of them. .

 

[kscheffler]

Silver Ram: How much did you add and do you have fast coolers?

 

[Gary - K7GLD]

Adding LSD friction modifier to the 5600 because of poor shifting related to syncro function would seem to be exactly the wrong "cure"!



The FM is usually added to differentials because there's not *enough* LSD clutch slippage, resulting in differential "chatter" in turns or low traction situations. In that case, the FM is added to allow *more* slippage and reduced chatter.



In the case of poor transmission shifting because of insufficient syncro operation, you would think making the lube more slippery would just create worse syncro operation due to increased slippage with accompanying reduced syncro function.

 

[nps]

Adding LSD friction modifier to the 5600 because of poor shifting related to syncro function would seem to be exactly the wrong "cure"!

So you saying Silver Ram is full of BS, or do you think he is lying?

 

[Bob Cochran]

Oh please lets not start. Gary said "it would seem to be exactly the wrong cure". I just cannot get that to say Silver Ram is full of BS or lying. It is an opinion and we all have them right? Sometimes opinions are helpful and if we stop giving them probably 50% of posts would be gone and a lot of useful help. No need to get this started again, please. Okay of the box again.

 

[Silver_Ram]

kscheffler: The Service Manager said the tech had some left over, I think it was half a bottle. I added a full bottle, the bottles are probably 2 or 3 ounces. So the total is around a bottle and a half.



Well whether it seems it is the wrong cure, it worked like a charm. My buddy @ Six States had noticed the shifting problem when he did some gear work a month or so ago. He's as dumbfounded about it as I am. He said he would have never thought of putting in the additive.



For any disbelievers, drive to Salt Lake, and we'll go for a spin. I'm not a guru by any means (thus my buddy at Six States). If someone wants to stop by, the can have an oil sample. Just bring some Amsoil Synchromesh, I have 3 more bottles of the Mopar additive on the tool box.



I not well versed about synchros, other than they're supposed to make the trans operation easier but the slippery stuff made a big difference for ME. If someone else out there is having shifting trouble, spend the $4. 93 at the local dealer, put it in & drive. I can't gaurantee the results, but we'll have a second opinion.



IF YOU HAVE ANY DOUBTS, DON'T DO IT, THE CHOICE IS YOURS... . Maybe I just got lucky for the second time in my life... .

 

[kscheffler]

I have a transmission oil change coming up in another 7k miles I am going to add a bottle and give it a try before I drop the oil and get another opinion; maybe others should give it a try. .

 

[Midnite]

Not to hijack this thread, but does anyone know if the limited slip additive is compatible with the NV4500 internals? I realize they're different than those of the NV5600.



Mike

 

[Msilbernagel]

I have a transmission oil change coming up in another 7k miles I am going to add a bottle and give it a try before I drop the oil and get another opinion; maybe others should give it a try. .

I'd be concerned about compatibility with yellow metal. Not based upon knowledge of any facts at this point, at least with regard to the additive.



However, this was the reason for some failures of the NV5600 when folks used non-spec'd lube early on... the additive package somehow attacked the bronze synchro parts and fairly quickly caused the transmission to fail.



If there is a way to confirm this particular additive package won't harm/attack the metals (perhaps oil analysis), then if it 'works' I'd go for it myself.



Mine also has that tendency to be a little stiff when cold, especially going into third the first few times.



Mark

 

[FOXY005]

They used to use actual "Whale Oil" in the old Posi Rears to stop the Chatter and it was real slippery stuff when you got it on your fingers, it worked better IMHO than the synthetics they use today now if I could just get my hands on some of that I would love to add it to the transmission and see if it would smooth it out any.

I think everyone with a NV5600 has the same shift "notchyness" (is that a word) from what I have read, it will be interesting to see how the limited slip additive works out after some mileage is on the units with it in.

 

[NVR FNSH]

The dealer told me STAR recommended adding the limited slip additive to my 5600 after the trans was replaced and I still complained about the shifting. Initially, the mainshaft assy in my orig trans was replaced and then they replaced the entire trans. After adding the LSD additive my 5600 shifted like butter for a week or so.



Hohn has reported good results with Redline MTL and Lube Gard Gear Fluid Supplement additive http://turbodieselregister.com/forums/showthread.php?t=127766



How long has the LSD additative been in the transmission now?



Brian

 

[Kent Kuykendall]

Not to hijack this thread, but does anyone know if the limited slip additive is compatible with the NV4500 internals? I realize they're different than those of the NV5600.



Mike

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