anybody ever experience a slight shudder or a feeling like your driving over a slight rumble strip when you pull away from a stop sign or traffic light, especially when I'm starting into a turn after I've stopped. my 02' FX4 only has 2500 miles on it.....is it my rear, tranny????? Thanks in advance.

 

Damn... I need to get my mind out of the gutter. I was misleaded by the topic.

 

Yeah, I guess I'd hear about that one on the safe sex message board, huh? HA HA

 

Checkout the Transmission forum. There's so info that might apply to your problem...

 

In order for U-Joints to live long lives, they must have a certain amount of angle to them. Unfortunately, the weight of the driveshaft and the geometry of the joing phasing (draw it on paper and you'll see that the shaft ends pivot off-axis) causes the pivot to be felt by some drivers -- and you're one.

Two things happen -- 1) the shaft starts rotating at a speed where it's wobble is less pronounced than the overall spinning inertia of the entire tube, and 2) the rest of the vehicle masks the vibration from 1 -- and you simply don't notice the wobble any longer.

On vehicles that have too much angle (like when lift-kits raise the transmission with no regard to tipping rearward the tranny and tipping upward the differential housing) the wobble is overshadowed by the change in position of the drive tube due to the sever angle of the u-joint.

Another cause for the wobble that you feel is on vehicles that have been properly designed for the angle that is produced by a moderately-loaded vehicle -- but where the angle is too great due to the vehicle not actually being loaded (springs compressed) to that 'median' level of loading. This latter case can be easily diagnosed by convincing 4 or 5 of your heaviest buddies to sit in the bed while you try to duplicate the shudder that you are now feeling.

If your shudder stops 5 feet after you move, then you are probably simply super-sensitive to it -- to no detriment. However, when the shake is significant, pinion bearings and transmission rear bushings suffer short life.

The only way to truly tell whether your shudder is excessive is to verify that

a) your drive shaft is in balance (requires removal and machine checking

b) true measurement of the driveline angles and comparing it against design limits (good luck getting a copy of them).

Rotza Ruck

 

i have that same feeling some time's. i know mine is a weak limited slip rear end. that is doing it. only in turn's. i use mine off road alot. and i know the limited slip is not as tight as my 93 f150. my 93 never kicked out on me when i was off road in a tight spot. but this one has kicked out a few time's. but in the same breath. it should be the tighter it is the more the shudder should be there in a turn. i have seen older tsb's about added a second friction modifier. limited slip only. i have not tried this yet. but it's also still covered by ford. i have 5'500 mile's. so i'm not to worried yet. but. i'm also to busy to deal with it now also. hehe. good luck.

 

hmm... quit using ribbed

 

Trying to avoid any pullout comments...

You may need to add some limited slip additive (to the axle). If you don't have enough the clutches will grind when they have to slip.

Ian

 

thanks for the suggestions gents.....stay safe

 

Add OEM Ford friction modifier or Dana part# 43161. I used a generic modifier in my 1979 which has an Auburn that I installed. I had problems "like you are describing", until I added a small bottle of Dana friction modifier.

 

GET IT FROM FORD IT'S NOT THAT MUCH, MINE DID THE SAME THING. 1998 WITH 3:55, THE CLUTCHES ARE CHATTERING.

 

Ditto. Sounds like the clutches chattering whwen the truck is turning. The friction modifier takes care of that in most instances.

-Joe-