Aisin VS 68RFE

[apgambino]

The 2500 doesn't have the Aisin, right?

From what I read, it is the 3500, Aisin, and the 3:42 gears that work well.

Correct

2015 3500 SRW 4x4 MegaCab Laramie Aisin

 

[SnoKing]

I never liked the 3:42 before and after the scramble. It's puts the CTD below its optimum RPM for power and torque. Everyone likes the 3:42, and that's OK, BUT I'LL NEVER BUY ONE WITH 3:42.

So you run in the next lower gear and you are in the optimum RPM for power and torque. Save 6th for bob tailing! What is the mystery about doing that. I tow in 5th all the time. Truck in Tow Haul will not shift to 6th gear until 65 MPH anyway. At 24K+ the only time I ran that fast was on I-10 between Palm Springs and Phoenix with my smaller trailer.

 

[RVTRKN]

I would trust the Aisin more with 3:42 gears, but 4:10's in a 6spd auto is pretty nice, in that it allows you to drop your RPM's into the sweet spot for a Cummins. Unlike the 48re that would have you screaming up a grade. I wonder what the temperature difference is with the 3:42 vrs the 3:73 vrs the 4:10, in the rear differential. I had to install my own transmission cooler in my G56 because it runs hot @ 250*+ if I don't.

 

[SnoKing]

So this might help some understand why the Aisin works well tow with 3:42 gears
-----47/48RE----Aisin
1st- 2.45:1-----3.75:1
2nd 1.45:1-----2.00:1
3rd 1.00:1-----1.34:1
4th 0.69:1-----1.00:1
5th------------- 0.77:1
6th------------- 0.63:1
Rev 2.21:1-----3.54:1

 

[Cummins12V98]

I would trust the Aisin more with 3:42 gears, but 4:10's in a 6spd auto is pretty nice, in that it allows you to drop your RPM's into the sweet spot for a Cummins. Unlike the 48re that would have you screaming up a grade. I wonder what the temperature difference is with the 3:42 vrs the 3:73 vrs the 4:10, in the rear differential. I had to install my own transmission cooler in my G56 because it runs hot @ 250*+ if I don't.

Here is my 11 HO Dually 3.42's with 60K with 1/2 of the miles towing 28-29K combined. Ran AMZ/OIL 75-110 SevereGear, the lube had around 50K on it. I was running a MagHytec cover. I am guessing it ran cool as the fluid came out golden brown and the machining is still visible on the gears.

 

[18Dodger18]

C12V98; A friend gave me a tip which I thot was worth passin' on:
He says every time he sprays off his rig, he sprays the fins on his Mag-Hytec to keep'em clean from road crap and thus keep'em cooler.. maybe ??

 

[Cummins12V98]

C12V98; A friend gave me a tip which I thot was worth passin' on:
He says every time he sprays off his rig, he sprays the fins on his Mag-Hytec to keep'em clean from road crap and thus keep'em cooler.. maybe ??

That's a good idea!!!

 

[Newsa]

Wondering if letting a slowly leaking rear axle seal go will contribute to this. Is checking the fluid every 15,000 miles enough?

 

[Kirwin]

I wouldn't do that. Leakage is an indication of seal failure. Weepage on the other hand may be acceptable, but warrants close watching. The pinion seal has weeped on several of my trucks, but it doesn't form a drip, so I monitor it but for the most part ignore it.

Wondering if letting a slowly leaking rear axle seal go will contribute to this. Is checking the fluid every 15,000 miles enough?

 

[Newsa]

I wouldn't do that. Leakage is an indication of seal failure. Weepage on the other hand may be acceptable, but warrants close watching. The pinion seal has weeped on several of my trucks, but it doesn't form a drip, so I monitor it but for the most part ignore it.

Actually, i was thinking of weepage. I see no drip or evidence on the driveway. Just slight discoloration on one of the wheel backing plate.

Changed the fluid at 16,000 miles. Now at 30,500 miles, I will change the fluid again, this month.

 

[kthaxton]

2014 2500 with 3:42 scrambled at 14K miles, and thats not on my computer, thats on Dodges computors. Also Dodge had to buy back the truck for other unrelated issues, So I can speak from experiance. My next CTD will have the 4:10's.

Your "experience" is based on some kind of (likely) unrelated failure. Your experience is NOT based on a perfectly functioning truck with 3.42's.

If what you believe were reality, we all would have failed 3.42 diffs.

 

[RVTRKN]

To each his own, I'll only buy 4:10 gears, my 07.5 has 3:73, and I wished I had upgraded to the 4:10 after towing heavy.

 

[kthaxton]

Yes, of course, to each his own.....but to constantly preach that 3.42's are the cause of your problem is misleading.

 

[Cummins12V98]

Why was I able to tow 28-29K combined West Coast with my measly 350/800 HO Dually with 3.42's??? Because in reality it was a 4.10 in 5th.

New 385/900 with AISIN and 3.42's is a serious towing machine per RAM up to 28-29K range.

If my RV was 5K lighter I would be running 3.42's for sure. Also I would be getting 14-15 running around instead of 12-13mpg.

 

[RVTRKN]

I said I lost the rear diff, as far as I can recollect, I never said 3:42 was the cause, but it did fail in a spectacular fashion. It was the first Ram my Boss purchased and will be his last, it had so many issues, he sued for the full purchase price, including the cost of the service bed for $60K combined, and won the case. Again I will not purchase a truck with 3:42.

 

[RVTRKN]

Why was I able to tow 28-29K combined West Coast with my measly 350/800 HO Dually with 3.42's??? Because in reality it was a 4.10 in 5th.

New 385/900 with AISIN and 3.42's is a serious towing machine per RAM up to 28-29K range.

If my RV was 5K lighter I would be running 3.42's for sure. Also I would be getting 14-15 running around instead of 12-13mpg.

I have a 3500 for capability, not MPG.

 

[kthaxton]

But the problem is you keep relating the gear ratio as the cause of the many problems you had.
Correlation is not causation, otherwise..............

 

[RVTRKN]

Just convince someone else the 3:42 is OK. You can post all the positive info you want, and it won't convince me. If the capability with 3:42 is 30K, then with 4:10 its 35K. I wont be buying a truck soon anyway so its a mute point. I don't care why my 3:42 failed, just know it did, and the whole housing, and related parts had to be rebuilt. I don't understand why they rebuilt it vrs replace the assembly, but IT DID FAIL. This will be my last post on this subject.

 

[SnoKing]

Just convince someone else the 3:42 is OK. You can post all the positive info you want, and it won't convince me. If the capability with 3:42 is 30K, then with 4:10 its 35K. I wont be buying a truck soon anyway so its a mute point. I don't care why my 3:42 failed, just know it did, and the whole housing, and related parts had to be rebuilt. I don't understand why they rebuilt it vrs replace the assembly, but IT DID FAIL. This will be my last post on this subject.

Great! Thanks for your input! Snoking

 

[kthaxton]

You could just as logically say your diff failed because the axle housing was painted black....and then tell everyone else that black axle housings cause ring and pinion failures.