Hi everyone.

First post, here.

I've got an old 1984 ranger(6 cylinder, manual trans). I use the truck as a backup to my work van, and the truck has came through in the clutch(no puntended) many times throughout the years. The truck looks like hell, but I can't help but to love it. I've had the truck since about 1980. It at one time sat in my garage for almost 3 years....not good, I know. I got into a jam, pulled the truck out and stuck a battery in it, changed the oil...and away I went Anyway, that's kind of the back story.

The problem I am having: When I would get out on the highway for a long stretch and then get caught by a stop light while going through some small town along the way.....upon the light turning green, shifting into 1st and hitting the gas, there would be sort of a thump coming from the rear. As time went on the thump would be accompanied by a jolt. As time went further it would almost seem to lift the rear just a bit when the thump/jolt occured, and almost a momentary grinding sound.

edit: I just remembered and should mention....one night I backed the truck into the driveway and the next day I wanted to get into the garage. Without turning the vehicle on I shifted into 1st to just roll the truck away from blocking the door. It wouldn't roll. So I gave it a bit more of a shove and it sounded like whatever was stuck broke loose(unstuck) so I could then roll the truck.

During my last inspection I mentioned it (after) the inspection. The guy said it was probably the springs...he said it was somewhat common in older vehicles with a lot of miles. I'm thinking maybe it's something else.

I'm somewhat of a novice when it comes to diagnostics and working on vehicles, although i've been known the go elbow deep in it if the need arose.

I won't speculate(too much) and will wait for you more knowledgable folks to chime in....but it seems there is something going on with the axle or transfer case.....?

I appreciate any feedback anyone can offer. I am thinking about purchasing a 1980 F100, but that's a whole other can of beans....but figured I might as well join the website now.

Thanks

 

First thought that comes to my mind is: U-joint. I'd crawl under the truck and see how the U-joints look - try turning the driveline by hand and see if there's any play.

What's the service history on that truck in regards to the rear differential? When was the last time the fluid level was checked? Same question for transfer case (if it's 4WD, if not then, nevermind) and transmission...

 

^+1 on the universal joints if you have a one piece drive shaft.

If you have the two piece drive shaft, take it apart, clean & regrease the splines, Ford has a TSB out on a PTFE loaded grease just for this application. Super Lube markets a PTFE loaded synthetic grease that many parts stores & some WalMart, KMart, Hardware, Home Center stores carry that'll likely work & cost less, or if you have it in stock, use a Marine wheel bearing lube thats formulated to operate in a high moisture enviorment.

More thoughts for consideration, let us know what you find.

 

Thank you guys very much for responding.

It's a long story that i'll try to cut as short as possible....

The truck sat for quite a while in my garage, so long the wife gave me a choice...get it out of the garage or get rid of it. Around that same time I had purchased a Dodge Shadow that was in really good shape from a friend who really needed some cash. So, about 6 years ago I bartered the dodge and some cash to have the engine in the Ranger rebuilt. Long story short, the guy was the new owner of a previously reputable garage(he has since gone out of business)...it was a nightmare. I suspect he threw a used engine in the Ranger. But he also said he serviced the trans, fluids, etc. It was such a nightmare and runaround that I eventually just said to hell with the guy. Anyway, he said he serviced the trans, fluids etc. I had big ideas for the truck after getting a rebuild, but kind of scrapped those ideas after I had no confidence that the engine would last. I've probably got lesss than 20K miles on the truck since then...like I said, it's kind of a back-up vehicle.

Knowing what I know, I should have checked behind him, that's my fault. Thanks for the advice.

Thanks. I'll check the u-joint for play. Taking apart the axle might be a bit more involved than I can make time for right now, but i'll put it on my list.

There's another symptom I failed to mention: It might be my imagination, or the fact that I had quite a load in the bed at the time....but, I was going around the interstate off-ramp curve and it almost seemed like the rearend dropped a bit on one side and caused the truck to veer to the other side. Later after stopping at a light I heard the same sound I mentioned before and things seemed okay again This might be a really stupid question, but is it possible the axle is broken(or some such problem), or would that be way too obvious and the truck would not be operable with a broken axle?

At the risk of making a long story long: Some comic relief.

When I picked the truck up after the engine was "rebuilt", when I started it the starter was grinding something fierce, and it was loud. I stepped back in and asked the guy what that was all about. "Oh, your flywheel is warped really bad!" He pulls the flywheel and I get a machine shop to check it to see if it was warped(it wasn't), and they press on a new gear/ring.

I go to pick up the truck again, same problem, less grinding, but the starter is sounding unusually loud. I look up under the truck, and there it is, in plain sight, the flywheel.

I go back in and tell him, man, that starter sounds really loud, and there's still some grinding(which of course will destroy the starter and/or the flywheel).

He says, "Yeah man, I did everything I could, that flywheel is just warped to s***."

Me, "Hm, did you try putting the separater plate back on?"

Him, "They didn't put the plate back on?"

Plate goes back on and problem solved.

Anyway, thanks for the replies, and sorry for the long post.

 

I wasn't suggesting taking the rear end apart, or pulling an axle, just drop & take apart the two piece drive shaft, to lube its connecting splines, Only if you have a TWO piece type driveshaft. If the splines rust up they can't easily move fore & aft when the engine applys torque & the differential tries to roll up as torque is applied. When the splnes bind up & pop loose, they can do so with a boom & lurch, sorta what your describing & since it sat for two
years without moving, that would allow them to rust in place & make it hard to move.
EDIT:Here is a thread on the two piece drive shaft slip yoke binding problem. https://www.ford-trucks.com/forums/1...-anything.html
EDIT: BTW Welcome to FTE!!!!

 

Thanks pawpaw!

Sorry I haven't gotten back yet, the weather has been kind of messy the last few days to get up under the truck to take a look.

Driveshaft: I checked to see if there was any play, there was (absolutely) none that I could detect. Also, it is a one piece shaft. I was hoping there was some play in the u-joints as it makes a lot of sense that it would be the problem. Maybe i'll drop the drive shaft, inspect, clean, and lube, just to eliminate that as a problem. Do you think that is necessary?

Also took a look around while I was under there to see if I could see anything obvious....springs, shocks, mounts, etc....all appear to be intact and tight.

I see now that you didn't mention axle(s). I guess that was my own head reading into your post. Sorry about that. I suppose it is bouncing around in my noggin that something is going on with the differential or axle.

What should I check next?

It does seem that my problem for the most part only happens after I have had the truck out on an open stretch for a distance, like on the interstate. It doesn't really occur at any frequency when I am just driving a short distance(s) around town.

 

Do you hear any kind of noise when this happens - either a low growling noise or a high-pitched whine?

 

I think I do hear a slight grinding noise(if there a grinding it's not real audible/loud)....sometimes...mostly when i've had it wide open at 55-65 for quite a distance.

Also, sorry, earlier when I said transfer case I meant differential. It's a 2 wheel drive truck.

 

Well since its an 84 & nearly 30 years old, it sure wouldn't be a bad idea to relube the universal joints.

Seeing as how you had the lurching incident with a load on, check the rear springs, shackels, hangars, shocks, as something might have popped, like a leaf spring, or shackel weld, or shock mount, ect.

On it seeming to lock up & not want to roll & with the expierence you had with the guy reworking the engine, ect, I'd check the running gear lube level. maybe change it out. I'd also check the rear wheels, to make sure the brakes aren't dragging & flush the brake system with new Motorcraft DOT-3 fluid.

More thoughts for consideration, let us know what you find.

 

I'm sorry, i'm new to some of this. When you say running gear lube level, are you talking about the differential fluid? If so, what is the best way to check the fluid? Also, would it be just as a good an idea just pull the cover and drain, new gasket, and new fluid...that way I can take a look inside? Or would that possibly open the door for potential problems...seeing how the truck is 30 years old?

I checked under the truck for other potentials(shocks, springs, etc) everything seemd okay, although I should probably make extra sure using a light.

About 6 weeks ago I did the entire front brakes myself...pads, calipers, rotors, bearings, flex hoses....and flushed front and back...even did my best to clean inside the master cylinder without letting it go dry.

However, i'm glad you mentioned brakes. I'm pretty sure the first time I heard the sound was right after I had the rear brakes done back I think 2 years ago. I then hit the road for a 150 mile trip to my brother's house. I initially thought it was the brakes slapping back into place or something of that nature. But i've since had inspections done at the same place where the rear brakes were done and haven't had any problems reported. Maybe they're not checking the same side as the problem....maybe as you suggested, I should.

Like I said, I don't drive the vehicle that much, but have been more and more over the last few months.

I apologize that i'm throwing so much out there, i'm sure it probably doesn't help you help me figure out the problem. Right now I need to take the time to follow the advice given and report back with what if anything I find.

I really do very much appreciate the patience and advice.

 

Yup check the transmission, transfer case(if yours is a 4WD vehicle) & differential. Seeing as how the gararge tech you had do the engine work was so neglectful about the things you posted about, I'd sure check behind him on drive line fluid levels & make sure whats in there is the correct fluid level & type. If all those fluids have been in there for close to 30 years, its long since time for them to have been changed.

If the shocks are OEM, they're likely long past due for a change & with the load shift you spoke of I'd sure have a Close look at All the rear suspension components, like welds, bolts, hangars, spring leafs, ect.

If you suspect the rear brakes after the work that has been done, raise the rear wheels off the ground & make sure the emergency brake is fully releasing & that the rear brake shoes aren't dragging. If they are & you have some air in the rear wheel brake cyl, it can get hot from the shoe drag, expand & cause more wheel drag, that'll make it difficult to move after coming to a stop.

So take the time to have a close look at the drive line & brake components.

 

Weather and schedule permitting i'll try to get on those things Sunday.

When I pull the differential cover is there advice on what I should look for when doing a visual inspection? Since I have the cover off is there any things I should might as well replace while I have the opportunity? Expense given ample consideration, I do like the idea of replacing (somewhat) easily and wisely replaceable items when the opportunity presents itself.

 

You don't have to pull the differential cover to change the differential lube.
Remove the differential fill plug, insert a piece of tubing long enough to reach the bottom & attach the tubing to a marine lower unit hand pump syphon tube & pump the differential fluid out.