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...

[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.
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[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.