KATOOM

My differential heats up way before the transmission does. Keep up the updates Mike. Good info.

Very true. Good thinking.....but how would I fill it back up? I guess I could put a tee on top too. Really what I planned on doing was later on converting half the fittings to JIC so I can easily take off the hose, but after searching for weeks on end I was getting bored of trying to configure something from internet pictures and just needed whatever I could get to mock up what I have.

The hose will only bend so far before it pinches and then that would be bad. Plus I cant have it pointing straight up and down because then the fluid will always fill the entire length of the tubing due to the height of the fluid level kinda proving pointless unless the fluid level drops well below safe. So I ended up with a radius curve to allow a real time constant visual confirmation of the fluids level and condition. Seems to work..... Important to point out is that this isnt your everyday poly tubing you find at the hardware store but rather FEP tubing which is rated -100*F to 400*F.

Thank you.

Dont forget that those non-greaseable ones are STOCK and have been in there for going on 300k miles..... Thats not to put a time line on non-greaseable verses greaseable either but merely making a valid point.

The drone will prove to be a problem for just about any aftermarket exhaust system merely because those companies didnt perform all the costly R&D the vehicle manufacture did in order to tune the exhaust note. Aftermarket exhaust companies tend to simply make it more free flowing for optimal performance. These Cummins engines will always drone around 2000-2200 RPM simply because of the number of cylinders firing per the sound wave traveling speed within the pipe. Fascinatingly most cars with aftermarket exhaust will suffer from drone around the same RPM range too. The tone of the reverberation can be changed with pipe length, bends, material density, and anything which will change or interrupt the frequency of the exhaust pulse. The best method is a 1/4 wave resonator tube but ya just rarely hear of people trying it. Maybe because it can be a little more involved. Here's a terrific write on a how to build a 1/4 wave resonator pipe. http://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/how-build-exhaust-resonator-tube-eliminate-drone-489463/

Backpressure is a variable only for naturally aspirated engines because of the reliance on intake velocity, vacuum, and scavenging in order to best the combustion chamber efficiency. Charged engines dont run under those same parameters and require zero resistance expelling exhaust as all entering intake air is crammed in. That said, in case someone asks why not run no exhaust..... Dont mistake the need for header/manifold tuning which maintains optimal exhaust valve temperatures..... Therefore on a charged engine the more free flowing the exhaust, the better. But whats ample?..... Well that depends on the setup. Stock exhaust mufflers just sucks but if its straight piped or has a sizeable aftermarket straight through muffler then it works. But a 4" system will prove to be the best intermediate exhaust and more than enough volume until power numbers reach well over 500 HP.

Is there anything else done to the truck? What exhaust and intake? Any other history which may help?

I have the 4500 and Fastcoolers and have collected some data over the past couple years..... Do I think they're worth it?.....yes. But are they for everyone?.....no, not really unless you pull heavy and run outside any gear other than 1:1 direct drive. Heat is bad and all petroleum based fluids will begin to oxidize over 180*. Over 225* and the thermal breakdown begins to increase exponentially. First off, the hot exhaust pipe running right next to the transmission throws off tremendous heat and will most certainly cause the transmission temperatures to rise. Especially when anything like the aluminum Fastcooler runs within an inch or two of the exhaust pipe..... How do I know?..... Well I was confused as to why my transmission temps were running so hot when pulling on grades until it dawned on me that the 1000* exhaust pipe had to be playing a part in those tranny temps. So I blanketed (not wrapped) the exhaust and my tranny temps dropped about 30*-40* on long hot pulls where EGT's maintained the 1000* range. Yeah.....thats a significant reduction in running temps. If I can maintain direct drive then the tranny temps will generally get no hotter than 175* under the most strenuous of pulls. But if I have to drop to 3rd gear then the temps will rise and climb up to 190*-200* if the grade is long enough and steep enough. Let me be clear too that these temps are NOT during the everyday driving or even with any lighter loads behind in tow. ONLY while towing a massive 5th wheel up looooong grades in ambient weather of around 80* - 100*. So I cant even imagine how hot the tranny would get if I didnt have the Fastcoolers and exhaust blankets. I have read of older hotshot drivers mentioning transmission temps in the 275* range! I didnt care to bother with the filter either merely because I didnt think it seemed like a very functional device. It only a string filter with a magnet inside meant to trap metallic debris..... So I just run some extra strong magnets on the PTO covers to hold any floating metal particulates stationary. The 4500 holds about 4.25 quarts. Each Fastcooler holds an additional quart (6.25) and I put the remainder of the 7th quart in through the tower. So 7 quarts is in there. As for replacing the fluid..... Well I dont rack up very many miles on my truck so it may be awhile before I do.

Interesting. Do you think he could supply you with some printable data with that information because I was comparing the differences between the Mobil you're trying out and the SyntorqLT. Thanks.

Agreed that running greaseable verses non-greaseable u-joints is to each is own..... But I can unequivocally say that every time I would hit greaseable u-joints with the grease gun I would think, "wow, look at all that gross contaminated grease squeezing out". Although I've NEVER pulled the cap off a non-greaseable u-joint and found any contamination. Non-greaseables dont wear out because you cant get the contaminants out but greaseable most certainly will..... Next time you have a greaseable u-joint next to a non-greaseable -joint take notice of the obvious difference and quality of the cap seals whereby greaseable have a single weak seal to allow grease to pump out and non-greaseable have three tight seals which snap into place keeping grease in and everything else out. Which one does a better job of sealing..... Here's a good analogy.....how many people run to tear apart their front wheel bearings every time they cross a creek? But for some reason its protocol to grab the grease gun and pump a little goo into the u-joints after water crossings..... Whats the difference?

Its not "what" they use as its more "how many they do and how they do it"..... I have all the common everyday tools for changing u-joints too but I dont bother with them anymore. In saying that, I only use non-greaseable u-joints with quality grease and the last time I had to change a u-joint was around 10 years ago. If quality Spicer non-greaseable joints are used with quality grease in the caps then dealing with u-joints should be a very infrequent event..... As for the little hop, no one has found a pin point component which supposedly causes the 45 mph hop. People have fixed it with new shocks or new tires (as I did) but I've come to the theoretical opinion that the hop is related to the mounting of the engine and transmission, whereby any driveline movement will cause the engine/tranny to move in a harmonious movement which transmits feedback to the passengers as a hop. Sometimes when you hit road bumps a certain way you can almost feel the wiggle of the transmission too. I'd like to replace my transmission mount with a polyurethane mount but my truck no longer hops so its not high on my priority list.

Just curious as to where you found this particular information.

The transmission and differentials are regular 3/4" NPT. But the transfer case is tapered 22x1.5mm. Not very typical. I installed a sight plug on the transmission as I have it overfilled and use the sight glass as a visual confirmation for the amount of fluid in the transmission as much as its color condition.....because obviously (and as already pointed out by others) the level of the fluid would have to be overfilled otherwise you wouldn't see anything unless you were driving and fluid was sloshing. Important though is that you'll want to make sure the temperature rating of the sight glass you're looking at. They're not all high temp and some are actually so low of temperature rating that I wouldn't suggest using it because you wouldn't want to chance the sight glass failing. I eventually found a 500*F sight glass in 3/4" NPT, although it didn't come with a reflector, but I wasn't able to find the right thread pitch in a sight glass for the transfer case which also had the correct temperature range. I'll post some pictures as to what I installed on the transmission and the solution to not finding what I wanted for the transfer case tomorrow.

This is where I tend to go against the grain of DIY. Yes, I completely agree that replacing u-joints is a simple task for those who've done them often.....but a task which is VERY easy to screw up too if you're not careful. You can unknowingly smash a slipped needle bearing in the cap, over press the caps into the yoke binding the caps, bend the yoke ear, etc..... All of these would go undetected too until you installed the driveshaft and found a new harmonic vibration. For this reason I no longer mess with my u-joints as I have many times in the past but now merely take the complete shaft to a reputable driveline shop and say please install some new u-joints. They usually charge very little additional to the cost of quality "non-greaseable" u-joints and you're on your way. Some may balk at this advice but there's a few things I'll no longer bother with an u-joints are one of them..... In regards to the slight shake at 40 mph you mentioned, I'm betting this is nothing to do with u-joints. 1) u-joints dont "shake" or wobble but will hum a harmonic vibration (like a massage tool) and get worse the faster you drive. And 2) I'm sure the shake you're feeling is better described as something like the rear tires feel slightly egg shaped between 40 to 45 mph which gives a little hop feel in the rear. That sound more like it?

Good information and maybe.....just maybe this is a viable replacement fluid for the 4500. And potentially the reason you're seeing lower overall temperatures relative to the load is based on the lighter viscosity, since a heavier viscosity will always run hotter simply due to the increase in friction having to churn through it. SyntroqLT is a 75-85 and I believe what you have in there now is a 50 right? The temperature safety values of the fluid isnt a variable for me simply because ANY fluid over 225* is too freaking hot for my taste and would pose as a problem. But if you can prove with your monitoring that this Mobil fluid is capable of maintaining well under 200* then thats awesome..... Keep up the reports and lets see what this stuff does over time and in the summer heat when you have a trailer back there.

I agree about the differential ring gear sling under an extreme situation, but I would probably be more safe to bet that Mag-hytec used that sensor location simply because its up high and safe from debris rather than anything to do with accuracy. And in saying all this, really think everyone is over thinking the sensor placement within these two scenarios. Not only is there just a mere "one gallon" of fluid being measured here, but also worth pointing out that fluid temperature simply doesn't change rapid enough to justify a heat dissipation range people are suggesting when there is no heat dissipating component involved, especially in a tiny iron case. Plus if anyone thinks the fill plug isnt getting the necessary fluid contact.....then try taking your fill plug out and driving to town. Lets see how much pukes out before you get there..... I'm betting the case will be close to dry. And if someone is going to try and tell me that by the time fluid slings off the gears and tosses over to the sensor that there will be a significant reduction in heat via some level of unknown dissipation.....then this whole conversation is beyond the scope of simplistic gauges available to the everyday consumer. And if that kind of heat difference is the case then to best the situation at hand it would be better to drill and tap the case in multiple locations for multiple sensors just to assure all points of fluid contact with every gear and bearing is vitally monitored. Yes, I agree in that making sure the sensor is placed on the opposite side of the exhaust just to be sure no radiant heat is involved placing any direct heat on the exterior of the sensor itself..... But other than that, the one gallon of fluid crashing around the constantly turning and churning gears inside that tiny confined space is going to mix up any temperature differences about as fast as a blender mixing a margarita. IE, pretty quick. Now if we were discussing an automatic which has cooling lines and coolers involved in this conversation then absolutely there is a definite reason to be assured of the sensor location because you will have a significant reading variance from one location to another. I also agree that an external reading with a laser temp tool will be reasonable at best, but it will still give enough understanding of whats going on overall. Nonetheless, "real time" data with an internal sensor is always going to be the best case. Lastly, just pointing out that the temperature increase in 3rd gear is most definitely from the ratio reduction and nothing to do with higher fluid level from a lower speed. Same thing will apply to 5th gear.....or any other gear besides 1:1 for that matter. Thats not my suggestion or opinion either but just physical fact as any gear reduction, ratio change, and hypoid action will generate heat. This is why the differential will always run hotter. Also worth noting that I have my sensor mounted on the opposite side of the fill plug in a Fastcooler aluminum sink, which sits low and constantly bathed by fluid, and my temperatures are about the same as what Mike has seen so far. Above all, this is a good thread for those who may not understand what temps a manual transmission will generate.

When I put a temp sensor on my differential I used the fill plug location which obviously sits level with the fluid. Later I changed over to a Mag-hytec which has the sensor mounted directly on the top of the housing.....far from the oil "level" but the normal everyday running temps didnt change.

Lot of truth in that comment dripley..... My 5th wheel is like pulling a sail boat behind me.....with the sails out. Mike your temps sounds totally normal and what you should expect. Sensor placement isnt going to dictate any difference since its most certainly getting splashed and the capacity area isnt that big. I'm glad your temps are doing good too because I was a little fearful of the oil you're using. Thats not saying it was a mistake either but more that I'm curious to see how it holds up for you with the fiber syncros. Keep us posted though because I'm looking to see how well the temps do this summer when you have a heavy trailer behind you. But just to point out again.....as long as you can maintain 4th gear while towing heavy, the odds are that the temps will never get above 180*.

Do keep us all posted.....

Agreed..... 175* is perfectly safe, and I'd be more than happy if that was as hot as it ever got too. But guaranteed it will get hotter when you tow, especially if it gets as hot as you say where you live. For instance, it was around 90* today and my transmission temperatures never got above 140*. But as I've mentioned before, when I tow my trailer in the summer the transmission temps will normally maintain around 160*-170*.....as long as I keep it in 4th gear running on fairly flat highway doing 60 mph. But the moment I have to downshift for s steep enough grade the temps will start to rise because of the gear reduction. And after a long steady climb in 3rd gear in 90* weather I can see the temps run up around 200*. Doesn't mean it will always get that hot but it can if the grade is long enough. And if the weather is hot enough outside (say around 100*-110*) then I've seen my transmission temps remain around 190* while towing on the freeway simply because its so hot outside and it takes too long to cool between small grade differences throughout the drive. I dont enjoy towing in that kind of heat either..... Again, we agree that these are all still safe temperatures. Its when fluid temps get around 225* and higher that I would be seriously concerned as my information what the 4500 can take comes from the older hot shot fellas over the years who found out back then that their 4500's would run as hot as 275* while working. I dont care what temperatures a fluid can withstand.....thats just way too HOT for everything else in the tranny and resulted in those guys having issues. I remember specifically one guy giving up after multiple go-arounds and eventually swapped in a 5600. Not sure how that worked out for him either but I'm sure by the time he got enough miles racked up on it that he moved on to a newer truck.

Glad its working out for you. And your temperature readings are about right. Not much heat comes from these transmissions unless you're towing, whereby you may see the temps get up to around 175*. The higher temps should be only when you tow on grades in 3rd or 5th gear, or drive fast in 5th gear. Its crazy how much heat is generated in the gear reduction value.

Correct, its a regular 3/4" NPT. And yes, a 3/4" to 1/8" reducer will allow for a sensor port too. It also wont matter if the sensor isnt fully submerged while the truck isnt moving either because the temperature difference will be negligible. But no matter because the sensor will always touch fluid while you drive which is when you really care about the temperature anyways. Plus, if you overfill by any amount then the sensor will always be in contact with the fluid. But all that said, I highly suggest that you invest in some Fastcoolers. Not only will the increase in dissipation be worth it but the added two quarts and the port location will be too. I know they're about $200 or so which means you have to decide if you want to spend the money, which would still leave you with the fill plug reducer option. I replaced my fill plug with a sight glass plug. Along those lines, I'm befuddled as to why NV didnt add a drain plug in these transmissions. There's clearly a bung intended for the drain located right under the fill hole but they didnt tap it. Weird.

Very nice job with the grinder..... I have to say, I was expecting something you'd kinda expect to see when hearing someone says " I took a grinder and sawzall to my exhaust". You actually got it just about what the 2nd gen OEM exhaust looks like too. I'm not sure belling the pipe internally would do you much good either because you'd only cause flow restriction and turbulence. The only way you could do what you're thinking is to copy the DM exhaust by cutting back the tip and adding a larger diameter tip and adding bellows instead of sealing it solid around the smaller pipe.