Engine/Transmission (1994 - 1998) 5th gear nut 3 part question.

[LRamey]

Well it happened again, lost fifth gear and I'm getting ready to leave on a camping trip this coming Thursday. So here's my questions.

1) Will it hurt anything to drive about 800 miles with the gear backed off?

2)Will it hurt anything to run about 4 hrs @ 2700 RPM? I wouldn't think so because they run generators wide open 24/7. Just had to ask anyway.

3) Whats the best permanent fix? Or is there one?



Thanks,

Lonnie

 

[B9Mile]

One of the locals had his nut back off whle he was in Wyoming a couple of years ago. He contacted the local Dodge dealer with basically the same questions you have.



My buddy drove all the way back from WY in 4th gear. He had a hot-shot rig at the time.



The service manager said it won't hurt it to drive it like that. Just watch the transmission temperatures. Personally, I wouldn't drive it too much until it was fixed. There may also be some metal wear particles and other things related to the nut's failure floating around in the oil.



These engines are designed to run full load for extended periods. You should be ok, if your ears can stand it.



WHEN my 5th gear nut comes loose, I will probably remove the transmission and just ship it to Standard Transmission & Gear for the fully splined main shaft change-out. This is pretty much the only real solution.



You can buy the parts and fix it yourself, or have a transmission shop install the new main shaft.



http://www.standardtransmission.com

 

[LRamey]

B9Mile

Thanks for the info! I went to the Standard Trans. web site & looked at what they have. Sounds like it's what I need. I'm afraid I'll just have a repeat of what I have now if I go for the locking nut like I did 2 years ago.

I figured it wouldn't be a problem for high RPM's but like you say, if I can stand the noise. The nut came loose today about 100 miles from home & I pushed it about 65 all the way at around 2500 RPM and it wasn't too bad.

Thanks again,

Lonnie

 

[Fred Swanson]

Pier's has a design that has 2 set screws on the nut that I have used and it has held up fine. Not expensive at all.

 

[gitchesum]

Something else to consider.

I thought my 5gh gear nut came off early this year. Turns out, it was a snapring that held the 5th syncro assembly on the countershaft. The assembly was sliding too far back, The only thing that prevented it from coming completely apart was the tail section casing. But, it did chew up he inner gears of one part of the assembly and it needed replacing. The guys at Bluemthals said this isn't the first time they had heard of this happening and sent me a new gear with a two thinner snap rigns instead of the one thick one.



Here's a picture of the gear that was chewed up, click on the picture for a bigger one.







Here's a good shot at the 5th gear syncro assembly. That gear rides right a the end of the bottom shaft, the snap ring was supposed to hold it in place on the shaft. CLick on the picture for a bigger one.

 

[RAndrae]

just did 5th gear

My 96 3500 with 136, 000 mi (ORIG transmission OIL till 132,000 and clutch) lost 5 th last weekend. I was pulling 10,000 lbs and it was just like going into neutral. I drove it for about 100 mi with no problem. On monday I contacted Standard Transmission and South bend Cluth and ordered the updated shaft, new 5th gear, nut and a rebuild kit along with a clutch respectivly. BOTH Standard Transmission and Southbend were GREAT very helpful and great prices. Upon rebuild the transmission was fine with very little wear and no oil related problems. The oil was dirty and appeared to have fine metal in it. I would say that this was from the gear and nut floating on the shaft. I would drive a transmission with no 5th only if I HAD to.

 

[Wally]

had a friend lose 5th in Maryland last year and drove home to AZ then took to dealer for repair all they did was nut replacement no other problems were reported all under warranty

 

[RCapehart]

I lost mine last July with 81,000 on the truck. I towed 8,000lbs 200 miles to get home. I used the nut kit with two set screws from Blumenthal's. Also I got a press fit 5th gear. The old gear looked fine the shaft did two. But it had a slight wobble to it. The press fit gear fit tight. They claim no ratchet action going on this way. They said they were having good success with this fix with stock motors. I guess time will tell!!

 

[LRamey]

Just wanted to say thanks for all the replies. Here's what I'm doing. I had called Standard trans. and ordered the new main shaft, fifth gear & nut today. Then I got to thinking that it has seemed like one of the syncro's has been acting like it's wearing out. I spoke with Standard again & they said they are having a special on rebuilt NV4500's right now for $1250. 00. I called the wreaking yard and they want $1700. 00 for a used one!! So I called back and ordered the rebuilt from standard. All told I'll be out around $1800. 00 and a bunch more peace of mind. (yes their rebuild has the new style main shaft)

One of my biggest concerns was if my mechanic opened it up to replace just the main shaft and found a bunch more stuff wrong, I could be out a lot more then a rebuild.

Thanks again everyone!

Lonnie

 

[Joseph Donnelly]

Yer right, Lonnie. And, Standard really knows those trannies so the clearances etc. will be right on spec. I've seen a number of rebuilds that were not as close as I would like. If the nut has come off, the gear splines have hammered into the stock mainshaft and the gear can wobble under high torque. Even with a new nut, it can and will come off again, eventually. The fully splined mainshaft is the only real fix. Also, the threads on the nut usually strip off so all that metal goes into the sump. If you are lucky, the magnet inside the driver's side PTO cover wil catch it. If not, the bearings will get the rest So, you are better off not driving after the nut comes off. Standard's upgraded nut has three set screws that drive brass plugs into the mainshaft threads.

 

[BWilson]

I just had to put my $. 02 worth in... ... I put the standard transmission main shaft kit into my transmission approximately 200K miles ago and it has worked great ever since. I also heard of a few people the lost fifth gear put a big magnet on the pass. side PTO cover to help grab metal shavings and when they fixed it they really didn't see much on it. It should be in some of the old threads.



Oh yeah, the South Bend clutch works great too!! Both companies were great to deal with!!