Archived ///// 5th gear nut..... I may have messed up big time /////

[AndrewKing]

HI All,

I lost 5th gear on my 1997 ton truck while towing (1997 dually (4.10 gears) 4x4 towing about 5500 lbs total weight) .

In all my reading here, I deduced that my 5th gear nut had come off so I limped the truck back home in 4th (I hope I did not damage anything by doing so....NOTE: I just read a thread where using a truck with the 5th gear off can some how creates slop in the transmission that can lead to wear on some other internals...I wanted to post the link to that here but the computer timed out and I could not find the thread again)....I have had to use my truck almost daily and more recently on a 325 mile trip.... am I hurting things by continuing to drive with the 5th gear nut off ? I don't hear hear, feel, or smell anything bad so I am hoping not but reading that other thread made me paranoid about possibly hurting other things by continuing to drive the truck.

Anyways, I had ordered an updated 5th gear nut and new 5th gear from the Dodge dealer and I also got the 5th gear "retainer" from fifthgearrepair.com to help ensure I don't have a problem again.

I am supposed to have a mechanic friend of mine come over tomorrow to help (actually do... while I "help") work on my truck, when to my horror , it appears that special tools are needed to do the job (I decided to read the instructions for the fun of it) ...special nut tool 6743 and a special tool to hold the splined shaft (special tool 6984).

As a layperson reading the TSB it seems that the special tools may keep me from getting the job done tomorrow OR can the job be done using alternate methods (mechanic tricks of the trade or maybe using the new retainer from 5th gear repair as the special tool to engage the slots on the new 5th gear nut and using a pipe wrench to turn things....or maybe a hammer and punch to tighten the new 5th gear nut?) .....We can even maybe use a (gasp) pipe wrench to tighten hold the splined main shaft as things are tightened (of course not holding the shaft on the splines or any bearing surfaces)....I know this is not ideal and of course using a pipe wrench is far from ideal but I really need to use the truck and again reading that last post about further damage happening makes we worry that I should not take the long trip I have coming up this upcoming week (about 500 miles total) .

So what do you think?...Can the 5th gear repair be done without those 2 special tools or should I wait until we get the special tools for the job? Also, is there harm in driving the truck with 5th gear off (again the thread about the extra slop and play from the 5th gear nut being missing and damaging the transmission further has me worried.....However, truth be known I have driven the truck a bunch without the 5th gear working....just the new info has me worried too ).

Thanks in advance for any and all help.

Andrew

 

[NIsaacs]

Hi Andrew, it's been awhile

I would not drive the truck until the repair is done. When the 5th gear comes loose you loose your bearing preload on the input/main shaft (both). Does your transmission have the fully splined main shaft? If not, I highly recommend it. Are you going to fully rebuild the transmission or just install the new gear and nut with the transmission still in the truck? You can't use the retainer lock to turn the nut because it is splined to the main shaft. I recommend you buy or borrow a spanner wrench, 3/4 drive is best. The FSM spec is 280 ft. lbs, I recommend 400. If the transmission is out and the top is off you can slip it in 2 gears, that will lock the main shaft and now you can just hold the transmission with a long bar while you tighten the nut.

Nick

 

[Bob V]

you don't need the tool to hold the shaft. I use the baring tool and breaker bar with trans in gear to keep it from turning. Some will use a hammer and punch/chisel to drive the nut. I would use the correct tool for this myself. There is no way to know how tight the nut is with the hammer, but there are lots who do it this way and are successful. If the transmission has never been apart have a good quality 10mm wrench. Some of the bolts arte tight and cheap wrenches will round off the bolt head. It nice to have the torque wrench, but it will be as tight as you can get it with a breaker bar with a cheater pipe, not much room under the truck

 

[AndrewKing]

HI,

Thanks for the replies guys.....I spent a good portion of the early AM researching the special tools needed (unfortunately our Napa and Advance Auto / Fisher auto stores can't even get them).

FWIW the cheapest online store I could find special tool numbers 6984 and 6743 were at Quad4x4.com....they were $93 and $61 respectively....Pretty costly considering I am hoping this is a one time fix (fingers crossed).

I did think about saving $$ by using the hammer and punch method to put the 5th gear nut retainer on but since I bought the splined nut retainer from Fifthgearrepair.com I didn't want to booger up the 4 slots by beating on them....I guess that plus the fact that it would be hard to set a torque for tightness of the nut had me think more about ordering the right tools before opening up the trans....

In reading more about the 5th gear nut issue it just dawned on me that I could (maybe) have bigger issues....

Before I lost 5th gear altogether, I had noticed that whenever I shifted into 5th gear it would be followed by a fairly noticeable "clang" type noise (it felt like there was "slip" in the drivetrain....Also when I let off the throttle in 5th gear there would sometimes be a noise that I associated with "slop" in the drive train.....With that I eventually had all the u joints and carrier bearing replaced (we also checked the rear end for slop when the drive shaft was removed for new U joints...the rear end was deemed "tight".

After the drive shaft was reinstalled, I was disappointed that the fifth gear "clang" was still there.

This brings me to a new potential issue (I was just thinking through all the potential problems but I have not yet looked inside the trans since we don't have the special tools yet) .....could the nut still be on the shaft and maybe the clanging I was hearing when going into 5th before the result of the gear rocking on possibly worn out splines? .....I am assuming that the deteriorated spline theory would make sense given the noise OR does a loosening 5th gear nut also make that noise as well?... worn out or broken splines would be a bad situation since that would require a new shaft and more work than just installing the new 5th gear, new 5th gear nut and new 5th gear retainer.

I am guessing / hoping the splines on the main shaft are harder / more durable than the splines on the 5th gear?....If that is the case maybe the splines on the shaft are fine and only the splines on the 5th gear are messed up (that would not be a problem since I have a new 5th gear ready to install).

Just curious, but I have read numerous posts where people have been driving around in 4th gear with no real bad effects (other than increased engine RPM / worse fuel economy) BUT on the flip side I have also read that the 5th gear nut and even the gear itself may preload other bearings and / or provides additional support for other pieces in the trans and the truck should not be driven until stuff is fixed correctly.....Which is the the correct or more correct situation?....Is the truck OK to drive with the 5th gear not working for whatever reason or should the truck be parked until the trans situation is taken care of?

FWIW....I have been driving like normal minus the 5th gear....UGH so many things to think about.... maybe sometimes ignorance is bliss ha

Thanks again for all the help thus far.

Andrew

 

[DonFitzwater]

"they were $93 and $61 respectively....Pretty costly considering I am hoping this is a one time fix (fingers crossed)." Usually a "one time fix" costs more money than not!

Don't mean to bust your chops but getting out of this cheaply AND reliably ain't going to happen. You should fix this thing correctly and get the fully splined, updated main shaft from Standard Transmission and gear in Fort Worth, Tx. The problem is the fifth gear isn't fully supported, i.e. the main shaft isn't splined the full length. Give them a call and they can walk you through it.

 

[Bob V]

did you read this http://quad4x4.com/NV4500 5th Gear Failures and Solutions.htm
if you just want to get it going again stay with your original plans and then save up for the better shaft. the trans will need to removed and dissembled to replace the mainshaft. I used locktite 680 to help hold the gear to the shaft. it is not cheap but it will help. I replaced the nut at 50,000 miles and stayed together and was still fine at 215,000 when I sold it, and i used 5th gear for towing all the time. Make sure everything is clean with a good degreaser and blown dry and give time for the locktite to cure before you drive it. . I would use 272 locktite to hold the nut to the shaft. if the shaft is excessively worn locktite 660 might be better than 680.

 

[SAndreasen]

Done many a nut with just a chisel and a pipe wrench tight on the splines so it can't slop and . And no you do not loose any end play buy losing the fifth gear there is a bearing retainer plate that holds the bearing with shims also it is end play not preload on an nv4500 big difference also I locktite the gear and nut and let setup overnight

 

[SAndreasen]

You are way to worried about this at the worst your reverse gear is toast on the countershaft depending if the fifth gear chipped a tooth on it when it worked off

 

[MLee]

Guys that have lost there 5th gear stated that the gear was OK, but the threads on the nut was toast. Some just replaced the newer designed nut and the 5thgearnut keeper your thinking about.

 

[SAndreasen]

For the price if the right tool to tighten the nut I'd get it otherwise your goina have to beat it on then dress up the nut so the retainer will fit

 

[AndrewKing]

Hi All,

Just thought I'd follow-up with what happened on my truck and maybe it'll help somebody else in my situation or similar situation....

We got into the transmission and it was found that the nut did indeed back off leaving me without fifth gear....The nut inside was the split type upgraded nut (the one with the set screw that helps clamp the threads onto the threads) so it appears that my truck may have had fifth gear issues in the past (otherwise it would have had the old style nut).

Anyways we did everything per the instructions and added the 5th gear retainer from advanced transmission as extra insurance....hopefully that will be the end of my issues with this trans.

First drive and the clank when shifting into fifth gear or letting off the accelerator and hearing a clank is now gone.....so if you hear clanking in fifth your nut may be working loose....

Drove it 300 miles and so far so good....And yes I admit I have gone as low as 1250 RPMs in fifth on the level so hopefully the retainer works! (Not lugging the engine or using heavy throtte tho).

Thanks again for all your help.

Andrew

 

[SAndreasen]

I've had good luck with a nut www.allstategear.com sells I also replace the gear and use red loctite on the gear and then let it setup overnight .how did you end up tightening the nut?

 

[jw3500Ram]

Just an FYI the 5th gear nut problem is caused by towing and normal driving in 5th when the rpm range is too low causing the motor and transmission to shake more than normal. Just don't have someone weld it in place like they did on my transmission.

 

[SAndreasen]

Just an FYI the 5th gear nut problem is caused by towing and normal driving in 5th when the rpm range is too low causing the motor and transmission to shake more than normal. Just don't have someone weld it in place like they did on my transmission.[

The problem is the splines on the main shaft aren't as long as the gear is deep so as the gear gets worn it can rock on the shaft which pusehes the nut off

 

[SAndreasen]

Just an FYI the 5th gear nut problem is caused by towing and normal driving in 5th when the rpm range is too low causing the motor and transmission to shake more than normal. Just don't have someone weld it in place like they did on my transmission.[

The problem is the splines on the main shaft aren't as long as the gear is deep so as the gear gets worn it can rock on the shaft which pusehes the nut off

 

[K.L.Schumacher]

I went through this in April 2014. I used the Fifthgearrepair dodad and it is still working. Link to my thread.https://www.turbodieselregister.com/threads/247025-Nvg-5-th-gear-fell-off