Hello all,

I have a 1978 Jeep Cherokee and was told that when it was shipped to me that it was leaking a bit (shippers thought it might be transmission fluid). I know that these older Quadratrac FSJ need the TCL-1 for the transfer case (please seeL https://www.quadratec.com/products/5...RoCYCAQAvD_BwE).

However, I was curious what is felt to be a recommended, good quality engine oil and transmission fluid for a 1978 Jeep Cherokee?

Thanks all!

 

Best bet would be to get an owner's or service manual and use the manufacturer recommendations as a starting point. (At least as much as those apply nearly 40 years later. Probably they recommend AMC-branded fluids.)

Generically, I believe a '78 Cherokee (like the Wagoneer) would have an AMC 360 V8 engine and a GM TH400 automatic transmission. I've owned several vehicles with AMC V8s over the years and currently have one with a 360. There is nothing exotic or finicky about these engines and pretty much any good quality motor oil will be fine. The factory would have called for 10W30 or 10W40 viscosity. The block and heads are cast iron and head gaskets not particularly sensitive so any good antifreeze will likewise be OK.

The TH400 transmission uses Dexron fluid. In a 1978 vehicle it is likely to be specified for the power steering as well, but you'd want to verify that.

 

Hello!

Thank you! I appreciate the help and information!

I read through the 1977 Cherokee manual (I could not find the 1978) and the correct Chilton and the '77 manual did note to use either 10W30 or 10W40. I did, though, find online that others are using 15W40 Rotella for the engine oil (https://www.pepboys.com/product/details/522009/00124) so I might try that. Yet I live in a hot and humid climate (30-40F in winter and 90-100F in summer before the heat index) thus do you know if the 15W40 would be okay in an AMC 360 with an Edelbrock 4-barrel carb?

I was also able to find the Dexron transmission fluid at Pep Boys (https://www.pepboys.com/product/details/8545657/00124).

Thanks again!

 

The 15W40 Rotella should do just fine, especially if you're in a climate that doesn't see sub-zero temperatures. It's a diesel oil with higher levels of ZDDP that flat-tappet engines like. (Though from what I've read that is really only an issue for initial cam breakin, and/or if running stiffer-than-stock valve springs in a performance build.)

For transmission fluid I use Wal-Mart "SuperTech" Dexron/Mercon which costs about $11-$12 for a gallon jug. This type is also used in the XJ's AW4 transmission, Chrysler 3-speed Torqueflite transmissions, and quite a few other older vehicles.

 

Hello!

Thank you. This, though, might be an apparent question yet does the Rotella 15W40 still do well in a gasoline based truck or is it better in a diesel if this is a diesel oil?

Thank you again!

 

Congrats on the Cherokee. Those old beasts are fantastic vehicles.

For the best results you really ought to post your questions on one of the FSJ boards.

http://www.ifsja.org/forums/vb/

http://www.fsjnetwork.com/forum/

There are also some very active FSJ groups on Facebook, and generally they don't suffer from the same kind of immaturity you see on other Jeep FB groups. The group "Full Size Jeep (FSJ) Enthusiasts" seems to be the most active, and often people respond to questions there within minutes. Ryan Hart at BJ's Offroad also monitors those groups and will often respond with info on parts availability.

While a few of the folks on this board also have FSJs (I have a '71 Gladiator myself), this board is primarily focused on the XJ, the various Grand Cherokees and the Fiat abomination. Some of these kids are not even aware there was a Cherokee before the XJ. We'll try to help if we can, but the other boards have a much better depth of experience.

 

Rotella is fine in a gasoline engine. Jeepers started using it when people with strokers realized Rotella had the zinc they needed to keep from wiping their camshafts without using additives or paying through the nose for racing oil. From there it has become a Jeep fad. It's optimized for long distance (500+ miles per day) driving and not really for daily drivers, but it won't really hurt anything to use it.

Personally, when I get my Gladiator back on the road, I plan to just use Mobil 1 High Mileage oil. It should work fine for the 360.

It could also have a six cylinder or a 401. On the V8s, you can tell the displacement by looking at the side of the block under the passenger side motor mount bracket. Unless it's a service block, it will have "360" or "401" prominently cast into the block right there.

 

As others here have said, the Rotella will do fine in a gasoline engine. In fact I use Rotella T6 in my XJ since so many people have recommended it here.

Although the 360 is probably the most common V8 engine in those it could be a 401, I remember going over this before and I think that '78 was the last year for the big AMC V8.