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

[Wyomingcowboy]

Hey guys, I have a problem with my 3rd gear grinding. The other day I was forced to drive with my only partially healed broken pelvis. I can push the clutch in with minimal pain but thought I would just speed shift after I got rolling in 2nd. Things were going well for the fist couple dozen shifts. Going up was no problem in any gear (shift about 2200 rpm) and had a little bit of grinding on the way back down. (tried to shift about 1750 rpm) Anyway, I started getting a grinding going into third. Today I drove some more and used the clutch for every shift but I still have the grinding. There is no way to "smooth" it into that gear no matter if I'm going up or coming back down and even if I double clutched.



What did I screw up and how bad is it gonna be? The transmission NEVER ground when going into any gear before. I did speed shift sometimes but not very often and I never had a grind. I would just apply constant steady pressure at 2200 rpm and it slipped right in.

Thanks guys

 

[blacksheepdiesel]

How many miles on truck? How many miles on transmission? How many miles on transmission fluid?

Godspeed,
Trent

 

[Wyomingcowboy]

108k on truck, transmission, possibly even fluid. I bought it with about 89k on it and I have not changed it. I know it's been horrible to do that but like I said, I have had 0 problems until now.

 

[blacksheepdiesel]

I would start with changing the fluid. Royal Purple is what I like and 11 quarts dumped in the shifter opening should do the trick. I know, I know, 11 qts is way over the spec but it helps lubricate the rear main bearing.

Godspeed,
Trent

 

[Wyomingcowboy]

how messy is that? Is it easy to remove the boot and stuff on top? (that is where you are talking about, right?)



also, what viscosity of royal purple?



thanks, Nate

 

[Wyomingcowboy]

Is it possible to have broken a synchro to the 3rd gear? Would it even go in at all without one? I had my mom drive it today with me and my broken pelvis riding shotgun and had the same grinding EVERY time except for once while she was going down a hill at a slow speed.

 

[blacksheepdiesel]

Nate,

Royal Purple Synchromesh - no separate grades IIRC. O'Reilly's carries it, should stock it.

Console and boot just takes removing a few screws, a few bolts, then the shifter pulls up and out - be careful, some fluid could possibly drip off! Piece of cake!

It is possible to break synchro's but I doubt that is what happened. A fluid change can make a world of difference!

Warning!: putting in 11 qts may allow some fluid to come out the rear main seal when going up and down hills (or in your case, mountains!) and be thrown over on the exhaust hence creating a new aroma. After a while the level will get to the point where that won't happen anymore. Nothing to be afraid of. My rear seal has not continued to leak and it has 90,000 miles on it and I started out with 12 qts of fluid. At eleven you may be fine to start with. If I feel so motivated tomorrow I will pull the shifter out of mine and measure the fluid depth in inches and report back.

Godspeed,
Trent

 

[Wyomingcowboy]

Awesome Trent. I just use the regular drain plug on the transmission I am assuming?

I will get started on it asap. !

 

[blacksheepdiesel]

The drain plug is the bottom bolt on the PTO cover.

Godspeed,
Trent

 

[CumminsPower98]

I wouldn't put anywhere near 11 qts in mine!! I have run 1 qt over full some but wouldn't go more then that. At 11 qts you will be causing a lot of drag and probably a lot more heat as most of the gears will be submerged at this level. 11 qts is 6 qts overfull. I have put 300k on my '01 6-speed (upgrade) at normal levels with plenty towing on hills and haven't had a problem.



As for your problem, yes I would start out by changing the fluid and go from there. You really should pull the side cover so you can clean the magnet and inspect for any debris. You can also stick a suction gun in there to get more of the oil out or mop it out with paper towels if you don't have a suction device. I installed a drain plug at the low point in mine to make this easier.

 

[Wyomingcowboy]

Any others want to chime in? I found an older thread talking about adding a mopar limited slip additive too with great results. I have also read about people burning up the rear main bearing due to lack of fluid.

 

[Matt42]

For what it's worth, I had this problem in a non-Dodge non-truck a long, long time ago. I had done something silly that caused some carbon buildup on a synchro ring and made it stick, causing a clash (also known as grinding) between some specific gear. An old time mechanic told me to try this:

Drain the old oil.
Add about 2 or 3 ounces of CD2 engine oil detergent.
Refill transmission with the correct oil.
Drive it normally for about a week.
The grind should go away.
Drain and refill again with the best oil available.

At 108,000 miles a trans oil change is way overdue. I also like Royal Purple. An oil change may solve the problem. Then and only then, I'd try the CD2 fix. That's unless it was my truck And I had done the same silly thing. I would never, ever add the CD2 to old, dirty oil.

 

[wilsonsh]

Yep just change the oil first...

Yep, changing the oil is the best place to start. Use the Royal Purple or whatever other kind of oil that is SPECIFIC to the NV5600(6 speed). NOT for the NV4500(5 speed)! I've read the posts on the LSD additive and thought there were mixed results but it didn't seem like it hurt the transmission. The synchros are clutch-pack style similar to a LSD so the additive allows the synchro to spin easier. Personally, I use Amsoil MTF but that's all I've ever used and I had to order it. I had the 3rd gear grind and it did go away when I changed the oil but who knows if another oil would have done the same thing.



I didn't see anyone else mention it but remember it's not a transmission that likes to be shifted without using the clutch. These have yellow(soft) metals on the synchronizers, unlike in over-the-road tractors, that will wear out quickly if they are not given relief from the cluch disengaging the motor. I ruined an NV4500 by not using the clutch. And NV5600s are getting very difficult to find parts for since NV is no longer around.



I think you'll be fine once you change the oil.

 

[blacksheepdiesel]

wilson,

You are correct that New Venture is no longer in business. Since that time Blumenthal's in Oklahoma City has worked to make the 5600 parts available. I was at Blumenthal's last year when the first shipment of new parts came in from Italy. Blumenthal is Chrysler's source for the reman 5600's.

Godspeed,
Trent

 

[wilsonsh]

Right on! You say you were at Blumenthal, are you a transmission tech or were you just visiting?

 

[Wyomingcowboy]

Thanks much guys. I think I am gonna do what blacksheep suggests and also add the LSD additive. That is if I ever get out of the hospital. I had a werck awhile ago and was healing but some new complications have arised so im back in. I'll do it asap and let you all know the results. I've got a move comin up in about a month and will be doing lots of trailer pulling. I should be ok with the overfill and trailer combo right away shouldnt i? or shoud i drive it around alot and make sure all the extra leaks out?

 

[blacksheepdiesel]

wilson,

I broke three teeth off of 6th gear between Tulsa and OKC, limped into OKC and found Blumenthal's on the internet. Was having a reman installed when I saw the shipment come in.

Godspeed,
Trent

 

[Matt42]

Yep, changing the oil is the best place to start. Use the Royal Purple or whatever other kind of oil that is SPECIFIC to the NV5600(6 speed). NOT for the NV4500(5 speed)! I've read the posts on the LSD additive and thought there were mixed results but it didn't seem like it hurt the transmission. The synchros are clutch-pack style similar to a LSD so the additive allows the synchro to spin easier. Personally, I use Amsoil MTF but that's all I've ever used and I had to order it. I had the 3rd gear grind and it did go away when I changed the oil but who knows if another oil would have done the same thing.



I didn't see anyone else mention it but remember it's not a transmission that likes to be shifted without using the clutch. These have yellow(soft) metals on the synchronizers, unlike in over-the-road tractors, that will wear out quickly if they are not given relief from the cluch disengaging the motor. I ruined an NV4500 by not using the clutch. And NV5600s are getting very difficult to find parts for since NV is no longer around.



I think you'll be fine once you change the oil.

Would the LSD additive be positive or negative in an NV 4500?

 

[wilsonsh]

dunno

Probably no effect or negative depending on the amount. 4500s do not have the clutchpack style synchros of the 5600s. The additive seems to allow the synchro to engage more smoothly.



I say no effect because there really is nothing that has slipping-style engagement in a 4500.



I say negative because it could thin the sheen of oil on the gear face/synchronizer ring if you add too much but this would also be the case in the 5600. That's why people are only adding maybe 4 oz to 5600s.



If you are having problems grinding gears in the 4500, you'll get the most benefit from changing the oil... possibly back to mineral oil if you have sythetic.



Also, make sure you are fully engaging the clutch when you change gears.

 

[wilsonsh]

wilson,



I broke three teeth off of 6th gear between Tulsa and OKC, limped into OKC and found Blumenthal's on the internet. Was having a reman installed when I saw the shipment come in.



Godspeed,

Trent

Man, that's tough. I bet it's nice knowing you had your transmission done by the best!!