The Ram dealer suggested oil changes for the front and rear when I took it in for the PCM software update, and said 30,000 miles was the interval. I declined, but checked the manual, and it does say 30,000. Whoops, now it's at 38,000. So the front calls for Mopar GL-5 75w-90 AXLE oil, and the rear calls for Mopar 75w-85 GEAR oil. Are they really that different?
Front and rear diff oil
- Thread starter Dave Sherman
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dnewton3
Staff member
No; not substantially different in a way that is likely to manifest into any wear delta.
It's a bit odd that the rear (which takes the brunt of all loads) is actually a lighter grade.
I'd think you could use one grade in both; your choice.
It's a bit odd that the rear (which takes the brunt of all loads) is actually a lighter grade.
I'd think you could use one grade in both; your choice.
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not the same brand, but some on toyota forums state that gear oil on new vehicles need to be replaced first at 5k. The oil comes out nasty. Dont know if its a toyota thing or the equivalent of 3k oil changes
I'm sure it's not a bad idea. However, I dumped my factory fill at 60k and it looked fine.
It is interesting, because mine is the opposite. 75w90 for the rear with a spec that's only available with Mopar fluid and then a normal 75w85 in the front.
FWIW I put HPL 75w90 in both 20k miles ago.
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That ZF rear diff called for 75W-140, then 75W-90. It's still the same rear diff, but FCA kept lowering the viscosoty hoping it helps fuel economy. You can go with 75W-140 in the rear and 75W-85 in the front as the front doesn't do any work. Or do 75W-90 in the rear if you bever tow anything heavy. It won't make a dent in your MPG one way or the other.
I'm surprised the RAM dealet didn't say anything about the transfer case. You should definitively change the fluid in that. Mine came underfilled from the factory by nearly half a quart. You can use Castrol TES 668 ATF in the transfer case, it protects very well, and it's available at NAPA.
The Corporate rear is made by ZF?
I know there were ZF rears in a few cars, Crossfire's I think, but didn't realize it was in the Ram.
Thanks all! Did seem a little odd that they call out different fluids front and rear, but was hoping they weren't so special that garden variety gear oil wouldn't suffice. Weird that the transfer case is a much longer interval (60,000 since I tow), but I should probably check that out too.
Funny! I just got off the phone with my brother who was at Wally stocking up on fluids to drain/fill the diffs, T-case and 8hp45 on his 2019 Ram 1500 classic pentastar.
I suggested 75w90 for the diffs and Maxlife or Castrol Transmax universal for the T-case and AT (let the comments fly LOL). He wants to just do a few dain/fills on the 8spd. I suggested he get a PPE replacement pan or at a minimum, a Doorman replacement. He wants to just D/F given he's at ~60K.
I suggested 75w90 for the diffs and Maxlife or Castrol Transmax universal for the T-case and AT (let the comments fly LOL). He wants to just do a few dain/fills on the 8spd. I suggested he get a PPE replacement pan or at a minimum, a Doorman replacement. He wants to just D/F given he's at ~60K.
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ZF is not as good as Dana.
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Do you have a limited slip diff in the rear? If you don't get yourself two gallons of Delvac 1 75W-90, it's very good gear oil, and it's on the PRI list. @dnewton3 knows more about the PRI list: https://wcm14.sae.org/site/binaries/content/assets/p-r-i-org/qpl/lri-qpl-feb-1-2024-online.xls
My '11 5.7 calls for 75w140 in the rear. Also, I have a BW44 T-case which calls for some stupidly expensive fluid. Mike at Rockland Standard Gear told me that it is so close to ATF that it's not worth using at the cost. He told me to use ATF+4 and that is what they have been using for years. I've been using +4 instead of the $45/qt fluid for 10 years without and issue.
Sure you were checking the fluid level correctly?
I don't think I have the limited slip. I bought it used and there was no mention, and if I use the VIN lookup on the Ram site it just says I have the 3.21 axle with no mention of limited slip.
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We have the 3.21 ZF diff as well, but with limited slip. I use Mobil 1 75W-140 gear oil in it. Valvoline works as well. If you want something better I recommend HPL gear oil. Motul works as well. Oh, AMSOIL Severe Gear, also very good. Any major brand will serve you well, that diff is not hard on oil.
Say, anyone know anything about Ravenol fluids for the transfer case? My searching around looks like this transfer case fluid must be made from the blood of unborn albino rhinoceros and fortified with gold dust since Chrysler wants about $55 per quart for it, and it takes just under two quarts. Blauparts has this Ravenol BW44 fluid for BorgWarner transfer case that's a little more reasonable at $32.95/quart. https://www.blauparts.com/borgwarner-transfer-case-fluid-ravenol-bw44-1l.html
Valvoline squeeze packs for the win. Amsoil has them too. I got Valvoline at Napa on sale last year for like 10-11$ a quart. Bought enough for the 60k and the 120k change.
I'm old school. 75-140 in everything. Ford specs this weird Motorcraft 75-85 or some such malarky stuff that costs a kidney.
OMG I JUST REALIZED I'M PART THICKIE
I think you may have that backwards. My Motor Lubricants Guide shows the opposite. Regardless, I would run a high quality 75W90 in both.
