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NV4500 5th gear

O

OrionThade

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Location
Orem, Utah
OK transmission gurus out there ...

My truck lost 5th today. I didn't hear or feel anything break, snap or make any unusual noises. I was getting on the freeway and shifted from 4th to 5th and it wasn't there. 1st through 4th work just fine.

I am not knowledgeable at all about transmissions, other than how they function. I've never pulled one apart.

So I know that the Dodge transmission has the issue with 5th gear where the retaining nut can work its way loose and the gear will slide back on the shaft. My understanding has been that the GM transmissions aren't prone to this problem.

Does anyone have experience with this? Can I investigate this issue with the transmission still in the truck, or do I need to pull it? I know the case is leaking so my thought is to pull it for no other reason than to crack the housing apart, clean it and then put it back together.

Like I said, I've never messed with transmissions before. Other than this, the only issue I have is an occasional problem with it shifting into 2nd, either while the truck is not moving or if I start in 1st. I suspect maybe the syncros are missing there.

Anyways, help would be appreciated.
 
I think 5th gear nut and gear backed of,it happens on GM NV 4500 as wel.
You have to pull the T-case and the Tranny to t-case adaptor from the tranny to access the fifth gear.
 
red said:
much less common on the gm nv4500 but still possible
Click to expand...

What he said. The GM's were used behind V-8's which has a smoother power output and is less prone to vibrate and back teh 5th gear nut off whereas the CUMMINS has more power per engine combustion event and a more pulsier type power output that vibrates and work them loose. I would just pull the rear housing off if it was mine, clean it off good with brake cleaner, use the red super strength loctite taht DODGE has, along with the split nut, and put it back together like the DODGE TSB says and call it a day. Shouldn't take you more than 3 hours, and less than $50 for the parts from DODGE last I checked.
 
Cool. Thanks for the feedback, gents.

I'm in NC on business for the week. Will take a crack at it next week when I get home. I'll take some pics and post a write up in case anyone else needs to do it.
 
Someone I talked to felt that accelerating, then letting off and decellerating (rocking the gear) had a little to do with it. IDK, it seems to have a bit of merit.


On a side note, any GM I have heard about with a spun 5th is usually the diesel. even though it is a V8, it is still a rattly diesel.


I got a 95 C3500HD bucket truck with spun 5th, so like said, not as common, but still happens.

anyways, like said, if you want to get it going quick, just pull t-case and t-case adapter tailhousing. while you are in there, make sure you have the harmonic damper. if you want to fix the 2nd gear shift, pulling the whole thing will be necessary.


good luck!
 
OK, update:

I have been tackling this for the past few days. Ran into a couple of hiccups, namely two of the 12 point bolts on the tail housing stripped off on me (even using a 12-point socket) so I had to grind them off.

The issue was not, in fact, due to the 5th gear issue but rather what appears to be a completely missing counter shaft snap ring. It looks like it has been missing or off the shaft for some time as there is some wear marks on the inside of the housing. My transmission was making a bit of noise when in fifth that I wasn't sure about but now thing it might have been this.

Need to call a couple of transmission shops in the morning to see if they have a snap ring.

My tranny has been leaking gold for as long as I've owned it, so I'm taking the opportunity to pull off the side covers and re-seal them. Obviously I'll be-applying RTV around the tail housing.

I snapped a few pics, but not as many as I was planning. When I get into "work mode" I tend to just work away and lose track of any other secondary task. I'll see about posting them when the job is finished.
 
IIRC, new venture did NOT want RTV used around the tailshaft housing, but rather anerobic sealant. dont quote me on it, but check before you do it. RTV on the PTO covers wont affect a darn thin, so go ahead on that.

did yours end up having the damper?

Blumenthals out of Oklahoma is a good place to get parts. IIRC, tanman2006 has gotten parts from there, and doesnt recommend the other outfit, Quad4x4, except for the manuals to rebuild it.

good luck on fixing it!
 
Good to know about the anaerobic adamant, GM Guy. There are a couple of tranny shops locally have worked on the 4500. Gonna make some calls in the AM. I'd like to get this fixed tomorrow.

In other news, I found the pieces of the broken snap ring. Gonna run some solvent through the bottom of the case to make sure I get all of the metal fragments out.

Question: will brakekleen harm the synchros? I wouldn't intentionally spray, but i want to make sure.

Sent from my PG86100 using Tapatalk 2
 
Anerobic sealer ONLY on the main case components for the NV4500. The reasoning for this is that RTV will only squeeze out to about 3-5 thousands of an inch whereas anerobic is designed to squeeze out to less than a thousandth of an inch before hardening(it will only harden in the absence of air undewr pressure). This helps the 2 pieces to hold togetehr as one unit with no where to flex, as well as less variance in the tolerances as teh anerobic will be so much thinner. As for brakekleen hurting the synchros, don't worry about that. But it WILL affect teh ability of the sealer to adhere, so make sure it is completely dry before applying sealer.
 
Thanks, Ferm.

I always rub down mating surfaces with acetone before applying any kind of sealant. I started doing that after I thought I had cleaned a surface well enough, but itbstill leaked.

Sent from my PG86100 using Tapatalk 2
 
OrionThade said:
Thanks, Ferm.

I always rub down mating surfaces with acetone before applying any kind of sealant. I started doing that after I thought I had cleaned a surface well enough, but itbstill leaked.

Sent from my PG86100 using Tapatalk 2
Click to expand...

Acetone wil lalso cause RTV and anerobic sealers not to bond if you don't let them dry long enough for all residue to dissipate.
 
OK.

Called around to a bunch of transmissions shops and both GM and Chrysler dealers.

Found a large transmissions and driveline shop that rebuilds a LOT of NV4500's. After talking to the shop closest to me, found the snap ring at the shop in SLC. So, had to make a 65 mile round-trip to get a $1.11 part. Such as it is.

I found out some interesting information.

My transmission does not have the dampener. The rebuild tech at both locations confirmed that the dampener was not installed in the early years. The tech manual said 97+. I was going to order one, but they're close to $200 and it would have taken a week to get. I don't have that kind of time.

I asked about anaerobic vs silicon sealant. Both shops use silicon on every transmission. The one technician said that he's never had a tranny come back leaking or having other issues as a result of using silicon over anaerobic.

I asked about torque specs for the for tailshaft housing. The local technician said he just uses his impact wrench, he doesn't use a torque wrench. I found that interesting. He also always throws out the pieces of crap 12 point stock bolts and puts 6 points bolts on. I'm OK with that.

Finally, I asked them if they carry the liquid gold. They don't. They were very insistent that the ONLY put 2 quarts each of Redline MT-90 and Redline MTL in their rebuilds. Both are GL-4. MT-90 is 75W90 and the MTL is 70W80. I hounded the tech several times about this and he was quite insistent that they've not seen any issues with using this over the Syntorque. I took him at his word and bought it. Price difference was $10 per quart. I prefer $16 a quart over $26 a quart.

Today I'm going to get the snap ring installed, the transmission case cleaned out and hopefully get the PTO covers and tailshaft housing reinstalled. Tomorrow, I'm hoping to get it buttoned all the way back up.
 
Truck is back on the road.

So far feels good. Shifts feel smoother and easier with the Redline oil. And so far no leaking oil, which is good.

All in all, it wasn't too difficult. The hardest part was mating the transfer case to the transmission. It's not light, I'd guesstimate close to 100# but I was able to lift it in place unassisted.

I am certainly less intimidated by the idea of remove the transmission today than I was before I started the task. All i would have needed to do at that point is remove the shifter and the transmission to bellhousing bolts and slide the transmission back.
 
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