Engine/Transmission (1998.5 - 2002) High Iron Count in NV4500 lube analysis

[John Berger]

What part(s) in the transmission would cause a lube analysis reading to be high in iron. Silicon and copper are low as are most other numbers. I had 10K on the lube, probably 40% of that was towing miles. I was using Amsoil Series 2K 75W-90. I have had a hard shifting problem, but it has been intermittent. No grinding, no noises, no vibrations. The hard shifting problem started after I had the SBC clutch installed. When the stock clutch gave up the ghost, it was not a pretty thing to feel or here and I'm wondering if some damage could have been done at that time. The transmission looked clean when I changed the lube. No metal flakes or chunks. The gears all looked good. Thanks in advance.



John

 

[Riflesmith]

How high? Do you have a ppm number for us?

 

[John Berger]

Yeah, sorry. 236 ppm at 80,787 miles.



It was 146 ppm at 55,504 miles.

 

[DEZLPWR]

Originally posted by John Berger

Yeah, sorry. 236 ppm

:--)

 

[John Berger]

Yeah, that's what I thought. I told Blackstone that I was concerned about the synchronizers and they say high iron is a sign of synchros going bad. I thought synchros were made of soft metal. Whatever is wrong, probably started when the clutch exploded. That was tough to listen to that day. The hard shifting started when the new clutch went on. Kind of makes sense. I wonder how long the transmission will last. I've got 80W-90 in the transmission right now.

 

[Pit Bull]

Just wondering why your not using the factory recommend lube? Could this be the problem?

 

[John Berger]

Over half the miles on the truck were with the factory stuff, somewhere in the neighborhood of 48K miles. I didn't have any shifting problems until the stock clutch exploded on me. There was alot of crunching and grinding when the service manager and I took the truck for a test drive and the clutch went while we were on the drive. I never had the slightest shifting problem prior to that. The inside of the transmission looked really clean, shiny and well worn when I changed the lube out. When I took the factory stuff out, the first time, the transmission didn't look so good inside. I did lube analysis on the transmission and the readings were good, except for the iron count. I still want to know why iron counts would be high if synchros are soft metal. My shifting problems are still quite intermittent and I'm not noticing any driveability problems. All of the other readings on the analysis show a downward trend relative to the universal averages. I repeat, I get absolutely no grinding whatsoever when shifting.

 

[Riflesmith]

John,

I think you should seek out opinions from several analysis labs that analyze transmission lubes every day. Ask them how your numbers compare to universal averages. I would NOT expect iron numbers to be as low in a transmission as I would in an engine. I would think that a number somewhere in the 100 to 200 ppm iron would be normal. You have all those meshing gears and no filtration. Call the guy at Oil Analyzers. He explains things very well and doesn't seem to mind spending time with the customer. Best of luck.

 

[catoiler]

John did you change the lube or just sample it?on the report they should of put their recommendation as to what is possibly wrong. I would sample it again in about 1000 miles and see how much change their is.

 

[John Berger]

catoiler, I completely changed the lube out. The report said universal averages were 164. When I sent the lube in I told them I was concerned about the synchronizers. I didn't realize that iron counts would be high if there is a synchronizer problem. Any chemists out there that can straighten me out on that?

 

[amsoilman]

I'm like Riflesmith, do another analysis with a different analysis lab. I too think (Fe) Iron count would be much higher from gears than in an engine. As an example, at 60,000 miles on my rear differential the (Fe) Iron count was 169 ppm. No syncro's in there! Call Oil Analyzers Inc. as Riflesmith suggested. Number is:715-395-0222





Wayne

amsoilman

 

[John Berger]

Thanks for the info. I'll give them a call. Maybe I'll just change out the lube again. I just love the smell of gear lube in the hot afternoon sun.



The other thing I keep thinking about is that I've towed quite a bit in the last 5 months, more than I ever have before in any 5 month span since I owned the truck. All of the trips were in fairly warm weather and were quite extensive in duration. I would expect wear to be significant (as ppm are concerned) under those cirumstances. For instance: the first lube analysis I did on the transmission was at 44K and probably 17-20% of those miles were towing, the rest just driving around town and to work, with the occasional long trip, unloaded. I had 10K on the lube I just had analyzed and the towing miles on it were right around 50%, maybe a bit more.





Update: Out of 10K miles on the lube, 6286 miles were towing my now deceased travel trailer and the new 5'ver.

 

[JJW_ND]

Thing 5th gear wear!!

John,



I looked back through 5sp oil samples and I had Fe counts as high as 726. Only one was under 250. I had further test done on the very high sample and the lab said the particles were gear sluffing and scuffing wear..... 5th gear! Even got a picture of the particles. Shortly their after 5th gear loosens for the three time. The lab I used was CTC Analytical. Very good lab!



After 150K miles and three dropped 5th gears, I replaced with new (should just rebuilt). Sent core to rebuild shop only to find out first four gears like new including syncros. Only had to replace 5th gear and mainshaft. I would doudt high FE will be related to syncros or even cause and increased wear or problems.



Out of all those miles, how many were in 5th?



5th gear, high HP, heavy load= High Fe. Change the fluid and keep running it. Doesn't sound like you are having any heat problems. Did they give you a TAN reading?



Your shifting problems are clutch related not transimsion or fluid. JMO!



jjw

ND

 

[John Berger]

JJW, I didn't ask for a TAN reading. I also didn't tell them how much I had towed with that lube oil. Most of the miles were highway with ambient temperatures anywhere from 84 to 96 degrees at speeds between 60-67 mph. I tried to keep the RPM's over 2000 to avoid the excessive vibration that is suspected as the cause of 5th gear backing off. I didn't start monitoring transmission temps until the middle of the summer. Hottest I ever saw was 210 degrees and that was a very hot day towing my 5'ver. Your explanation about warmer temps in 98 and up NV4500 transmissions is interesting. There are many on here who say they have never seen temps over 200 degrees in the differential or transmission. When towing, I rarely ever see temps stay below 200. Depending upon speed, 205-215 seems to be about normal.