Fluids question

[1994IDI]

I've been thinking it may be time to change some of the fluids in the truck in my sig. It has 81,000 original miles, and I'm not sure if the rear end or tranny fluid has ever been changed.

REAR END- How often should I change it? Is it a straight forward procedure, any special considerations? What's the best oil I can put in it from the parts store?

TRANS.- How often should I change the fluid? I do sporadic towing, the heaviest being a 24' pontoon boat and trailer, or a loaded car trailer. But not often. Any good tips to know before changing the fluid, and what fluid does a ZF require?

Also I have been trying to find a magnetic engine oil drain plug for our trucks, and have not been able to find one. Seems my truck requires an M14x1.25. Anyone know where to get a magnetic for these?

Thanks again guys.

 

[OLDBULL8]

Why worry about a magnet for the oil pan, the size is so small it wouldn't show much. Changing the the front and rear diff's is easy, just pull the covers off with a drain pan under them. Clean off the gaskets and the inside's, wipe out as much crud as possible then use brake cleaner to spray inside to clean them. Takes 5 Qts of 85-140 to fill back up 2-1/2 Qts. in each. Use a real thin coat of Hi Temp RTV on the covers and let it set up a couple of hrs. before running it.
Don't know about the ZF, but I think it takes ATF, seen where some guy's use SAE 30 in them for gear rollover noise. Someone will chime in on that I'm sure.

When you drain the engine oil, just run a small pencil magnet thru the oil, if there is a lot of metal in it it will show up then.

 

[Michael Fowler]

You could put a magnet--or several-- on the oil filter.

 

[91f2504x4]

If you have a limited slip rear, make sure to add the limited slip additive. My book says the rear hold 7 pints, wich is 3.5 quarts and half a pint of it should be the limited slip additive. Make sure to use Hypoid gear oil, that is rated for limited slip diffs, if you look on the back of some of the cheaper gear lubes, it will say that they are only suitable for topping off the diff and not for a full refill.


EDIT:
I also recall reading somewhere that you should change differential fluids at least every 24,000 miles or sooner under heavy use.

 

[res0wc18]

uhh, im not sure about you guys but i do complete fluids and filters front to back at least once a year regardless if i have not built up the mileage or not. never had issues this way and my last f350 got 339k mile on it before it gave issues.

 

[Agnem]

Rears usually take 80-90 weight gear oil, with a limited slip additive if needed. ZF's require Mercon (not Mercon V which is more readily available). However, those of use with SMF's will use streight 30 weight non-detergent motor oil or some other funky concoction.

 

[RLDSL]

Without knowing the inventory available at your local parts store, it's pretty hard to say what would be best , but a safe bet is always a synthetic if you are looking for better lubrication. Even a cheap synthetic is better than no synthetic at all in most cases. Exception being the rotella 5w- 40 which is just too darn light for these engines in most cases and burns like crazy. You;d be better off with good old Delo 15w 40
ZF calls for ATF, Dexron III. Motor oil is not a good substitute. If you want to go heavier, you can get 30 and 50 wt ATF which are suitable for manual shift transmissions ( regular ATF is 20 wt )

It looks like the diffs call for a 75w-90 on that year with 4 ounces of limited slip friction modifier needed if you have a limited slip rear

Don't forget a good synthetic base grease for the ujoints and steering linkages

 

[91crew]

Is a friction modifier still needed in the rear diff if you have amsoil synthetic in there? I thought I heard that synthetic oils take care of the friction modifying.

 

[DragRag]

If you have a worn rear diff clutch reducing the modifier will help it grab a bit harder to do its job the way it used to. Sometimes some leave it out all together just to get it working again.

 

[RLDSL]

Is a friction modifier still needed in the rear diff if you have amsoil synthetic in there? I thought I heard that synthetic oils take care of the friction modifying.

With the Amsoil a friction modifier is generally not needed unless chattering is experienced. In that case you can add some of the Amsoil Slip lock friction modifier to it. It's pretty rare to get one that chatters with the Amsoil. Usually only high performance builds where you run into that.

 

[Goofyexponent]

http://www.off-road.com/trucks4x4/article/articleDetail.jsp?id=199178 I wonder how these work. They claim to capture and hold metal particles inside the oil filter...no mess to make. I wonder how well the magnets hold themselves onto the filters?

 

[RLDSL]

http://www.off-road.com/trucks4x4/article/articleDetail.jsp?id=199178 I wonder how these work. They claim to capture and hold metal particles inside the oil filter...no mess to make. I wonder how well the magnets hold themselves onto the filters?

No reason that thing wouldn't do a decent job of catching small metallic particles. Surely an easy way to go about catching some of the small stuff. Keep in mind, it is trying to grab particles out of the flow path under pressure so a lot is going to get away from it, unlike a bypass filter, where the oil has to fight it's way through the filter media so any particles have no choice but to be trapped .

 

[Goofyexponent]

If you had two of these things on a powerstoke filter on the IDI it might not do too bad. Any improvement is good in my eyes.

if a powerstroke oil filter will fit into and IDI pan check this out http://cgi.ebay.ca/Magnetic-Oil-Dra...s?hash=item4832a811ac&_trksid=p3286.m20.l1116

 

[1994IDI]

Ok been doing some searching around, per the parts store, both of my differentials (10.25 and dana 50) and the ZF 5 speed, require synthetics, or you could be looking at costly repairs.. can anyone atest to this?

 

[res0wc18]

uhh, never heard of that besides that my 97 rear end needs 75w140 synthetic with limited slip.

Ive always just kept clean and full fluids in all my boxes and never had any problems. Synthetics are the way to go on low mile or new stuff, but im not one to start running it in a rig with 100k plus miles no matter what they say the molecules on synthetics is smaller, so that means to me that it has the chance to leak with less effort.