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NV4500 finally died...

Mopar1973Man
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dripley

dripley

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It interests me. The worst I have seen is near 220* with the 5th wheel in tow. That was in near 90* weather in some hill country but no long grades and using OD. I could get it to drop to around 195* using 5th a little more, but fuel consumption was up some. Made 2 almost identical trips a while back, one never coming out 5th and the other using 6th like I normally have over the years. 5th netted me just under 10 mpg and the return using 6th a lot and netted just over 11 mpg. But the tranny does run hotter, 20 to 25*. What is the danger zone on tranny temp for a manual? I run Penzoil synchromesh but did not see anything on there site as what temp range is ok.

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IBMobile

IBMobile

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1 hour ago, dripley said:

What is the danger zone on tranny temp for a manual?

 At temperatures over 200°F the EHL (elastohydrodynamic lubrication) film can start to brake down.  When the temperature reaches 210° to 220°F an oil cooler is recommended.  When the temperatures go over 220°F oil degradation occurs very rapidly and by 250°F the oil is junk and will no longer supply any wear protection.    

 

2 hours ago, KATOOM said:

I did blanket the 6 feet of exhaust which passes directly by the transmission and transfer case which offered even more reduction in transmission heat.

It is suggested to insulate any exhaust pipes near the transmission but do not insulate the transmission.

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Wild and Free

Wild and Free

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9 minutes ago, IBMobile said:

 At temperatures over 200°F the EHL (elastohydrodynamic lubrication) film can start to brake down.  When the temperature reaches 210° to 220°F an oil cooler is recommended.  When the temperatures go over 220°F oil degradation occurs very rapidly and by 250°F the oil is junk and will no longer supply any wear protection.    

Those numbers are really low "one can safely add about 30-50* to what you posted" and every oil has its own set of specifications one must check first to determine what the safe limits are for your specific brand and weight of oil.

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Mopar1973Man

Mopar1973Man

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7 minutes ago, Wild and Free said:

Those numbers are really low "one can safely add about 30-50* to what you posted" and every oil has its own set of specifications one must check first to determine what the safe limits are for your specific brand and weight of oil.

 

Kind of like @Dynamic discussion of transmission temperature gauges and temperature ranges of normal for ATF+4. Even he was on the low side at 220*F if I remember right. I'm going to invest in a ISSPro trans temp gauge for the NV4500. Foolish not too.

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Wild and Free

Wild and Free

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6 minutes ago, Mopar1973Man said:

 

Kind of like @Dynamic discussion of transmission temperature gauges and temperature ranges of normal for ATF+4. Even he was on the low side at 220*F if I remember right. I'm going to invest in a ISSPro trans temp gauge for the NV4500. Foolish not too.

Autos are different than manuals in regards to oil temps, totally dependent on where the temps are measured at in an auto "could be deep frier hot coming out of the converter and show 30-50* less in the sump" where it is not in a manual, you have a case and sump and that's it.

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Killer223

Killer223

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this scares me. how many miles on the trans? my stock 48re has 230K and no major signs of failing. always clean inside at the 30K oil and filter change intervals.

i'm in the market for a new truck was wanting a manual. but if they don't last... maybe an auto is a good option?

 

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KATOOM

KATOOM

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Just to make it clear, I have no idea what the transmission temperatures were before the Fastcoolers and temp gauge installation.  But I have read from other hotshot drivers over the years that their 5 speed would run around 225* to 275* while towing, and after installing Fastcoolers they averaged a 25*-50* reduction overall.  I'm going to assume that they were towing in 5th gear too but I cant confirm since those guys have since moved on to newer trucks and/or are no longer part of the forums.  Towing in 5th (OD in the 4500) generates a lot more heat unloaded or towing.

 

My temperature readings from the transmission after the cooler/temp gauge install was around 150*-175* unloaded in 5th gear and around 190*-220* while towing in 4th gear.  These readings were during the warmer summer weather and on the highway and sometimes climbing in altitude whereby the hottest temp would be after long hill climbs in warm weather and possibly having to downshift into 3rd gear too.  Pointing out that I never tow heavy in 5th gear either.  Strangely what I noticed was that the transmission temps almost mirrored the differential temps too.....  I've since installed a Mag-Hytec which has changed those figures as well.

 

Well after not being happy with the transmission temps while towing up hills I realized that the exhaust was very HOT and it had to be heating up the neighboring transmission.  So I installed two 3 foot exhaust blankets back to back totaling 6 feet which now covered the hot radiant exhaust passing next to the transmission and transfer case.

 

After the blankets the transmission temperatures dropped around 25*-40* overall.  Now driving unloaded along the freeway in 5th gear my transmission runs about 140*-150* at the hottest, and when towing my trailer in 4th gear it will only get about to 160*-175* unless I'm pulling a steeper hill in 3rd gear whereby the peak temperature may reach 200* if the climb is long enough and the ambient temp is hot enough.  That said, if I have the momentum and RPM's before starting the hill which will allow me to sustain 4th gear throughout the entire hill then the temperatures will hardly increase above that 175*.  Clearly running in 1:1 direct drive removes a massive amount of stress.

 

After installing my RV275's I noticed a nice gain in HP while actually allowed me to maintain 4th gear more often and the transmission runs cooler while towing.  Hope that helps. :thumbup2:

 

 

As for oil temperatures and whats acceptable.....  After having quite a few technical discussions with some large name oil company tech guys (leave the company names out in order to remove bias opinions here), they all told me about the same thing.  ANY petroleum oil (which makes up pretty much everything available to the everyday consumer) will start to oxidize at around 180*F.  Temperatures up to 225* was completely safe and some may even do just as well at 250*.  But when you crest that figure the thermal breakdown and oxidation rate becomes immense and the oil begins loosing its ability to lubricate.

 

Running a thicker viscosity is only in attempt to achieve a specific "running" temperature which is why its generally called for in more stressful applications.  So running a thicker gear oil is not always best.....and running synthetic is not always best.  Some actually said I "might" see a slight reduction in overall temperatures by around 10* is I used a 80-90 weight instead of the 140 weight.  I have yet to try though and I'm not sure I ever will.  A lot of what the oil has to go through will be determined by the size of the drivetrain components and the stock capacity.  Which is why a Toyota calls for 140 and a class 8 differential calls for 90.  And, why I installed my Mag-Hytec on my differential and my Fastcoolers on my transmission.  Both gave me added fluid capacity which is better for heat dissipation and lubrication durability.

Edited by KATOOM
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jlwelding

jlwelding

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My NV4500 has been jumping out of 5th for about a year now (maybe 3 times a month). It doesnt jump out hard it just slips out no bad grinding. I changed the oil a few weeks ago and had two 1/4 inch chunks of metal laying in the bottom. The good thing is they hadnt been picked up or chewed on. She has 315K now so I am just going to see how far she will go.

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Explosives87

Explosives87

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I feel you pain mike I just rebuild my NV5600 and I just killed my VP monday after I filled up with diesel. I got 215k out of my NV5600 and I am guessing that its still the stock VP died at 235k. Good luck on the finding a replacement or on the rebuild. I would give south bend a call and see if there is dealer in the local area that they might know of that can rebuild it for you.

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Mopar1973Man

Mopar1973Man

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I don't have either. I'm looking to do a single ISSPro Trans Temp gauge and the two sensors. One for the transmission and then one for the rear differential then add a toggle switch to toggle either transmission or rear differential temps. I'm thinking ahead on this one...

Edited by Mopar1973Man
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