Engine/Transmission (1998.5 - 2002) nv4500

[OakViewJeff]

NV4500 Main Shaft damage after 120K on my 1st rebuild from ST.

 

[SAndreasen]

View attachment 93293
NV4500 Main Shaft damage after 120K on my 1st rebuild from ST.

that looks ugly havent seen that before even on the last one i did where somebody ground the threads out of the nut drove it on and welded it to the shaft

 

[BigPapa]

NV4500 Main Shaft damage after 120K on my 1st rebuild from ST.

Standard did the rebuild or it was rebuilt with Standard parts?

 

[OakViewJeff]

The main shaft in the picture I posted was from the rebuilt NV4500 I bought from ST in Texas, to replace my original NV4500, after 5th gear slipped off the shaft. That's the risk when buying a rebuild, you get some used parts from the previous owner. My second rebuild by ST was done in Tucson by Richard Pooles. He replaced the main shaft, complete bearing kit, 5th gear counter shaft, 5 gear, and 5th gear bearing. This 2nd rebuild shifts smoother than the 1st rebuild and the OEM NV4500. Great service, call him at 817-625-7109 if you need your transmission rebuilt.

 

[KATOOM]

I was told by Quad4x4 that even though the aftermarket shafts are fully splinned, the quality of metallurgy of them is considerably less than the OEM non-fully splinned shaft. It seems our options of where to get transmission parts is limited to China or Thailand. Sad that everything is from the orient.

 

[SAndreasen]

I was told by Quad4x4 that even though the aftermarket shafts are fully splinned, the quality of metallurgy of them is considerably less than the OEM non-fully splinned shaft. It seems our options of where to get transmission parts is limited to China or Thailand. Sad that everything is from the orient.

thats exactly why i didn't go with a reman because i didn't want a cheap china transmission quad 4x4 has some oem parts but hes getting sold out of them. after seeing just how much metal went through this one i am beginning to think maybe i should have got a different trans seems to run smooth though. i dumped 10 gallon diesel fuel through the top of the case then a gallon of cheap gear oil and then 2 quarts oem nv4500 oil i also installed a filter kit and put two magnets in the bottom of the trans case

 

[surfbeetle]

http://fifthgearrepair.com/nv4500transmission.html has a kit to keep the fifth gear in place on 4x4 trucks only. Also I use royal purple oil in mine and have 230,000 miles on my original OEM transmission over the last twenty years with lots of towing.

 

[KATOOM]

http://fifthgearrepair.com/nv4500transmission.html has a kit to keep the fifth gear in place on 4x4 trucks only. Also I use royal purple oil in mine and have 230,000 miles on my original OEM transmission over the last twenty years with lots of towing.

That little device has been around for some time now and I keep trying to find more feedback about it. Catch though is that it has to be in a 4wd version as it doesnt work in the 2wd transmissions. I dont hear much about them either but then I'm not sure how many people use it on the forums. I did hear once about a person blowing out the transfer case housing after using it but I couldnt say how accurate that was either.

I'm also glad to hear you're successful using RP. Usually shifting issues are common after using aftermarket fluid. How long have you been using RP in the transmission?

 

[SAndreasen]

That little device has been around for some time now and I keep trying to find more feedback about it. Catch though is that it has to be in a 4wd version as it doesnt work in the 2wd transmissions. I dont hear much about them either but then I'm not sure how many people use it on the forums. I did hear once about a person blowing out the transfer case housing after using it but I couldnt say how accurate that was either.

I'm also glad to hear you're successful using RP. Usually shifting issues are common after using aftermarket fluid. How long have you been using RP in the transmission?

you could potentially screw up the housing if you didnt test fit the case clerance in relationship to the retainer the instructions on the fifthgear repair site says you may have to remove up to .050 from the transfer case side of the retainer and that the problem is most common with aftermarket main shafts and nuts . i have the retainer installed and then measured the depth from the seal bore in the transfer case adapter to the retainer and then compared that to the length of the input shaft on transfer case and it shows plenty of clearance but im still going to take it slow and easy when i mate the two untis together

 

[SAndreasen]

Heres the fifth gear repair retainer installed

 

[SAndreasen]

Decided to paint while I had it out

 

[surfbeetle]

I'm also glad to hear you're successful using RP. Usually shifting issues are common after using aftermarket fluid. How long have you been using RP in the transmission?

I've been using RP for several years now, I think it's been a decade. It's about time to change it again.

 

[KATOOM]

What RP fluid exactly are you using?

 

[ursusarticus]

If I were to rebuild that transmission, I'd magnaflux every gear and the case to make for sure that there no other cracks. In your case I agree that a replacement gearbox is the best way to go. The most common issues I've seen with manual transmissions have been damaged blocking rings, bearings, or thrust washers. A broken gear tooth causes many other issues to happen. That being said you are right to "drop back 15 and punt" What kind of "shock load" did this box see to peel teeth of an overdrive gear?

 

[SAndreasen]

No shock load crusing 65 and made a real bad noise towing heavy luckily was only a couple miles from home took it easy and parked the truck . I think what caused it was losing fifth gear 3 times previously and not replacing the gears because the nut just doesn't fall off it would run for awhile with the teeth partially meshed

 

[KATOOM]

There's plenty of speculation as to what causes the 5th gear to fall away from the shaft. Some think its because of the harmonic pulses the low RPM Cummins engine generates, so therefor the advice is to not tow any slower that 1500 RPM. Personally I dont think thats an accurate understanding of whats going on in there and has nothing to do with the problem.

I believe the accurate reason is because of the ON/OFF throttle driving habits some people unknowingly have whereby they dont realize how abruptly they cycle from cruising along to no throttle. That ON/OFF slack isnt really a problem in all other gears which are fully supported on both sides, but this violent action shocks the partially supported 5th gear/shaft splines and rocks the gear loose. At least thats my thoughts.

In saying that, its also no secret that towing in 5th gear creates tremendous heat. That tells ya that the little 5th gear is running really hot and if it gets hot enough then it potentially alters or affects the metallurgy of the gear/shaft. Its also known that once the gear does fall off, getting it to remain in place without replacing the whole gear and shaft is very slim and usually means repeated fixes.

Just my opinion.....

 

[SAndreasen]

with the fifth gear repair retainer there is no way that the nut can get off

 

[surfbeetle]

What RP fluid exactly are you using?

Royal Purple Max Gear 75W-90 GL-4 rating

 

[KATOOM]

with the fifth gear repair retainer there is no way that the nut can get off

Technically thats correct.....there is supposedly no way for it to come off.

 

[SAndreasen]

Technically thats correct.....there is supposedly no way for it to come off.

man i hope so . i went ahead and loctited the gear to the shaft i have done this before and when it comes time to pull the fifth gear it takes a 10lb hammer and chisel to brake it free . another thing you could do is weld the retainer to the nut and then it would be impossible for the retainer or nut to move