Noisy NV4500

[rgunlock]

I recently swapped an NV4500 into my '78 K15. This NV4500 came from a donor truck and I had it rebuilt (supposedly) by a drivetrain shop 6 years or so ago. It's been stored since then. I've had other issues with this shop, so I am not ready to vouch for the thoroughness of the job done.

I am getting two distinct noises when I go into 5th gear OD. First is a fairly loud high pitched whine/drone. This noise definitely does not exist in 1st-4th. It seems to fade the longer I'm driving in 5th, but doesn't stop and certainly comes back after downshifting and then back to 5th.

The other is a metallic rattling noise while in 5th. This noise might exist in the other gears but is not nearly as noticeable as it is in 5th.

I've tried to search for this topic without a whole lot of success. One thing that comes up is bad driveline angles. I can't swear that mine are ideal yet, but the noise only exists in 5th and doesn't appear to matter whether RPMs are high or low while in that gear. The rattling noise doesn't seem to be affected by putting pressure on the shifter in any direction.

Granted, I've got gaping holes in my transmission hump that i haven't patched yet, and I was driving without carpet or boots to block the noise. I suspect the noises won't bother me too much once I've finished the flooring. The reason I'm posting this is to get you guys opinion on whether this sounds like anything I should be concerned about. Other than the noises the NV4500 seems to be performing just fine so far.

[rgunlock]

I'm not sure how to interpret the lack of response on this. Did I ask a stupid question and I should just take it to a drivetrain shop and let them diagnose the noise? Or maybe I posted on the wrong forum?

[mongocanfly]

What yr model nv do you have?...I know the early ones had issues...both of mine are the later yr models and were rebuilt and syncronizers upgraded when i got them...ive not had any issues so far....
It kinda sounds like you may have a bearing problem.....

[franken]

I have a 96 in the garage bit it and related parts haven't made it into the truck. I parted a sub w/ an NV swap that drove very well. I think it was a rebuilt (by the PO) early version but I sold it.
I'd seal things up, then think about it. Assuming you have a removable high hump, undercoat it?
As I recall if you have a low numerically rear gear, the 5th tends to be weak, shall we say. I'm pretty sure the sub had a 410 which was nice to drive.

[SunSoaked]

I doubt that driveline angles would cause tranny noise. 5th gear had an issue with the nut backing off, but it might have been particular to the Dodge versions. The way you describe it as " high pitched whine and metallic" are indicative of the bearing going south. A few years ago I had the exact same noises from my Nissan's 5 speed. 4th gear was silent, shift into OD and it got ugly. I took it to Ramco and they rebuilt it. Sure enough, bearings related to the shaft with OD were shot. If one bearing is bad, replace them all. The synthetic oil for the 4500 is CRITICAL!...and expensive!

[rgunlock]

Thanks for the replies.

Originally Posted by mongocanfly

What yr model nv do you have?...I know the early ones had issues...both of mine are the later yr models and were rebuilt and syncronizers upgraded when i got them...ive not had any issues so far....
It kinda sounds like you may have a bearing problem.....

I'm not sure what the year model is. I'm under the impression that it is a '96 or later. It came out of a '92 truck but I was told this is not the early GM NV4500. I've added a couple pictures if they tell you anything.

Originally Posted by franken

I have a 96 in the garage bit it and related parts haven't made it into the truck. I parted a sub w/ an NV swap that drove very well. I think it was a rebuilt (by the PO) early version but I sold it.
I'd seal things up, then think about it. Assuming you have a removable high hump, undercoat it?
As I recall if you have a low numerically rear gear, the 5th tends to be weak, shall we say. I'm pretty sure the sub had a 410 which was nice to drive.

I do have the removable high hump and it is undercoated. It is also insulated on the top, or will be once I finish patching it up. Yes, this truck originally had 3.08 gears but I have already swapped in 4.10s and other than being noisy in 5th the truck seems to be driving well.

Originally Posted by SunSoaked

I doubt that driveline angles would cause tranny noise. 5th gear had an issue with the nut backing off, but it might have been particular to the Dodge versions. The way you describe it as " high pitched whine and metallic" are indicative of the bearing going south. A few years ago I had the exact same noises from my Nissan's 5 speed. 4th gear was silent, shift into OD and it got ugly. I took it to Ramco and they rebuilt it. Sure enough, bearings related to the shaft with OD were shot. If one bearing is bad, replace them all. The synthetic oil for the 4500 is CRITICAL!...and expensive!

I've got the AA adapter kit which is supposed to address the problem with the nut backing off. I used Amsoil which specifically calls out that it works in NV4500 and I've read about a number of folks using it successfully.

Sounds like I've got 2 votes for bearing noise. I did have this transmission rebuilt but it is possible that the guy replaced seals and gaskets and didn't bother with anything else. I never got an itemized list of what was actually replaced.

[SunSoaked]

Is that an AA bellhousing? If so,did you buy it or did it come with the trans? If you know the part number it will tell you if your trans is the early or late model. There's one for the 93-95 and another for the 96 later. 712577 is the AA # for the early ones.I've got a similar setup as you. I'm curious about the AA kit that addresses the 5th gear nut. I never heard of that?

Edit: I just noticed the AA box in the background of your photo, so I guess I answered the first question.

[mongocanfly]

You can tell early from late yr models by the shift tower....
The early ones had a post style and later ones have the 4 bolt style...

[rgunlock]

Originally Posted by SunSoaked

Is that an AA bellhousing? If so,did you buy it or did it come with the trans? If you know the part number it will tell you if your trans is the early or late model. There's one for the 93-95 and another for the 96 later. 712577 is the AA # for the early ones.I've got a similar setup as you. I'm curious about the AA kit that addresses the 5th gear nut. I never heard of that?

Edit: I just noticed the AA box in the background of your photo, so I guess I answered the first question.

I did purchase the AA bellhousing and it is the 712577 part. When I placed my order with AA about 7 years ago, I believed I had the early NV4500. Regardless of what I've got, the bellhousing bolted up just fine. BTW, I've also got the ORD twinstick (came later than my photo) because I couldn't make the AA shifter bracket work out. It was just too fiddly trying to get the NP205 shift rails to go in and out together. I read somewhere that part of the installation included a collar that doesn't allow the nut to back off if I'm remembering correctly. I'll have to hunt around and see if i can find the reference again.

Originally Posted by mongocanfly

You can tell early from late yr models by the shift tower....
The early ones had a post style and later ones have the 4 bolt style...

Mine has the 4 bolts. They show in my 2nd picture. Now I'm wondering what the difference in the bellhousings is and whether I've got the right one or not. I'll have to look into that.

[rgunlock]

I guess the nut is replaced rather than being held from backing off. This is from the AA website:

GM 32 TOOTH 4WD OUTPUT SHAFT
On all NV4500s that were equipped to a GM 4WD transfer case, you will find that the output shaft has 32 teeth. The adapter housing that is mounted to the back of the transmission case is 8-1/8" long. On the inside of this tailhousing, you’ll either find a vibration damper on the output shaft or a steel sleeve. Most of our transfer case adapters will require the damper or sleeve to be removed. We couple to the 31 tooth spline located under the damper or sleeve. In order to remove the vibration damper or sleeve, you must use a special socket. This socket will be required in order to remove the nut because this nut is put on with 275 ft./lbs. of torque. On transmissions with the damper, a gear puller will be required since the damper is a press fit to the output shaft. On all applications that require the removal of the damper or sleeve, we will provide a custom set collar that must be installed on the output shaft to retain the 5th gear into position.

[SunSoaked]

This has me scratching my head after reading the AA site and watching that slide show. From what I see, the only way that 5th gear nut can back off is if the sleeve or damper have been removed. The damper is pressed on behind the gear and behind that is the input shaft on the t-case. And, I don't get why you would cut the mainshaft off? My 32 spline input 205 bolted right up- no mods required.
Hopefully somebody here who has done it can explain.

[rgunlock]

I "believe" that cutting the mainshaft down has to do with the coupler between the AA tailhousing and the NP205. Mine had to be cut down because I have the 23 spline NP205.

I just got off the phone with AA. Basically, they told me as long as the bellhousing bolted right up I do have the older NV4500 and if it has the newer style shift tower somebody replaced it. So, sounds like I won't have to pull it all back out of the truck due to a wrong bellhousing at least.

[SunSoaked]

Ya, that makes sense on the adapter sleeve.
I didn't realize you already had it in the truck, but if it all bolted in, then it must be the right one.
Quad 4x has good info on the differences. It's all in the mounting bolt holes dimensions.
It looks like those dampers were used on diesals with a dual mass flywheel. Guess that's why mine doesn't have one. Not sure about the sleeve, I don't know what function it has other than take up the space of the damper?

[44th Miss Inf]

Originally Posted by mongocanfly

You can tell early from late yr models by the shift tower....
The early ones had a post style and later ones have the 4 bolt style...

My father bought a 95 3500 with an NV4500 new and the trans has never been out of the truck that has a bolt on shift tower.

[SunSoaked]

I'm looking at my other 4500 from a 94 in my garage and it has the 4 bolt shifter tower.

[mongocanfly]

https://torqueking.com/product/10262...-nv4500-cover/

[SunSoaked]

I'm sure there are exceptions and cases where parts inventory carried over from one year/model to the next. Either way, I have a 92 with the original integral tower and a 94 with the bolt on tower. And, they both bolt up to my early style AA bellhousing.

[Hammered 77]

The carpet will definitely dampen the noise. The transmission housing resonates any noise it gets whether it's from the bearings, the gears or something else. Depending on how things heat up, I suppose the bearings could tighten up a little. If it's really only in 5th gear, I'd also look at the gear set. Again as it heats up the gear mesh will become tighter, and that will definitely affect noise.

[rgunlock]

Originally Posted by Hammered 77

The carpet will definitely dampen the noise. The transmission housing resonates any noise it gets whether it's from the bearings, the gears or something else. Depending on how things heat up, I suppose the bearings could tighten up a little. If it's really only in 5th gear, I'd also look at the gear set. Again as it heats up the gear mesh will become tighter, and that will definitely affect noise.

Thanks Hammered. I drove the truck about 16 miles in traffic, etc. so it had plenty of time to heat up. The noise occurs as soon as I go into 5th regardless of whether it was at the beginning or end of the drive. It just seems to "tone down" after I've been in 5th for a while.

I guess I'm just trying to explain it away as normal so I don't have to pull it back out, but it's not sounding like it I could cover it up enough to drown out the noise and hope things don't explode or pull it back out and deal with it now.

[13jraven]

What fluid are you running? How many quarts?

I have put NV4500s in a lot trucks. Presently, I have three - 2 behind 12vs and an LS3 - and were always noisy unless I ran a 5th quart of the OEM fluid.

Mopar 4874464AB Manual Transmission Lubricant.
Posted via Mobile Device

[rgunlock]

I'm using Amsoil which specifically calls out NV4500 on the label which is shown in post #6. I was under the impression that 4 quarts was the capacity so that's what I used. Adding a 5th quart is no problem. I'm assuming the downside of going over capacity is just the expense of the 5th quart?

[mongocanfly]

I got my last nv built by high gear transmission in memphis...I had heard about the 5th qt thing so I asked them....they said absolutely don't ad the 5th qt....and at $140 a gal I didn't argue....

They gave a explanation but I don't remember exactly the reason they gave..

[13jraven]

My cousin's dog's cat got a NV4500 rebuild by these famous dudes and they said if you transmission is noisy put in an extra quart.

They gave a technical explanation but I only remember the extra quart part.

AMSOIL works but I have had the best luck with the OEM stuff.