Hello Ranger enthusiasts!

First off, I want to thank all of you! I've been reading and acquiring great knowledge through this forum, as a visitor. I thought it was time to become a member of this great community.

So, I have a 2008 Ranger, 4.0, 2WD, manual transmission with 130 000 km (81 000 miles), bought used in 2016. Since then I've applied myself to learn car maintenance and mecanics by myself (applied on my truck) with the help of ressources such as this forum.

I need your help and guidance with my truck situation:
Since 2 or 3 weeks, my truck has the following intermittent symptom: when accelerating from a stop, the truck hiccups or bumps (slips?) once, when fully in gear. When I accelerate slowly the problem doesn't occur as much, but when i accelerate a bit harder, it bumps once. When it bumps, the RPM's do not move up, as I think it would if the clutch was slipping importantly. It feels like it happens sometimes in 2nd gear, in a much more subtle way. The other day I was driving in 3rd gear at 60 Km/h (37 miles/h) and slowed down to 40 km/h (25m/h) to take a turn. Upon acceleration I should have downshifted but did not (lazy). I pressed the gas, still in 3rd gear RPM's around 1500 and the car bumped like 3-4 times back to back. Downshifting stopped the hiccups.

When driving it feels like the hiccup/bump is coming from under, so i thought about the driveshaft or rear differential. I checked the U-joints, they seem to be perfectly fine. I might have a pinion sceal leak at the rear diff, but I'm still assessing that. I still have to check the rear diff fluid level. I checked the clutch fluid, the clutch pedal itself feels great and shifting gears is easy. Manual transmission fluid was changed at 106 000km (66 000 miles).

Also, OBDII shows no code and all metrics are fine and within normal range.

I thought about removing the driveshaft and applying grease to the slip yoke, thinking that what I feel is actually binding of the slip yoke in the transmission...

My fear is that it could be related to the clutch itself.

Any ideas or suggestions of what could be the cause or what I should do to circumvent the issue or refine the diagnosis?

Thanks!

 

Welcome to the form, officially

The slip yoke does need to be serviced regardless, there is a blue grease that works the best, but this issue usually makes a "clunk" noise you hear it more than feel it

Clean MAF sensor, should be done once a year, also unplug its connector and plug it back in

Unplug TPS(throttle position sensor)'s 3 wire connector and check it for corrosion, then plug it back in, this cleans the connections

Just FYI, this is how you "fix" most sensors, unplug them and plug them back in, lol, sensor's rarely fail but the connections do get a build up on them, unplugging and plugging back in clean them off, this is why replacing a sensor worked, because you unplugged old sensor to plug in the new one, so save your money

The TPS gives the engine computer, a "heads up" that you want to accelerate, it serves the same purpose as the accelerator pump did on a carb, so a hesitation on acceleration could be slow voltage change on TPS or on MAF sensor
MAF sensor issue is usually a "bogging" engine complaint, but can also cause hesitation

 

Following your advice I cleaned the MAF and throttle body. It doesn't hiccup as much as it used to but I can feel that it sometimes want to hesitate. I'm kinda surprised of the results since the MAF readings didn't change much before and after the cleaning. But when cleaning the throttle body I did notice that the TPS has a gritty sound when opening and closing the throttle.

​​​​​​As a next step I think I should test the TPS with a voltmeter to see if there is a dead spot that the OBD scanner didn't get. Does having a gritty sound in itself would be of sufficient concern to justify replacing the TPS?

Thanks!

 

So I cleaned the MAF and took the throttle body out and cleaned it too. Connections for both were nice and clean.
I did check the TPS too. My BlueDriver OBDII scanner presents the TPS data in % instead of volts. But from the results, the % were changing in a continuous fashion, without peaks or crease and in accordance with the throttle opening. It makes me believe that that the TPS is fine but it does feel a bit gritty.

As far as symptoms go, I still get hiccups/bumps when the engine is reving low (1500 rpms) on a high gear for the situation. Ex: If I drive on a very slightly uphill going street, shifting from 2nd to 3rd at 40 km/h, it will significantly bump when I press the accelerator. Bumping goes on until the engine revs are about 2000-2250 rpms. Downshifting also stops the bumping.

On another note, 2 days ago, I had a very bad time putting my car in gears with the engine on, coming from a cold start. No gear was easy nor easier to get in. I had to "plow" the shifter in gear. Once done, it was manageable to shift and drive but it did feel abnormal and significantly different than usual.

I'm kinda thinking that there's something in the clutch assembly like a pilot bearing starting to fail...

 

I'm not sure what you mean by 'bumps'. Is it audible, do you feel it? Lack of acceleration or bucking in the throttle? Or does the whole truck start to die for a second? ie the lights start to go out or flicker. That indicates not fuel but an electrical problem. If the latter, check your ground strap from the battery. Mine looked fine but had a progressively worse problem. Replaced it and now no issues.
The second problem sounds like the clutch slave going bad. It's no fun. It's a concentric slave which contains the bearing so you have to drop the trans to replace if that's the issue. Check your fluid, if the reservoir is low, top it up. Check for leaks, around your foot, under the reservoir, in the line, and finally under or in the bellhousing. There's a little access hole you can peer in with a good light.

 

By "bumps" I meant what would be best described as jerking. So I definitely feel it when it happens. The truck doesn't die, light doesn't flicker, revs do not slip. In the last few days I ran an injector cleaner mixed in the fuel tank and ran through the fuel tank. So far, it seems to have significantly decreased the jerking. I plan on running a second can of injector cleaner.

I did check for short circuits and wire but everything was fine. Cleaned the battery, checked alternator, but I do not remember having checked ground specifically. I'll do that, thanks for the input.

As for the clutch, fluid level is full. I'll check for leaks. I don't know if it's awkward or normal, but it happened only once since my post where I reported the problem (this occurence was really bad). It did not occur again...If something significant occurs again and becomes recurrent, I'll take it to the tranny shop. It's to big of a job for my current setup.

Thanks again!