Technical Jack under differential

A friend was telling me his owners manual says not to jack his Ford (8.8 I think) up by the differential, tweaks the rear end alignment. Evidently I have been doing it wrong for 40 years.

 

Ask him to show you the manual.

 

I don't think the 8.8 has been available for 40 years.


(yes, it's in the manual....)

 

It's true, I've seen it in the owner's manual as well.

 

It depends on the rear axle and the weight of the vehicle. Those rear ends that have a drop-out differential are less susceptible to being tweaked, whereas those with a cast center section and pressed/welded in steel axle tubes do experience quite a bit of strain where the axle tubes enter the center section. I try not to put a jack under the center, but rather under the axle tube near the backing plate, or under the leaf spring perch, depending on suspension type.

 

I always put a block of wood between jack and diff.
Do you think this will make a difference?
Guess I've been doing it wrong for years too.

 

Old chevy shop manuals (late 60s) show it's ok to jack from the center of the rear housing

 

another thing is the 8.8 from a explorer/ranger is offset to one side which it will cause a unsafe lean if jacked by the pig and the weight on the rear is near its maximum in that vehicle ( explorer ) .

 

That makes more sense. I use both center housing and under spring pads for one sided jacking.

 

I doubt any of our cars weigh as much as an SUV, maybe a 60's luxo-barge. Makes sense though.

 

This is interesting. I'm like every body else, I've all ways jacked up the pumpkin and set the stands up. I always leave the jack under the pumpkin for safety.

 

I wouldn't want an axle under my car I had to worry about hurting just by jacking it up...

 

Pffffft. I've been doing mechanic work for 50 years...professionally for 45 and I can't count the number of times I've jacked up cars under the differential to put them on stands...never had an issue. Must be a ford thing.
Although, if the exploder axles are really offset to one side, I wouldnt' jack under that pumpkin simply because, as Stimpy said, it would make the car tilt to one side and could fall off the jack.

 

Yes, that should work. And pump faster.

 

and I also forgot the 8.8 does have the thinest tubes of all the vehicles I have seen .188 vs .250 of most others , seen some O/T turbo'd moostangs twist the tubes up and some jeepers bend them . and they place the springs close to the axle ends so the weight isn't put on the center of the assembly so the tube acts stiffer . but most of the cars built here either the tires will break loose or the body is real light as mentioned . I was going to consider the 8.8 for my 50 untill I realized the 8.5 10bolt is just as strong if not stronger

 

The 8.8 out of the explorer or ranger is really not something to put in any kind of performance machine they don,t even hold up in a ranger.

 

most rangers used a 7.5 if it wasn't a v-6 and then it was a option for the v-6,

a 8.8 is the standard axle for the moostang and they hold up to some high torque and Horsepower and the moostang guys actually steal parts from the explorer version as the axles have more splines and hold up better .

 

In the back pages / fine print of the manual - it says......"weld the tubes to the housing, if you're not a panzy."

 

I can't understand what you're trying to say........ maybe a little punctuation would help.

 

The 8.8 Ford rear is more than adequate for most street rods or hot rods. I have built three cars with them but I did weld the axle tubes to the housing and after welding the tubes and spring perches I took the rear to the local off road chassis shop and had them straightened. The welding will warp the tubes even if you are careful. They are cheap and plentiful at the local pull a part yards.

 

Actually if it is a shop manual like a dealer shop manual it is most likely a liability thing. Some cars have an offset rear axle, think Ford van for an extreme. Jacking on the punkin can lave it a little off kilter and if it falls it can squash you or break the car.

Late model cars have predetermined jacking points and they like professional mechanics as well as car owners to use them.

 

I'd be more concerned with a Ford rear end in my car!!

 

Shouldn't jack under a diff, eh? Looks like I've been doing it wrong for the last 50+ years...............

 

I put them in 4x4 rigs for customers, where they see a gear-multiplied 15,000lb.-ft. of intermittent torque. They survive nicely, with just the tubes welded to the pumpkin, running lockers, and 40" tires.

Have you got some failure pictures?

 

Interesting. At one time I was seeing a lot of outer bearing failures... almost always on the right side, and 90% of those were police and CHP Crown Vicks. Now I wonder if they were bending the tubes picking them up for tires and such.

 

It's in the Mustang manual, so it's not just the heavy SUVs or offset diffs.

 

For some reason, I'm going to leave the Chevy is better than Ford thing alone this time.

 

I understood exactly what he meant. Nothing wrong, punctuation-wise, with his sentence. To add commas would be superfluous.

 

All brands have their strong points and their weak points.

 

Sorry to say, I've reread it several times, and still don't have a clue. Maybe it is just me. Doesn't really matter.
I guess sometimes we speak in slighty different ways.