DRam11

With about a thousand miles on a rebuilt NV4500 in my '97 the transmission began rattling in 5th gear when towing. Within a few hundred miles of towing it was making noise in 4th, then 3d. I talked with the rep, who assured me there was a bulletproof warranty, told me not to worry, and then said . . . never tow in 5th gear. His claim was that doing so would cause overheating, which in turn would ruin the lubricant and destroy the transmission. Hmmmm. I know about not towing below 1700 rpm or so in 5th, downshifting on hills, but have never heard one should never tow in 5th.

When I talked to the shop foreman he wondered if it was the transfer case. Maybe, but all transmission noise stopped when the new one was put in. Well, for a thousand miles or so.

Any comments? Advice?

The transmission is coming out tomorrow and going back to the rebuilder for inspection and possible repair.

etn550

Any rebuilt nv4500 had better have had the 5th gear nut problem addressed. This is basic stuff. With that said tow as much as you want in 5th just keep above 1450 and downshift when the pyro climbs and the boost falls off. I used to tow cross country with 27k gross combined with 5th gear AND Gearvendors OD. If I was above 1750 I kept the hammer down. My trans had a Chrysler dealership fix on the nut. That was a '94 with nv4500.

Either way this has nothing to do with noise. And you will have some noise from any transmission that is in a gear other than direct, which is 4th on the nv4500. Increasing noise after a rebuild? That is it keeps getting louder with more miles driven. Something is wrong. Very wrong.

A rebuild that is noiser than the original, I can believe that and of itself is not a problem necessisarily.

The 5th gear nut problem does not make noise. The nut backs off and you loose 5th gear. It just backs up on the shaft and does not engage. No noise, and no damage. Just no 5th gear. The 5th gear nut problem is the only reason for not loading it in 5th. Since yours was rebuilt it should be a non issue so tow in 5th loaded.

I'm betting something was not seated all the way on the rebuild and has worked it's way loose or increased clearance to cause noise. I would check the input shaft gear and countershaft drive gear as these are the only two that transmit torque in every gear except 4th. maybe a bad bearing as well. Or some dirt or metal was on a part or in the case. Or a snap ring was not seated. Lots of things to check.

It needs looked at before there is further damage.

dieselfreak21

Having just been through this my self, here is what I know. 1st find out what main shaft they rebuilt it with to know weather or not you should be towing in 5th. If they put in the factory main shaft, the dodge "fix" will hold up but not very long if you are pulling over 20k gross or have the motor turned up. Their fix is locktite and a nut that has a set screw to give it more clamping force. It doesn't address the issue long term and can still back the nut off. The 2nd option is a fully splined 5th gear on the main shaft. It's better and uses the same nut as the factory upgrade. It allows the touque to be spread over the entire shaft instead of just partially like the factory design. It is probably the best value for the money but the fit between the 5th gear and the shaft is not a pressed fit, it is slip on. There for it will still allow the gear to rock and eventually the splines will break and it will be noisy as the nut usually doesn't come off, and the worn out splines grind against each other all the time. That usually doesn't happen unless extremely turned up and towing over 20k regularly and lugging it in 5th alot. The 3rd option and appears to be the longest term fix is TourqueKing made by a place in Montana. It uses a modified shaft, 5th gear and nut asembly that has a pilot bearing and thrust washer. It stops the rocking of the gear causing the wear.

The factory shaft and the fully splined shaft are about the same price. The full splined is the better option of the 2 and i would recommend it if you aren't planning on a lot of miles on the truck. From the transmission shops I talked to you should get 100k out of the fully splinned pulling 20k plus and turn up truck, towing in 5th, if you don't lug it and easy on the go peddel. The factory shaft can expect less than 100k if over 20k or turned up.

The torqueking setup will probably last the life of the tranny turned up and towing heavy which is about 200k.

The torqueking is also the most expensive. The shaft is over 800 bucks. If you town alot and will be racking up miles that is what I would go with.

I went with the fully splined on mine due to cost as I don't drive the truck daily and might put 10k on the truck in a year. I have turned down the chip to lower setting when towing and and if it get below 65 mph it goes into 4th and I am very easy on applying my right foot in 5th empty or loaded.

I know you have already had your's rebuilt so find out about the shaft. If they didn't pull the fully splined in, then look up the company that makes the torqueking called quad4x4. They make just a 5th great nut that will make a factory shaft last by adding a bushing and modified 5th gear and their thrust washer setup. It is a little bit pricey but if you don't have the fully splined you will have troubles it plan to tow alot, tow heavy or tow turned up.

etn550

Good detail.

DRam11

Thanks for the input.

The transmission is back. Apparently a thrust washer had ground its way into the reverse gear. Inland Truck Parts repaired the transmission under warranty. By the first part of next week the pickup should be back in my driveway.

The fifth gear shaft is fully splined, so there should be no worries about fifth gear given the limited amount of pulling we plan.

From other posts searched out it sounds like towing in 5th gear is okay if the rpm is kept above 1750, and a downshift to 4th is made if the engine is lugging. That's something I've always done anyway, so no worries.

Thanks again for the words of wisdom.

DRam

rich

run an extra qt of oil also. Its even better if you get the coolers and run them also

dieselfreak21

Yep that too will help.


I wouldn't be worried about the fully splined. Got about 2k mile of towning over 20k lbs on it and solid so far. If it gets to 1900 rpms, I start the down shift to 4th my self.

dieselfreak21

the one on the left is in my tranny. The one on the right is the worn out factory shaft.

birddoctor

Where can you find the coolers? I would like to have them for my transmission.

haulin-rv

Geno's garage sells them.



BTW I towed commercially with my 99 w/ nv4500. The first owner had the 5th gear issue twice, but that was back when they just had the updated nut. I put a trans in it too because of another failure, my failure had nothing to do with 5th and I towed in 5th a LOT.

birddoctor

Thanks haulin

DodgeChallenger

Haulin - do those coolers fit the 2007 5.9 6 speed manual. I see where they go - on the sides where the covers are. Soooo simple.

GAmes

You may need adapters for the G56. My coolers are Fast coolers that I had on my NV4500 and needed them. Also available from Genos.