I've been noticing that when I shift from first to second after I take off from a stop(even before I've let the clutch pedal up) I get a soft "thunk" sound and feeling from under the truck, kind of towards the middle to rear. I also hear and feel the same thing when shifting from second to third but it's a lot more subtle. And then I feel or hear nothing on the 3-4 and 4-5 shifts. It does this whether the transmission is warm or cold.

I put the truck in neutral, set the PB and got under it and turned the drive-shaft by hand and the u-joints don't move but the DS does turn quite a bit at the rear axle before it stops. The u-joints are pretty oily though. It's a single drive-shaft with no carrier bearing.

I'm going to replace the transmission mount with an Energy Suspension's poly mount (stock one has 130k miles on it) and I've got the Mercon-V to change out the trans fluid. But, if neither of those fix the problem then what else could it be? The gears don't grind on the shifts but the trans does seem really notchy which I figured is just the way these transmissions feel.

A thunk on take off or coming to a stop or when accelerating I would understand but not sure why it does it when I shift from 1st to 2nd with the clutch pushed in.

In a nutshell: Take off from a stop in 1st, push in clutch, shift to 2nd, THUNK, release clutch pedal, accelerate, push in clutch, shift to 3rd, THUNK, release clutch pedal, accelerate, shift to 4th, perfect, shift to 5th, perfect.

Any ideas or experiences with this? Thanks!

 

Just found an old F150 forum thread where the person had what sounds like the same issue and it was the axle bearings that were shot so I'll check those too.

 

Just remembered that I have a GoPro I hardly use. On a day off when it's actually nice and sunny out I'll attach the GoPro under the truck at various points to see if I can catch the clunk in action.

 

Thrust washers maybe??? How much fore/aft play did the drive shaft have???

 

pawpaw, I didn't check but I will definitely try sometime today. I'll check for both radial and axial play. And I'll see if I can get a video up of just how much that pinion turns before it stops.

 

ok, got a video up on youtube.


No side-to-side play. No fore-and-aft play. Some backlash at the axle but not sure if it's good or bad.

Although not in the video, I did find there is some slight up and down movement right at the transmission tailshaft. Pushing up and down on the drive shaft right there at that big balancer/ring thing on the ds and transmission tail shaft makes a very slight clunk sound. I'm not sure if that's normal or not. And I did notice there is some slight oil spray all over the bottom of the truck in that area.

 

Ok, I've been thinking about this and I'm betting that my clutch isn't moving quite as far as it should and so there's still just a tiny but of positive engagement when I shift gears.

I'm going to try and enlist the help of my wife and see if I can measure how far the clutch moves through the transmission inspection port. It should move about 1/4" to 5/16" correct?

 

In the video, it seems to me there is about twice the rotational play that I remember having in my strait drive vehicles. Maybe a driveline guru reading this will chime in & enlighten us on whats considered max backlash. With the oil misting & verticle play mentioned, sounds like the rear tranny bearing & seal belong on the suspect list too.
Has the tranny ever been run low on lube???
Does the "soft thunk" sound seem to be coming from up front, around the tranny area, or more toward the differential?

 

To be honest I don't think the PO ever checked the transmission oil so it could be low. It's on my list of things to do on the truck this weekend, if my wife let's me.

I'm going to degrease under the truck so I can track any new leaks. Then I want to check the clutch range. Then I'll change out the fluid and take the truck for a test drive.

If the rear extension housing bearing/seal needs to be replaced does the whole tranny have to be disassembled or can the bearing be pulled from the rear while it's still in the truck?

 

I don't know the answer to the bearing removal question, so maybe a manual tranny guru that knows, will answer up & enlighten us on this also.
If the bearing is worn out from low lube level, you may want to consider removing the tranny for further inspection, or at least consider a good flush to get all metal wear debris out before refilling with new lube. Seeing as how service history is at this point unknown & this model manual tranny is known to leak from dry rotted side mounted rubber shift rail plugs & have the tranny lube slowly leak out, I'd at least consider a tranny fluid level & condition check without further delay. Let us know how this turns out.

 

Thanks pawpaw! I'll drain the fluid today and see what I get out of it (how much and if there's any debris).

When I do refill the tranny I'm going to do it from the shifter. Can you see the rubber shift rail plugs from the top with the shifter removed?

 

Not sure if you can access the rubber shift rail plugs from the shifter or not. Here is a link to what the Ford P/N was & what they look like & how to use a hand pump & tubing to pump new fluid in. https://www.ford-trucks.com/forums/5...91-ranger.html
Some folks have been cleaning them up & applying RTV to re-seal them, some have replaced the rubber with metal Welch plugs, some just bought & installed new Ford rubber plugs & others also added RTV to the new plugs when installing.
Here is what they look like & where located on the back side of the tranny shifter casting. Ford Ranger M5OD shift rail rubber plugs - Bing images
If you fill the tranny from the shifter, be careful not to over fill it, as that could cause fluid aeration & more woes.
I couldn't tell from the video, but is this a two piece drive shaft, if so, they are known to cause a "thump" when the splines lube dries out & is in need of cleaning & re-lubing with a new TSB specified PTFE loaded lube.
Did the thump come about suddenly after some event???

 

Thanks for all of the help pawpaw!

- I've only had the truck for 3 1/2 weeks and the thump has always been there so that probably doesn't help much just because of the amount of time I've owned this truck.

- The drive shaft is a one piece unit as this is a regular cab short bed 2wd. It's the 112" wheel base Ranger I believe.

- I was able to drain the fluid yesterday though.

The fluid that drained out was really dark brown in color with a slight tinge of red to it. It smelled like old ATF. The drain plug had what I would call the usual
amount of small metal filings on it from after 130k miles of driving. There weren't any small chunks on it so I think I am safe there. Oh, and there was quite
a bit that came out. I didn't measure the amount that came out but I don't think it would have been considered too low.

During the refill through the shifter hole, I poured until I could hear it dripping from the check hole and then waited for the drip out of the check hole to slow down
a little and then plugged it up.

- Unfortunately no test drive as I had company coming over but I'm hoping to do that today after I tear out the kitchen and bathroom counter tops in our house.

- As for the shift rail plugs I was actually able to see the them from under the truck and I'm happy to report they are definitely not leaking. That's at least one less thing I have to worry about for now. My hands are pretty small and so just by removing the trans mount and dropping it down a bit I would have no problem changing them out when they do start leaking.

- While I was under the truck I found I have a pretty decent oil leak coming from somewhere. The entire backside of the oil pan, bellhousing and front part of the trans are all covered in oil spray. It's definitely engine oil. I've got to get the underside of this thing degreased so I can track these leaks.

 

Ok good feedback, good idea to change the tranny lube & sounds like you got a correct fill on the tranny fluid.
Did you use Mercon V tranny fluid on the refill?
Good to hear the magnetic plug debris was normal & the shift rail plugs aren't leaking & the tranny fluid level didn't seem to have been low. From the fluid appearance, it sounds like it needed to be changed & with a fresh fluid ad pack, you might notice a positive change in the shift feel.

I gotta brush up on my short term memory, as you'd already answered the drive shaft question in your initial post & I'd forgotten it, but anyway that thunk part of the question can be put aside.
The tranny tail shaft seal can be pulled & replaced without having to remove the tranny, if it turns out to be the culprit of the oil misting in that area.

Seeing as how this puppy has 130K, has an engine oil leak, its time for a new/scheduled maintenance PCV valve replacement, in case the old one is clogged up, or sticking closed & causing a crankcase over pressure condition, that's blowing oil out a gasket or seal weak spot.
If it seems that the oil pan seal is weeping, you might try re-torqueing the pan bolts & see if that'll bring joy.
The oil pressure sensor is on the back side of the engine block & is a known leak source, so maybe it also belongs on the suspect list.

With the mileage & unknown service history, maybe the rear main crank case seal belongs on the suspect list too. If its a rear main seal leak & its not too bad & the PCV valve replacement doesn't fix it, you might consider running a brand name high mileage oil this summer & see if it'll slow or stop the leak. There recently have been positive reports around the net from Valvolene MaxLife red bottle/high mileage, Pennzoil high mileage & Mobil-1 high mileage stopping rear main leaks on various vehicles.

With the mileage on this puppy & unknown maintenance history, maybe excessive blow-by from carboned up piston rings belong on the oil leak suspect list too, so a crank case over pressure check at the oil fill cap can offer up insight on that question, as Ford has a spec limit for positive crank case pressure.
More thoughts for consideration, let us know what you find during your scheduled maintenance update resurrection.

 

Ooops, I meant to put that. Yeah, I used Mercon-V ATF.

I'm glad you brought up the PCV because I actually have one here but I've noticed something odd. In 2001-2002 it looks like they used a specifc PN of PCV (EV252). Then in 2003 they list type types of PCV's (EV252 and EV265). And finally in 2004-200? they switched over to a single PCV again (EV265). And so I have in my hand an EV252 and I'm really hoping that's the one. I am REALLY not looking forward to doing the PCV on this thing. Not one bit! LOL!

Ok, yeah, that oil pressure switch was really soaked. As a matter of fact it almost looks like it's actually leaking through the sensor and not around the threads.

Thanks for that tidbit of info regarding the Valvolene MaxLife, Pennzoil High Mileage and Mobil-1 High Mileage. I purchased a proper Motorcraft oil filter and some oil but don't remember what brand of synthetic I picked up. I'll check that later once I get home.

And I'll definitely check for blowby.