Shudder when accelerating uphill on curve

[Kleetus]

FYI... Ford's factory fill already has the LS additive, you can add more if you don't want it to grab. All I can say is good luck and God bless if you put more in...

Bottom line if it just started doing it out of the blue, I'd find it really hard to believe the clutches are the problem. They get looser with age and wear, not tighter... Something else is going on, maybe a bearing in the carrier, or the mid ship carrier bearing on the drive shaft... the rubber boot that it rides in could be starting to go, I've seen some weird things happen when they start to wear, it's more apparent in larger trucks, 26000 lb and up, but they all do it sooner or later. Little toyota's are really bad for it. shakes the whole truck something fierce.

 

[Zookie400]

It started doing it recently, and the only other event that lines up with when it started was when the dealership I had problems with replaced the fluid in the rear end. Hmm.....

as of a year ago when i quit working for ford, there was no gear lube that had the friction modifier in it, it was a seperate little bottle that needed to be added. i know the same goes for GM, mopar, mitsubishi, and mercedes. i know for fact that on the escapes there was a service bulletin that required us to put in a full bottle of the stuff and go do several tight circles to work it into the clutches because the factory had missed a batch of them.

at worst, you add the little bottle, it doesnt work, and you are out $10 versus 700.

 

[Mark Hastings]

I'm starting to get the same on a few of my Units but one seems like the noise is coming from the trans the other is the rear end on up grades no matter what the speed and the friction modifier is the key because Ford misses alot of the trucks that roll out.Two out of Five trucks are making the noise in my Fleet, it starts off as a popping every now and then and gets worse.

 

[Kleetus]

I stand, well, sit corrected on the inclusion of modifier on the stock fluid. I take that back. I was thinking back to a previous project, and remembered that little 2 or 3 oz bottle...

But I still wouldn't add any to it as it's just going to further shorten, and decrease the limited effectiveness of the LS rear.

 

[Mark Hastings]

All my trucks are 2006 with less than 60,000 miles.

 

[Kleetus]

supposedly City of Pittsburgh is getting away from the F and E series chassis because of transmission troubles, like they can't keep them in the trucks. I guess the don't appreciate be run hard from a cold start. Saxonburg Ambulance put two transmissions in already in their E series trucks. No engine problems, but the go boxes are seeing some problems. Mark, you might be on to something...

 

[TexasExcursion]

Update: I added some more to the rear end and thus far its done nothing. Put it in about 200 miles ago. I only get the shudder when I'm accelerating, whether up a hill or around a tight corner--but it's much more noticeable going up a hill.

One other thing: when the mechanics were looking at it up on the lift, they were able to hold one tire and the other tire would rotate about 3-4 inches--they said this was a sign the clutches were going out. True?

Any ideas? We're taking a trip in June from NY to Minnesota, so if I need to get this fixed between now and then, somebody let me know. The service manager at the dealership said that if the problem gets worse, it'll be just like driving a regular slip rear end. Basically it won't leave me stranded anywhere.

I'm out of my league here!

 

[Kleetus]

I don't know about the clutches on that score... there might be some significant wear on the spider gears though. Even at that, I still think they're FOS...

Full of "something"

The uphill flat downhill thing makes no sense to me. The rear end could care less the angle it's at. I'm thinking that something in the driveline has some wear on it, like the midship carrier bearing. it's only held in with some rubber anyway, and with the mileage you have, it's not out of the question it's starting to get a little loose. You ever crawl underneath and give it a shake to see how far you can move it?

 

[Mark Hastings]

If there isn't any play like a banging when you put it in drive or reverse then your rear end should be fine. It's like the dealer said that it would be like the old style slip Diff's.THey used to have the diff lock as an option in the early 70's because there was an option for it on my 71 F100 with a 9" rear end the only thing that was different was the chunk to hold the clutches so from my stand point with my fleet of 6.0's I wouldn't worry about it unless you want to spend the money to have it fixed.

 

[TexasExcursion]

I don't know about the clutches on that score... there might be some significant wear on the spider gears though. Even at that, I still think they're FOS...

Full of "something"

The uphill flat downhill thing makes no sense to me. The rear end could care less the angle it's at. I'm thinking that something in the driveline has some wear on it, like the midship carrier bearing. it's only held in with some rubber anyway, and with the mileage you have, it's not out of the question it's starting to get a little loose. You ever crawl underneath and give it a shake to see how far you can move it?

The only thing I see with the angle--uphill, downhill, flat--is the stress on the rear end. I'd think that if I'm towing a load up a hill, that's putting more stress on the whole driveline versus going down a hill or driving on flat ground while coasting.