Engine/Transmission (1994 - 1998) NV4500 3rd gear grinding

[Rowingfish87]

I have a 98 12v 4x4 with the NV4500 5spd. Recently, as I shift from 2-3, 3rd will grind really bad. If I baby it it will go in without grinding but I almost have to double-clutch to prevent the grind. None of the other gears have any problems as I have already fixed the notorious 5th gear with a revised nut. I am assuming that my 3rd gear synchro is going or gone and I was wondering if anyone had any insight on this problem.

Also does anyone have a tear-down manual for the NV4500 or know where I can get one on the cheap (aka free)? I will want to do this fix myself as I need to pull the trans to fix a leak and resurface my flywheel anyways. How involved of a job would it be to replace the 3rd gear synchro if it is in fact my problem?

3rd gear will hold just fine once I get it in, even while towing.

-Kyle.

 

[Draught]

nv4500 grinding

My transmission also grinds but it is going to 3rd have to shift in to it at 20 mph. What a pain,i found info on it at quad 4x4 web site they may have the info you need. I ordered a trans,from standard transmission will be putting it in on the 28th it came up graded with shafts and 5th gear.

 

[abranz]

My experience is that the fluid in it makes a heck of a difference. If you have anything other than the oe syntorq you might try changing the fluid before tearing it down. Tony

 

[TBartlett1]

The NV4500 in my 1990 started to grind slightly as the miles accumulated so I started double clutching to nurse it along. Currently 3rd syncro has long been gone and 4th is a bit weak but I've adapted as it progressively got worse and have gotten dam good at it. You just need to take an additional breath before you shift and match engine speed to get a good shift. I kinda enjoy the challenge!

It will be repaired when it exhibits terminal symptoms.



Tim

 

[SRadke]

pm me your email addy and I'll send you the manual. You have to pull the mainshaft to get to the 3rd gear syncro which requires new bearing on the mainshaft but for a relatively mechanical farm shop kinda guy it's no big deal.

-Scott

 

[David_VT]

Great thread, keep the info flowing!
Mine goes into 3rd real hard from both directions but always stays in gear once I get there. If I really concentrate on matching the speeds, I can get it but not that often.

 

[Matt42]

If the third gear synchro is about worn out from use and mileage, this idea won't work. If it grinds because the wrong fluid was used and the synchro ring metal eroded, this idea won't work. If it grinds because the fluid got low from a leak and a little carbon or gunk built up on the synchro ring due to a hot spot, it should work.



Buy a small bottle of CD-2 engine oil detergent additive. Put about half of it into the transmission. Drive for several days to a week of normal driving where the transmission fully warms up. Do not go longer. As you drive, if it is going to work, the grinding will lessen as the carbon or gunk is removed.



At the end of the week or so, fully drain the transmission and refill with the correct fluid, e. g. , Syntorq. I have used this on other manual transmissions, but have never needed to do it on my NV-4500. Do not leave the CD-2 in too long because it can also start to erode the metal that the synchro rings are made of.

 

[Rowingfish87]

My experience is that the fluid in it makes a heck of a difference. If you have anything other than the oe syntorq you might try changing the fluid before tearing it down. Tony

just changed the trans fluid with fresh castrol syntorque from the dodge dealer (~$90 in fluid) when I fixed 5th gear about a month ago.

 

[Rowingfish87]

Great thread, keep the info flowing!

Mine goes into 3rd real hard from both directions but always stays in gear once I get there. If I really concentrate on matching the speeds, I can get it but not that often.

x2 keep it comin.

 

[Draught]

when i ordered my trans from standard transmission they recommended using amsoil MTG oil

 

[Rowingfish87]

when i ordered my trans from standard transmission they recommended using amsoil MTG oil

I've heard good things about that fluid but it really isn't any cheaper for me to have it shipped to me and it is to go to the local dodge dealer and buy the castrol syntorque.



any suggestions on where to get the parts I would need for this?

 

[Matt42]

just changed the trans fluid with fresh castrol syntorque from the dodge dealer (~$90 in fluid) when I fixed 5th gear about a month ago.

1. What fluid was in it before the 5th gear problem?

2. Do you know the transmission's history from new?

 

[Rowingfish87]

1. What fluid was in it before the 5th gear problem?

2. Do you know the transmission's history from new?

1. judging by the rest of the status of the truck when I purchased it it was probably the original castrol syntorque.



2. no. didnt grind when I bought it tho.

 

[DProehl]

I have repaired 3 NV4500's this past year all had 3rd gear syncro problems. All three trucks had pilot bearing issues that resulted in a drag on the input shaft causing the driver to have to push harder to get it into gear. This eventually wore the material off the 3rd gear syncro causing the grind issue. These transmissions have steel syncro rings with a friction material bonded on to it. I believe using the wrong non GL-4 oil will cause bonding issues with this material. All three trucks I replaced the pilot bearing with the Quad 4x4 ball bearing and machined the flywheels to except it. I have gone both ways with syncros, OEM bonded or the brass replacement type. I have not seen any longevity or shifting issues with either type. Minimum parts to order are: syncro set, mainshaft shim kit, counter shaft shim kit, input seal and if not upgraded a new style 5th gear nut. Good luck and have fun!