Jerk/Jolt
 

I noticed this about a month ago when on a 9 hour road trip.....and it happened a few times yesterday when coming home at night, maybe 15 mile drive.

When travelling at steady speed (foot on accelerator, but just to maintain speed, not really accelerating), I will notice a jerk in the truck, and at the same time a dull "thumb" is heard.

Happens in the area of 50mph +/- 10mph. Using cruise control or not doesn't matter. I have an auto, and here is what I can do to describe the issue.

It feels like if I were driving a manual, and let the clutch out and put it right back in without giving it any gas - kind of a front to back jolt.

The jolt is more of a decelerating as opposed to acelerating jolt (hope you understand what I am saying).

It happened speradically, but from what I can see, the RPM's don't change. Everything is fine after, I will just get the jolt every so often. Its enough for my passanger to yelp and ask what happened.

The days it has happened it has been rather windy and snowy, I don't know if that matters.

Last week I went on a 150 mile drive, didn't happen at all. and I was doing 50 the entire time but it happened yesterday.

Am I being paranoid, is this normal?

im not real sure what the problem is but do you have a CEL? have you cleand your MAF?

No CEL.

No I didn't clean the MAF - I will this weekend. I gotta pick up some stuff to clean it with and maybe change my air filter while I am in there.

Any other ideas?

whens the last time you changed the tranny fluid and rear diffentrial fluids

Never have (don't yell at me).

I got the truck a few months back. Don't know the history other than what the previous owner did at the dealer which I got a printout of. Whats a service package 1 and 3?

Anyways, I was planning on doing the diff this sumemr myself, and the tranny this summer as well (a complete drop the pan and the works).

How do ou tell is the fluid is bad? I smell it and it smells like an engine. And a pinkish brownish orange in color.

I think its to be red in color

open your oil cap and see if there is a milky color on the bottom of the cap? also is there any noise coming from your engine area like a ticking or rattle kinda noise?

No noise from engine. Oil is OK. I just changed it 3k ago and this is the first time running synthetic in this engine.

I actually "learned" how to check my tranny fluid the right way the other day, and when at running temp, the level is right at the bottom of the x-thatched area on the dip stick. Its not under, but right at the bottom mark of the "OK" area.

I just called the carquest near my place, going to get some MAF cleaner after work for $5, but its gonna be -30 outside this evening, so I will have to wait until the weekend to try it.

well mine was sluggish sometimes until it was warm and then i cleaned my MAF and hadn't had problems since

you said it was windy and snowy both times when it happened? Perhaps you had a tire loose traction which would slow you down some and when it regained traction it would give you that small jolt.

Unless you get it happening consitantaly in any condition I don't think you have a problem.

I would recommend you get your tranny fluid changed though. It should be a bright red color. Also if it smells burnt at all it's used up.

add some more tranny fluid if its at the bottom of the line. it would be a temp fix, my bet its something with the tranny. change the fluid asap!

I guess I might as well change the tranny fluid now, whats the dif, this summer or now - might as well get it done.

I will clean my MAF sensor anyways. I went to the carquest down the street, asked for MAF sensor cleaner. They gave me a spray can of "Fuel Injection and Air-intake Cleanser". Is that the right stuff?

Also, should I get just the tranny fluid changed, or go with the whole sha-bang and drop my tranny pan, new filter and all?

Umm, uh-oh....

Making my apt RIGHT NOW for tranny fluid change

drop the pan, new filter and flush

My truck jerks/jolts, but as someone said earlier, it's the trukc losing traction temporarily while the LS kicks in. (So i'm guessing) Mine's a 5-speed, though.... It freaked me out at first, but it only ever happens on icy/snowy roads. Sooo...I'm writing it off as loss of traction.

Is this what happens when L/S kicks in? This is my first vehicle that has L/S.

no you will not notice when the LS "kicks" in or out... its limited slip so it slips in and slips out... you may notice it because it slides the rear end out when it slips in.

Yeah...the jolt is not an indication that LS has engaged...I just thought it was the LS kicking in and the truck re-gaining traction. I may be wrong...heh

Zach...If the clutch packs of the limited slip are worn it could give a sudden jerking feeling. I actually know exactly what your feeling it. My ranger would do it on occasion in the same situation. Foot on the pedal just to maintain speed around 50 or 55 mph. I came to the conclusion that it was the LS. Try adding some friction modifer to your diff or completely change the fluid but make sure to add the modifier. Unless you use the Lucas synthetic stuff. Read the bottle the modifier is already in it.

Just wanted to add another comment about the tranny fluid. How many miles are on your truck. Typically if this was not a service that was performed routinely (every 30k or so) changing it for the first time at high miles can have a harsh impact on the tranny. A lot of ppl start having problems after the first tranny flush at high miles.

I have 66k miles on my ODO. Don't know about history, like I said. diff drain is planned for near future as well. I will go synthetic, I heard you don't need the l/s additive with synthetic.

I'm just waiting for it to get a bit warmer. I would like a day above freezing to do some upgrades.

The Lucas synthetic worked well enough for me without adding a modifyer. I didn't have issues until a shop drained it when changing some seals. They swore they used a modifier. I doubt they did. I never got to changing it again before it sold (too busy with a new baby).

When you buy your gear lube just read the bottle, It will tell you if it's ok for l/s or not.

I used Mobil 1 synthetic. It's safe for l/s.

not sure if you can use it or not i would get some electrical parts cleaner spray they also have stuff called MAF cleaner

Definitely change the tranny fluid, but that doesn't sound like exactly the problem. As my screen name states, I am on my fifth ranger. My last two had a thump present when driving at lower speeds. I also had a slight loss in power when I tried accelerating it just didn't want to go. The first time I noticed it was in my 02' Ranger 3.0 liter V6. Then, I noticed it again in my 04' 4*4. My current Ranger is an 08' 3.0 V6. I haven't noticed anything. From other posts, I gathered that it was possibly a fuel pressure problem. I noticed by keeping the tank over half full and using quality 87 octane -- not the cheapo places, but name brand (I prefer Shell) it nearly eliminated the problem. Also, others were complaining about the 02's in particular that a recall existed on the drive shaft needing to be relubed. I'm not sure what other years were involved. But, definitely change the tranny fluid. It may look fine, but be at the end of its life. Especially if it smells burnt. Make sure they put in the proper kind. Mercon is the standard, but there is different types for different vehicles. I think my 02 and 04 took Mercon 4, but my 08' takes the new Mercon 5. Hope this helps.