Maybe someone that's a true Ranger ( 92 Super Ranger-4.0 automatic tranny ) can give me a better clue before I pull all my hair out. I get this vibrating pounding for lack of a better wording when I get to about 41 t0 50 mphwhen I apply a little throttle. It shakes the truck. At first I thought it was a misfire so I installed new Autolite double platinum plugs and a set of premium plug wires. (didn't help) I installed new semi metallic brake pads and new bands on the rear. Then new rotors and wheel bearings. ( still had the problem ) Pulled the drive line and found two bad U-joints but replaced all three and had it re-balanced. That took care of the drive line problem. I could tell the shocks were worn so I replaced all four with Monroe-Matic's. Had all four tires rotated and rebalanced ( comes free where I buy tires ) Went back and repacked, retightened front wheel bearings and rekeyed. Bought a special MAF spray can of cleaner and cleaned the MAF sensor being very careful of handling and reinstalling same. Checked the king pins by movement from the o degrees to the 180 degree position and noticed no play. Under 35 MPH it's o.k. it seems . The only thing I found so far is a little oil on the center spark plug but the compression is 175 or better so it must have a little valve stem seal leaking. Have run a couple cans of injector cleaner through the tank but the problem is somewhat still there. Not as bad as when I first started this journey though ! I did get caught on an out of town trip with a leaking (anti-freeze coolant) intake manifold gasket and had to have that repaired by a auto repair shop. (Fel-Pro gasket set ) Has anyone got any ideas on this or had the same problem before? Seems to happen mostly when you press on the throttle after 40 MPH. oh yes, tranny was rebuilt two years ago. This is now my STRESS RANGER and any advice would be appreciated. I hardly know what kind of shop to take it to right now and I've been working on auto's 60 years. Thanks Capt Hank

 

so you are sying the vibration comes when you give it gas over 40.......So if you were just cousting at 45 then there is no vibration?............Does your truck have the slipyoke in the driveshaft.......you said you had 3 ujoints maybe you don't have the slipyoke?...........any chance it is a fuel delivery problem?

 

Yes, that's whenyou feel the vibration mostly~~~~after about 40. It seems there is a very unpronounced little vib even after 40. Yep, slipyoke in the driveline as this is a two piece driveline but that was taken apart by the driveline specialists who rebalanced it and cleaned and lubed. I By the way, by cleaning and relubing and rebanding the cover, it got rid of that little clunk in starting off as that is what they will do if your slipjoint has gotten dirty and needs lubing ) Thanks for the reply capthank

 

Capt Hank - can what you describe be akin to the kind of rumbling one would experience when stepping on the gas in a vehicle with a manual tranny where one should have down shifted instead?

 

Does any of this happen during shifts? Or is at lower or higher rpms?

 

I don't think it has anything to do with the shifts as I had that tranny rebuilt two years ago and it shifts fine. One thing I think I have noticed though is when you start up and the engine temp guage is still cold (less than a 1/4" off the cold side of the guage) and it doesn't seem to get this vibration then~~~~of course when you start driving then everything warms up including all the suspension and drive train? The auto tranny will be in overdrive and that puts the rpm around 2500 I would say by memory from where I sit right now. As far as a fuel supply problem, I don't know but wouldn't say so as it goes like a stripped A** Ape on up to sixty or seventy. That's the whole mystery of this beast ? It's like a pounding vibration like when you used to get one of those big knots in your tire when the tread seperated on the inside? My tires are real good though and just rebalanced two weeks ago. capthank

 

Capthank, have you inspected your motor mounts? Not a huge problem with them being bad but if they are. Under strees the engine can move around alot. Particularly under the load of acceleration. Also how is the tranny mount? Just throwing out ideas that are easy to check.

 

Haven't checked these yet but have thought about it. Especially motor mounts as I think the transmission place would have said something about the tranny mounts when I overhauled it two years ago as they did mention the center drive line support was getting weak then and I changed it. Thanks for the comeback, capt hank

 

Just got back under it yesterday again and checked those engine motormounts and the tranny mount and they are all good. I did notice the right front tire even though it's still got really good tread and I had them checked and rebalanced again but they have a large 3" balance weight on one side of that rim and exactly the same plus about a 1" weight on the other side of the rim making about 4" of weights. This seems excessive lead to me to balance a tire?

 

Unless you are running 31" tires or bigger that is a very large amount of weight to balance a tire I would take it back to who rebalanced them and have them break the beads of the tire and spin it 180 degrees on the wheel. The tire should balance alot better and also pay attention to the wheel to see if it is bent. If so that would defintely cause a bad vibration at certain speeds. The person who did your tire work may not like his job or sure doesn't take pride in his work. These issuse should have been addressed the first time he did the work. Anyone who has done tire work knows this. But this comes and shop managers are worried about quanity not quality.Its a place to start.

 

I agree, that much weight to balance a tire is a bit excessive for a standard size tire. Sounds like a bad tire, seperating or out of round. I certainly wouldn't want to run a tire like that, much less on the front.
If you have the same size tires all around, swap the front and rear on that side, and see if the vibration is reduced or changes in any way. Or, it the spare is good, swap it in place of the suspect tire. If the vibration disappears, you have a solid answer.

 

Thanks for the comebacks from you guys but I have already this this swapping of tires and going to the spare and swapping out for the two tires that I thought might be causing it but still that vibration . Took it back to America's Tires where I havbe been buying tires but to another location this time and they told me that it wasn't the tires out of balance but they thought it was the tranny that was causing the problem. I said that I had it rebuilt two years ago but I checked my receipts this morning and it's been almost four years. (Time really flies when you have a Ranger ! ) I called a good tranny shop this afternoon and they were busy until tomorrow morn, when I'm taking it in. I described the problem on the phone and he said " Are you sure you don't have a mis- fire? So any ideas on that even though I have changed to Autolite Double Plat. and new supreme 18MM plug wires an pulled the coil, examined for cracks and cleaned it. Thanks capthank

 

O.K. everyone, listen up~~~~~another new development. Just got back from the tranny shop and they are saying it's in the engine! A miss so this is the second tranny shop to tell me this so guess we have to go ENGINE. Have replaced the plugs with Autolite double platinum and a new premium set of ignition 8MM wires but it still has this miss so any new suggestions people ? Would love to get this thing back to par again. Thanks Capt Hank

 

Capt Hank - I was doing some reading in the Haynes manual. Perhaps someone here with more experience can comment on this. Could your ignition system be fouling (i.e. the Powertrain Control Module)?

I'm not a fan of aftermarket sparkplugs (splitfires and the like) and thought maybe the plug configuration and/or wires are messing with the ignition system and the computer. But my experience is limited to an MSD system I installed on my 90 Escort GT (ran a hotter coil, 9 mm wires, and aftermarket sparks) and found that all I ended up doing was cooking wire sets, plugs, and more gas. When the plugs/wires would begin to fail, the vehicle would stutter under acceleration like I had water in the line. It didn't rumble like your situation sounds, but it surge/stutter when I stepped on the gas without downshifting.

 

Well to get back to this perticular problem I took it back to that tire place and made them rebalance that multi weight wheel that took somethingh like 6 oz. to balance and they split the bead and rotated the tire 180 degrees and re balance it and this time it only took 2 1/2 ozs. to do it so that was agood suggestion but as it turns out it was not any thing to do with supennsion problems or balance. the center cylinder on the left side (5) was not firing so I had a bad mis fire. Had been running injector cleaner before that and it still didn't help it so I was finally able to get in there with a long screw driver and get the injectot electyrical cap off there and turning the ignition on, I had 12 volts. So be it. Guess the injector just failed mechanically ? Unless somebody else has a nother suggestion ? Looks like you are going to need to pull the intake manifold asnd depreeurize the fuel rail and replace that injector and get a gasket and re assemble everything!! capthank