PML or Mag-Hytec Differential Covers

[RUSSELL5000]

I didn't really see a discussion of this; perhaps I have missed it.

I have read quite a bit on the forum and in the magazine about the Mag-Hytec differential covers (and transmission pans). It is clear the Mag-Hytec line is highly thought of. I have no experience of my own.

My truck just clicked over 15,000 miles and I see from the maintenance schedule that it is time to change the front and rear differential fluids (my truck is pretty much just used for highway driving, and mostly towing a trailer of some type when it is doing that).

I note that there is a roughly a $100 difference in price between the PML and Mag-Hytec differential covers in the Geno's catalog. I assume the purpose of replacing the stock cover is to: (1) obtain a drain plug to make future changes easier, (2) obtain a port to install a temperature sensor, (3) obtain additional fluid capacity, and (4) obtain cooling through a finned cover.

My thinking at this point is that the drain plug is of the greatest value to me, and am questioning whether the additional $200 or so is worth it for the Mag-Hytec covers (two covers, front and rear).

Am I missing something in this analysis?

Thanks!

 

[Bug Out]

Your on target. Mag Hytecs are the "Pretty ones" and are very well made. That being said, I read a article some time ago that took some of their "bling" away as the paint actually retains more heat then a bare aluminum pan, which dissipates heat better. ie thats probably the reason the factory did not use them on the max tow trucks.

Your towing fairly light in weight for what your truck can really tow without any needed fancy pans etc. Pick up a infared heat gun at Harbor freight (30-40$) and check both rear end and transmission pans for temps towing and empty before you buy the pans. You'll find a better use for your cash on something else. As your other post stated, transmission temps in 180 range??? thats cold as far as transmission oil is concerned before you need extra cooling. Unless you like pretty covers etc. Rear end is probably 150-190?. If I had to do it again, I would have stayed stock and spent that $500 on something else. JMHO

 

[seafish]

Save some money...you don't really need the increased capacity in the front as it doesn"t really heat up unless you use 4wd ALL the time...what I did at the first fluid change was to remove the cover and then find just the right spot at the bottom of the front diff to drill a hole for a 1/4" primary case oil drain plug from a Harley motorcycle. I actually did ithe same thing at the rear diff, but have since swapped the rear to a MagHytech pan that I got used. See these posts--

https://www.turbodieselregister.com/threads/236707-Max-Tow-Diff-Cover?p=2287346#post2287346

https://www.turbodieselregister.com...-Plug-for-differentials?p=2148060#post2148060

Sorry no pics, but it has been workign GREAT for years and several diff oil changes. I can find you the part # for the HD plug if you want me to.

Now the rear diff IS another question as it IS helpful to have both a drain plug, a dipstick as well as increased capacity. I was able to buy a Mag Hytech barely used for $175 from a member on another forum and it IS a magnificent piece of craftsmanship. I DON'T really buy the part of the paint holding in more heat then an unpainted diff cover, though the PML DOES have more fins and might offer SLIGHTLY better cooling then the Mag Hytech, but someone would have to a side by side somparoson on the same truck to know for sure.

Just my .02

 

[Cummins12V98]

I could be wrong but I think the MagHytec holds more fluid. I would not waste the money on the front.

 

[Bug Out]

Cummins12V98, your right. It holds more oil. I checked the stock cover on the 13' several times while towing and it was running 160-185. I'm at the same temps now with the Mag hytec. Now on my 2005 dually, it made a difference of 20+ degrees, but nothing noticeable with the 2013.

I dont know if AAM is doing a better job machining or set ups in their rear end units now then back in 05, but the 13 runs cooler. Might have something to do with 4:10 vs 3:42?? Dont know. Small footnote. Bought the Mag Hytec rear cover with viewing glass and just saw minor oil seepage today the viewing glass....

 

[mpaulson]

I read once somewhere that claimed that the Mag cover which claims to increase the capacity more than the competition and only does so by raising the fill level placing the fill plug higher than the competition. Just a though. On my last truck I had the AFE one with the sight glass on the side and at the top of a long climb with the trailer and with my brother law following me with basically the same RV but 2' longer, I jumped out and used my infrared temp gun and shot both diffs and they were within 5 degrees. Mine with the cover was warmer (with the cover)but not by anything to prove any concern. Save your money in my honest opinion.

 

[RVTRKN]

Might have something to do with 4:10 vs 3:42?? Dont know.

Thats my argument about the 3:42 vrs 3:73 vrs 4:10. Those 3:42's have to be generating much more heat and will wear much faster. My vote is for the Mag Hytec, and have plans to install one after my project to install my trans cooler and pump, to cool my G56. I have spent a lot of cash on the cooling system, so the Mag Hytec cover will have to wait.

 

[lawdog1]

I have had the Magtech trans pan and rear diff on both of my CTD's. I agree with the comments about the front diff, I don't use the 4wd near enough to justify the expense. ....when it comes to justifying the expense, I can't say I have seen any "problem" with the stock trans pan or rear diff cover, nor have I ever checked rear diff temps when towing (stock or w/ the MagHytec.) I like the extra capacity, connection for temp probes, drain plug, dipstick, etc. as previously mentioned. What I really like is the look for the rear diff cover. I personally would not get the cover with the sight window....my thoughts on that are "why" and "a problem waiting for the right time to commence ruining your day."

 

[BarryG]

I have had mag hytec covers on my truck for approx. 300k so far. They have had no issues at all. The magnetized dipstick is nice as is the drain plug and extra capacity. The oring seal is also nice. I have only dropped my covers a few times over the last 14 years but it is nice to pop it off and be able to put it back on without scraping off gasket material or silicone sealer. Is it worth the extra $ well the drain plug alone is worth something but don't know that it is worth $200+. One thing nice about the mag cover drain plug is that it is on the bottom, not near the bottom (like if you made one in the stock cover) so when you drain it you get it all and that along with the magnetized dipstick you get the vast majority of fluid and junk out. If you drive enough that you should change your fluid yearly like I did when it was my daily driver those convenience's sure are nice. Would I buy them again maybe but then again maybe not. They're definitely a high quality piece and look good to boot. Now I don't tow real heavy so fwiw on 100+ deg ambient temps in hilly terrain towing at 70 mph with maybe 9k I have rarely seen temps above 200 deg in the rear. I put one on the front for the same reasons and as mentioned previously unless you use 4wd for extended periods probably not needed. However for me I frequently travel across the state in the winter time here and there have been many times where I have been in 4wd for 300 miles at a time due to snowstorms/road conditions.

 

[MattandLana]

... unless you use 4wd ALL the time...

... front diff, I don't use the 4wd near enough to justify the expense....

... unless you use 4wd for extended periods

But unless you have manual disconnect hubs, the front diff will be turning just as much in 2WD as in 4WD, won't it?

 

[RVTRKN]

But the front diff is floating when its without a load, it will generate some heat and some wear, but there is no pressure on the gears.

 

[Joseph Donnelly]

Front axle disconnect was re-introduced in the 2013 3500s, now using an electrical instead of vacuum control (as was the case in the '90s), so the front isn't loaded, although the one axle turns and that turns the spider gears, and slowly can turn the driveshaft. Actually that is a good thing, because prolonged use in 2WD can wear the splines "crooked" in the front driveshaft if it has a slip yoke. That happened with my 1980 (before I bought it used), and the inside of the pumpkin had rust on the top from lube not getting splashed around.

As for heat and wear, decades of car experience with 3.42 vs. 4.10 suggests that our Rams should not see any problems with 3.42. Eventually we may collect some data based on actual use.

 

[CUMMINZ]

 

[RUSSELL5000]

Thanks, guys.

I have a follow-up question, which follows the discussion above regarding the front differential. I use the four-wheel for a short time when I am backing up the trailer - I really like being able to just barely inch along so everything happens nice and slow while I back in to where I want to be. Should I even bother to change that fluid?

Also, it seems to me that 15,000 miles is a really short interval. I would say 6,000 of those miles are towing my travel trailer or the boy scout trailer and 7,000 are highway miles unloaded. The other 2,000 are running around to get on the road. Should I really need a change already?

Cumminz, I like your pictures. I already have the PML transmission pan - I monitor my transmission fluid temperatures and they are quite low. The stock pan may have worked just was well, but t seems to me you can't go wrong with more fluid that is cooler.

Thanks!

 

[MSicotte]

I just bought the Max Tow aluminum finned differential cover as a kit with new reusable gasket and all new bolts for $142 including tax from my dealership. It holds 4 litres of fluid. (Canadian eh)

 

[Cummins12V98]

I just changed my rear diff fluid it came out golden clear at 48K on the lube. Had a bout 1/8" of fines on the drain plug. Have the MagHytec cover and use AMZ/OIL 75/110.

 

[RUSSELL5000]

I am gearing up to change my differential fluids and looking at the new cover.

I don't think there have been any rear axle changes going from the 2012 to 2015 model years has there? I talked to the parts guy at the dealer and he said the finned aluminum cover was roughly $90. He was not sure whether it would fit, however. Seems to me it would. Does anyone know?

I am thinking of going this way, as about 1/2 the cost of even the PML cover.

Thanks!!

 

[Bug Out]

Thats a great price by the way.. If the dealer is selling finned covers for $90, I paid 100 too much.I bought a PML for the first time . As far as I can tell, all AAM rears are the same , but I'm not positive about the 38K GCVWR rear axle on the 3500. I believe I read that the outter housing/cover are the same, but the inners are different. The regular up to 30K GCVWR are the same.

 

[gsbrockman]

I am gearing up to change my differential fluids and looking at the new cover.

I don't think there have been any rear axle changes going from the 2012 to 2015 model years has there? I talked to the parts guy at the dealer and he said the finned aluminum cover was roughly $90. He was not sure whether it would fit, however. Seems to me it would. Does anyone know?

I am thinking of going this way, as about 1/2 the cost of even the PML cover.

Thanks!!

If you're referring to the OEM style aluminum cover that was utilized on the 2013 & up Aisin 3500 DRW trucks, it will fit on your leaf-sprung 2500 without any problems.

It will fit on 2014 & up 2500's with coil suspension......with a little grinding of the cover to accommodate the sway bar.

The new cover adds no additional capacity on my 2014 3500 with 11.8 / 300mm ring & pinion.

http://www.cumminsforum.com/forum/2...90-11-8-300mm-aam-rear-axle-fluid-change.html

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The kit part number (cover, hardware, and new, re-sealable gasket) is 68149259AC.

 

[RUSSELL5000]

Talked to the parts guy at the dealer. He found the part number - he said the price for the kit is $107. He also said that his system showed "backordered - unavailable."

gsbrockman - I note on your thread regarding the fluid change that you were doing the first change at roughly 37,000 miles. I see the following from the maintenance section of the user guide my truck came with:

"Inspect the front (4x4) and rear axle fluid, change if using your vehicle for police, taxi, fleet, off-road or frequent trailer towing." The interval listed is every 12 months or 15,000 miles.

Does this mean anything? There is also a line to lubricate the outer tie-rod ends - although they are sealed and there is nothing to lubricate. Is this another instance of someone not reading the manual and keeping up to date?

Thanks!