AX15 Towing and Differential Oils

97 XJ, 4.0L, AX15, 2WD

I'm confused about gear oil for the rear differential. I have the 8.25 axle. The owner's manual says to use 75w/140 for towing applications and 75w/90 for normal applications. The FSM says for the 8.25 axle to use 80w/90 with no mention of higher weights. Is this is because models with this axle did not have tow packages available? Basically, what I need to know is if I am going to tow things, what weight should I use? I'm looking at Redline, because I'm ordering some MT90 for the tranny anyway.

This is a related question. I have a pop-up camper with the following specs:

Unloaded Vehicle Weight- 2300
GVWR- 3070
tongue weight- 350lb
Gross Axle Weight- 2720

It has brakes. From all the posts I've read, it appears I can tow more than the class 1 rating specified in the owner's manual for an XJ with an AX15. Can I tow this camper without putting too much strain on my transmission? I have the 3.07 differential gearing, as indicated by the tag on the housing.

My fiancee just bought this camper and has towed it with her Santa Fe, and now wants me to tow it with my beloved Jeep. I don't want to do anything to reduce its life expectancy.

I appreciate any responses.

sgt

75w/140 synthetic for towing and off road use.

Follow the recommendations of the owners manual concerning towing capacity. ( I think the ratings are a bit low for a 5 speed ) Any extra stain will be mostly on the clutch. Use a Class III hitch.

x2 on the 75w140 for towing.

I'm not sure if the AX15 XJs were ever offered with a factory tow package, or maybe it was only for a short time.

I believe the only issue would be premature clutch failure. The AX15 1st gear is a little "tall" and with the 3.07 gears combo there is more stress on the clutch. Just my humble opinion.

As you have a 2wd XJ, why don't you have your GF buy you a set of 3.73s?

It's unlikely that the AX-15 was offered with a factory tow package - simply because tow packages tend to be built around automatics (most people barely know how to drive a stick anyhow.)

Make sure you use GL-3 in your AX-15 if you're going to tow - since the sulphur-based EP lubes in GL-4 and GL-5 are antagonistic to the yellow metal (bronze) synchroniser rings. And moreso at elevated temperatures (like with towing.)

The use of 75W-140 in the rear axle when towing would be correct - it's a common enough application (and you'll want GL-5 in the axle. Make sure to also use LSD FM if you have limited slip as well - or your clutches will start to chatter rather quickly!) You should need to make no changes up front, unless you plan to tow in 4WD (80W-90 or 75W-90 work fine to keep things lubed up there. 75W-140 if you plan on towing in 4WD - since the axle gearing is biased slightly toward the front anyhow for better control.)

Towing with 3.07 is something you will want to be mindful of - it's doable, but you'll want to go fairly easy on takeoffs (once you get to freeway cruising speeds, you'll be fine. Make sure your brakes are properly slaved.) If you're going to tow this a great deal, consider regearing - and tailor your gear ratio to whatever size tyres you're going to run. Note that you're likely to want to change at least one carrier, since you'll be crossing a carrier break (the gear ratios of the AX-15 make 3.73 and better look good.) Better axle gearing will make for greater clutch longevity, since you won't be clobbering it when you take off.

However, I'll definitely say that the XJ - at least the early ones - are seriously underrated in their towing capacities. At least, to a careful driver. I drove my 89 back ATL-SJC with a 3000# box trailer without any trouble, and my 87 made several LTL trips with upwards of 3500# of scrap metal without any trouble after a salvage job I had to do. So, I like to think I've got a pretty good idea of what I can do with them now (and how I can improve them later, which I'd like to do with my 88.) I'll grant that both of the XJs mentioned first had the AW4; but the AX-15, from what I've seen, is actually a fairly robust gearbox for what it is.

Thanks for the great replies everyone. Couple o' things:

5-90 says: "Make sure you use GL-3 in your AX-15 if you're going to tow - since the sulphur-based EP lubes in GL-4 and GL-5 are antagonistic to the yellow metal (bronze) synchroniser rings. And moreso at elevated temperatures (like with towing.)"

The consensus I've gotten from previous posts is Redline MT-90 is superb, even though it is GL-4. Is it still okay for higher heat apps like towing? From previous posts, I'm getting that it has some additive that causes it not to eat the synchronizer rings.

As far as gearing and tire size, I'm running Dueler AT Revo 225/75/15. I'm guessing a street tire would be better for towing? I won't be towing this camper often, however. We camp about 5 times a year, and usually within 60 miles of my home.

Joe Peters says: "The AX15 1st gear is a little "tall" and with the 3.07 gears combo there is more stress on the clutch. Just my humble opinion."

They are indeed tall. On the street it's great, because this baby flies!

The gross vehicle weight for this camper is 2300 pounds. We can definitely do separate vehicles and load the other vehicle with gear and people to take load off the Jeep. I guess I'll just see how it goes and go from there.

Thanks again for the replies. Very helpful.

sgt

mt-90 is fine to use because its safe on yellow metals.

personally im switching to mobil 1 10w30 in my 5spd(ba-10).

as for the gearing, you should be fine as long as you dont go larger than stock size tires.

You don't mention what size tires you have. If you're running tires that are taller than stock, REGEAR.

I towed a Coleman Santa Fe behind my 94 XJ from Chicago to Moab 3 times, twice with 31x10.50s and 4.10 gears, once with 33x12.50s and 4.10 gears. Yes, it's an AX15 5spd. No real problems, although it definitely did struggle a bit in the Rockies with the 33" tires.

The big problem with XJs and towing really isn't go, but stop. Make sure you've got a good set of brakes on that camper. I greatly prefer electrics (with a Tekonsha Prodigy controller, but that's a different debate) over surge brakes.

Oil? I've been running Redline MT90 in my AX15 for years, and especially in cold weather, it's one of the best things I did. And 75w-140 in the diffs is probably a good idea as well.

ChiXJeff:

I'm running Dueler AT Revo 225/75/15. As close to stock as I could get when I bought them a couple of years ago. This camper is also a Coleman, but I forget the model. Late model with a large box. It does have electric brakes. I have also been looking at the Prodigy controller.

sgt

You're not going to win any races, and as long as you don't slip, or ride, the clutch, you should be in good shape. You definitely want to watch the tachometer, and make sure that the speed rises when the tach does.

Get the Prodigy, or the newest one, the P3. I ran an earlier Tekonsha in my XJ that had to be balanced when the vehicle pitch changed. No real problem, but I did have to remember to do it. The Prodigy and P3 don't require balancing, just dial in the voltage, and the boost feature, and forget it. FWIW, Dad has a Prodigy in his Dodge 3500 for a heavy gooseneck. I've personally scaled the rig at over 36,000 lbs, and the Prodigy worked very well. Dialing in the voltage can't be any easier, swing the lever over, and read the digits.

I've been using my stock AX-15/8.25 combo to pull routinely. The only thing I will say about it is, it is a slow machine but capable. I pulled a 1999 Civic with mine from the West Virginia area near Pittsburgh to Raleigh, NC and it did fine even in the mountains (in a snow storm in western Maryland mountains as well). Did a lot of driving in 3rd gear on that trip, but the engine held up fine, no overheating or damage. My Jeeps has 285K, and I tow regularly. Actually the guy I got it from was using as a landscaping vehicle and was pulling a 2500lb trailer with it everyday. I put a new clutch in soon after I bought it (due to another issue with the clutch linkage inside the bellhousing) and the old clutch was still in pretty decent shape and there weren't many stress fissures in the flywheel either. I was surprised by the little trucks ability. I did switch to the 75W140 in the rear prior to doing any towing personally, but the previous owner had not and I could not see any damage when I had the diff cover off, and he was towing on a daily basis with the truck for 2 years.

That's a funny coincidence nblanton. My dd is a '95 Civic and I live in Raleigh. My Jeep is still a baby with only 134K. I plan to keep her for a long time.

I actually have one more question regarding the differential fluid. I haven't determined yet if I have a limited slip. I'm waiting on a build sheet or if that doesn't arrive soon enough I'm going to jack up the rear end and spin the wheels. I'm guessing I don't, since this is a 97 SE trimline. But, say I don't have limited slip and I put a fluid in that *has* the friction modifiers. Is there a disadvantage to that? From reading Redline's site, where they sell a 75w/140 with and without the modifiers already in it, they seem to imply there is an advantage to *not* using the modifier in a vehicle that doesn't require it. They don't go into great detail about it.

thanks again,
sgt

sgtpeeper said:

That's a funny coincidence nblanton. My dd is a '95 Civic and I live in Raleigh. My Jeep is still a baby with only 134K. I plan to keep her for a long time.

I actually have one more question regarding the differential fluid. I haven't determined yet if I have a limited slip. I'm waiting on a build sheet or if that doesn't arrive soon enough I'm going to jack up the rear end and spin the wheels. I'm guessing I don't, since this is a 97 SE trimline. But, say I don't have limited slip and I put a fluid in that *has* the friction modifiers. Is there a disadvantage to that? From reading Redline's site, where they sell a 75w/140 with and without the modifiers already in it, they seem to imply there is an advantage to *not* using the modifier in a vehicle that doesn't require it. They don't go into great detail about it.

thanks again,
sgt

Click to expand...

royal purple already has the modifier in their gear lube.

look for a sticker in the glove box. if you have the sticker, it will indicate whether you have traction control and a friction modifier needs to be added.

best to look into the diff housing to see if it has lsd. if you have lsd and its worn out, it may appear as you dont when you spin the tires.

Thanks for the tip. No sticker in the glove box. However, there is a sticker that circles the axle near the right rear tire. Not only does it say 8.25, chrysler, and some other stuff as I recall, it also says "OPEN". Anyone recognize this sticker? Again, this is a 97 XJ. I'm guessing by the "OPEN" this sticker indicates it is not limited slip.

That means exactly what you think it means. It's an open rearend. It should look like this when you pull the diff cover off.

Just imagine a big gear ring bolted to the flange on the right side and caps over the two side bearings.

Sweet! Thanks for help!

I use/recommend Amsoil SevereGear 75W/140 for the rear and 75W/90 for front axle.