Ford switch 80w-90 to 75w-140 synthetic. Why?

[Colt45ws]

Yes, it could be reclassified as a 110 depending on how far into the scale it was made. 140, eh, no, not really. The bottom spec for a 140 remained the same.
I would use a Synthetic 75W110 or 140 in those older axles. UnDummy linked to some of the 110s available and 75W140 is pretty common. Either would work fine and there is not really any reason not to. Maybe a slight loss in fuel economy.

 

[j_mac]

Wonder if there is a difference in the 8.8 ring and pinions, spider gears, etc between the old 5.0's and early 4.6's also including your Crown Vic that took 80W-90 versus the later 8.8's that now specify 75W-140. I mean like a difference in the heat treating or whatever.

 

[Colt45ws]

No.
Though, there was a run of early 2003 Crown Vic axle shatfs that missed a heat treatment stage. The axles were toast by about 20-30k no matter what oil was in them.

 

[Jim Allen]

Colton, do you run a diff temp gauge? Based on what I know about 8.8s in cars, they don't run hot enough to need a 110 or a 140 grade oil. I think in terms of friction, the heavier syns may be similar to a lighter mineral but think of the fuel savings with a syn 90? Lubrizol has been experimenting with some special lighter-than-normal oils designed to reduce friction but still offers the necessary protection. Kinda like that new 80 grade Toyota oil.

 

[Colt45ws]

No, I dont.
Its on "the list" though.
Based on what youve said about the Truetrac I want to install, I will probably go to a 90, if I can find one that is compatible.

 

[Colt45ws]

Do you know how much impact gear ratios have on temp?
My car has a 2.73 gear set while the CVPIs run 3.27 or 3.55. The Mustang is probably a 3.27 or 3.55 as well. Could this be the reason?

 

[Jim Allen]

High gears like yours run cooler than low gears. I've not seen any exact data, but I once asked the question of an axle engineer and the "guesstimate" he gave me was about 10 degrees per full ratio (e.g. 3.0:1 vs 4.0:1) in a similar application (weight, rolling resistance & load). The taller ratio have more tooth contact so the load is spread over more area and a bit less friction is generation in the hypoid action.

 

[Colt45ws]

Thats..insignificant. Even if I went to a 4.10 Id probably have trouble keeping control of enough variables to actually test for and see the difference in The Real World.
It must be purely an expected use question for why some axles get the "75W140 synthetic" tag and others dont even within essentially the same model and model year.

 

[j_mac]

What I can add about the 8.8 from extensive street use and extensive drag racing use is that the early units are basically indestructible. We regularly supercharged and nitrous injected these cars up to 600 hp and used slicks at the track. The only problem I've ever seen were pinion seals leaking which is not uncommon in high mileage 8.8's.
My experience is with the old 5 Liter cars. I've done alot of work on some of the newer ones, and have friends that have had them and I myself have a '99 model. It has 150k+ on it and a pinion seal that leaked but "resealed" itself somehow. It has a grinding noise in the rear end. Its been doing it for 60K miles. I'm not sure if its a bearing noise or something in the diff making it. Its a common noise that started in 1996 when they started making alot of the stuff on these cars in Mexico. I've heard this same grinding noise on MANY '96-'99 cars. It may be a problem on later ones too, but I have limited experience with those. When the noise started on my '99 I went and bought all the bearings, seals and a crush collar to rebuild the rear. I made sure the bearings were Timken brand and everything said "Made in USA" or "Made in Japan." But I never got around to disassembling the rear. The noise never worsened so I've just lived with it for 60k miles. This car is just basic transportation. I'm not too worried about it.
Anyone have any idea what the grinding noise is in the post-'96 rear ends?
I know Ford started having Tremec make their transmissions in Mexico starting in model year 1996, and for some reason I remember seeing some evidence that the components in the rear ends were made there too IIRC.
My girlfriend had a 2002 Ford Focus SVT. The rare high performance model. What a piece of junk that thing was. It was assembled/made in Mexico. That car slowly fell apart before our very eyes. It had 25K on it when she bought it and only 40 or 50K when we got rid of it.
Any input on the "Mexican factor" in the 8.8's, etc would be appreciated. Maybe I'm wrong. Is it something else that led to this endemic grinding noise?

 

[Jim Allen]

Originally Posted By: Colt45ws
Thats..insignificant. Even if I went to a 4.10 Id probably have trouble keeping control of enough variables to actually test for and see the difference in The Real World.
It must be purely an expected use question for why some axles get the "75W140 synthetic" tag and others dont even within essentially the same model and model year.


Yeah, I tried to measure the difference myself and couldn't really sort out the differences (I was going from 3.08 to 4.10 in a GM 8.5). BUT, it does add to the total. I've looking at things mostly from the truck and hauling aspects. What little data I've seen on cars indicates that they run pretty cool for the most part. I know my pickups empty run pretty cool.

The closest personal look I've had is with my old Blazer with 3.08 gears. It was about the bulk of a large older car, perhaps pushing a bit more air. According to my notes from back in the '90s, it ran at about 180 in 90 degree temps going down the highway at 70-75. That was with a dino oil... I think a Valvoline 80W90.

 

[Jim Allen]

jmac- I don't believe the axles were ever made in Mexico. AFAIK, they were all Sterling or Visteon products, made there in Sterling Hts, MI. That's more than just a guess on my part, having dealt with the Visteon people in the past and gotten some product materials. They indicated at the time that all Ford beam axle were made by them.

For the most part, Ford axles have been generally better than many others built for the "Big Three." I think AAM is at the top-o-the-heap these days, but not by a lot. All of them, Dana Spicer, GM Saginaw (later AAM) Sterling Axle DIv (later Visteon and now Sterling again I think) and CHrysler's Detroit Gear & Axle have all had their ups and downs.

What I like most about Ford axles is that they mostly use a SAE1050 high carbon steel in their shafts, which is a good 20 percent stronger than the the 1030/1035/1040 often used. You even see some SAE1541 shafts in Ford axles.

Some years back I sent in a 8.8 Explorer axle shaft in for destructive tests. It was to be broken on a machine with a 6000+ lbs-ft capacity. It was routinely breaking Dana 30 and Dana 44 27 and 30 spline shafts, as well as GM 28 and 30 spline (10 and 12-bolts). Couldn't break the 31 spline 8.8 shaft at a skosh over 6K lbs-ft... and they tried repeatedly!

 

[Jim Allen]

Colton- I forgot to add in my earlier post, I think the reason the syn 75W140 oil is spec'ed in cars is that you can have the benefits of a heavier oil without the rolling resistance. That's versus a dino 85W90. My opinion, of course, but I don't logically see the average car ever really "needing" a 140 grade gear oil of any type.

 

[Y_K]

Originally Posted By: Colt45ws
Do you know how much impact gear ratios have on temp?
My car has a 2.73 gear set while the CVPIs run 3.27 or 3.55. The Mustang is probably a 3.27 or 3.55 as well. Could this be the reason?
My P71 has a 2.73 on the tag.. But I think it is the expected use that makes the difference. Downtown patrol cars crawl around the city blocks for extended periods, and this slow motion heats up the diffs more than a chase. They also do breaks every 5-6k.

 

[Jim Allen]

Actually, slower = cooler, faster = hotter.

 

[Zaedock]

I remember reading somwhere that Ford started to spec 75W140 for noise issues. IIRC, there was a TSB on gear whine, and the fix was the thicker (and synthetic) goo. I'd have to try and find that.
Whatever it actually is, I've always run 80W90 in my off road rigs and never had a problem. Well, never had a problem caused by the gear oil. That's with 5.38's in one of my rigs.

The Ford 8.8 and Visteon axles are pretty good units. The only few issues I am aware of, is the axle tubes spining in the centersection during hard use and the main caps on the 8.8. There are aftermarket covers with built in cap girdles.
Some also balk at the c-clip shaft retention, but with rear disk brakes, it isn't a big deal, IMO.

 

[Zaedock]

Originally Posted By: Y_K
Originally Posted By: Colt45ws
Do you know how much impact gear ratios have on temp?
My car has a 2.73 gear set while the CVPIs run 3.27 or 3.55. The Mustang is probably a 3.27 or 3.55 as well. Could this be the reason?
My P71 has a 2.73 on the tag.. But I think it is the expected use that makes the difference. Downtown patrol cars crawl around the city blocks for extended periods, and this slow motion heats up the diffs more than a chase. They also do breaks every 5-6k.


I have to disagree with that. If you had a temp gauge on the diff and compared the city to highway use, the highway use temperature would be higher (probably much higher). More revolutions = more heat. Likewise, while there really isn't much difference (at least in the off road world) between a 2.73, 3.27, or 3.55, the 2.73 would run ever so slightly cooler.

 

[j_mac]

Thanks for the info on the axle assemblies guys.

The concern I had is that maybe some of the components in the rears are made in Mexico and then assembled in the US, but I really don't know.
I remember how the old 5.0L cars had Borg Warner T-5 transmissions. The T-5 was a very durable transmisson that would last forever as long as it was driven by someone that could drive a standard shift well. Ford used the T-5 in the V-8 cars until 1996. About that time Tremec bought out Borg-Warner and shifted production to Mexico. For 1996 and newer they put the T-45 transmission in the V-8 mustangs and if I'm not mistaken they were made in Mexico. Ford immediately started having all sorts of problems with this new transmission.
It was at this same time that all of the rear ends started making noises and going bad. I assumed there was a link. Also shortly after the 1996 changes, a buddy of mine bought a Ford Motorsport heavy duty T-5 transmission for his 5.0L street-strip car. It had a big sticker glued to the top of it that said "Hecho en Mexico" He took the original Borg-Warner T-5 out of his car that had hundreds, possibly thousands of powershifts on, a great deal of which was on the dragstrip with slicks. The car was supercharged and was probably putting out about 500hp at the time. He figured it was a matter of time before the stock transmission broke, so he took it out and used it in another 5L he had that needed a transmission. Mind you that this transmission worked perfectly still.
Anyway, he put in the Ford Motorsport "heavy duty" T-5 that supposedly had a significantly higher torque rating. The one with the "Made in Mexico" sticker. He took the car to the dragstrip, put on his slicks and on the FIRST LAUNCH the transmission exploded!
Does anyone know what diveline parts are Mexican on the 1996 and newer cars. Or did Ford simply cheapen them some other way?
I've been wondering this since 1996!
I know from personal experience that the 1995 and older 8.8 axle assemblies were rock solid reliable, durable and [censored] near indestructible. And they NEVER made ANY noises!

 

[Y_K]

Originally Posted By: Zaedock
More revolutions = more heat.
Could not agree more, except for the extremely low speeds. That's what cabbies learned hard way.

 

[Jim Allen]

Originally Posted By: Y_K
Originally Posted By: Zaedock
More revolutions = more heat.
Could not agree more, except for the extremely low speeds. That's what cabbies learned hard way.


I'm afraid I'd need to see more than anecdotal info to have my mind changed. I've spent a good 13 years observing axle oil temps in a great many circumstances and slow speed work just doesn't result in all that much heat. A lot of stop & go, especially in a "lead-foot cab driver" way (as opposed to a silky "limo" style), can work the oil up to something close to a high speed situation but it's not a critical temp level. There are other things at play besides heat that can work over gear oil. I'm not saying cab work isn't hard on an axle, just that I strongly doubt the issues are primarily heat related

Anyway, if you can point me to more info on the topic, YK, or anyone else, I wouldn't mind furthering my education.

 

[Zaedock]

Originally Posted By: Y_K
Originally Posted By: Zaedock
More revolutions = more heat.
Could not agree more, except for the extremely low speeds. That's what cabbies learned hard way.


There's no regular cabby on earth that beats a rear end up like my Jeep. At ultra slow speeds, in compound low range, rolling on 150 lbs/ea 38" tires, the differentials get warm to the touch. That's after driving all day.
If I take my Jeep on the highway, the diffs get hot. With the tires/cage/recovery gear/tools/armor, my Jeep weighs in about 4500 lbs, which is probably equal or even a little more than a full size Crown Vic/Caprice (if there are any left). Most cabs are also automatics, which is easier on driveline components than manuals.

This is my thinking/experience: Heat is caused by friction. The carrier bearings, pinion bearings, and outer wheel bearings (on a semi float axle) are simply not moving as fast during slow operation. I just don't see how/why a slow moving axle would produce more heat than highway use. In addition, having been in many cabs in NYC, they pull out and sit in traffic.

If you have any sources/papers supporting your thoughts, that would be a very interesting read.