Driving uphill kick/jump/shift problem?

OK, I did a little searching on the forums here and elsewhere, but not getting any results - I think partially because I know not what to search for.

In my 02 xtracab 4cyl 2.7L 4WD, when driving up steeper grades, there is something like a hesitation to shift, then keeping the gas pedal down to a consistent pressure, there is suddenly a "kick" which seems to come from the back of the truck probably from the rear differential. Then it seems to shift into the higher gear and there isn't a problem after that and the hesitation goes away. Now I've gotten used to letting off the gas a little once the resistance starts and slowing of the vehicle happens right before the shift/jump/kick happens, and that seems to alleviate the intensity of the kick.

I checked the fluid a month ago or so in the rear differential and it seemed fine, though this thing has been happening since acquiring the vehicle in Sept 2016. Transmission fluid seems fine, though I'm pondering getting it serviced since I don't know when the last time it was serviced. Bought the vehicle with 80,8XX miles, now past 94,000 miles.

Is this a problem and any clues to how to address the issue? Or is this just the limits of the power of this truck manifesting as this little quirk? The kick seems not normal in any case, though has been "normal" for this truck since I've owned it...

 

This definitely sounds like a transmission issue. Does your truck have a kickdown cable attached to the throttle body?

 

one thing to eliminate is driveshaft binding. Lube the u-joints and the driveshaft extension. If you look at the driveshaft where it bolts to the rear, look towoards the center support bearing and you will see some splines. I bet that these are dry. During acceleration and deceleration the rear end rotates so the driveshaft has to shorten and lengthen... it might be binding and that might be the "kick" you feel, the driveshaft coming unstuck.

on the throttle body there is a cable, the "TV, throttle valve" cable, that goes down to the transmission. There is a little rubber boot that slides over the adjusting screw that the cable goes through. slide it off of the hollow bolt and you will see a ring on the TV cable. That ring has to be close to the open end of the rubber boot while it is installed. Once you see it you will know what I am trying to explain, anyway, you can adjust this by loosening the nuts on either side if the bolt and lenghtning or shortening the bolt in relation to the bracket. This is how the automatic transmission "knows" how hard you are into the throttle so that she shifts later or earlier depending on throttle position... give it a pull and see if the cable is broken inside the sheathing too. Dont go messing with the adjustment too radically this controls the pressure in the trans and if the pressure is too low you will start to overpower the ability of the clutch packs to hold. Go too far the other way and she will shift very hard.

one last test is to apply the brakes slightly... as soon as you apply the brakes the torque convertor lockup disengages.

 

Thanks for the clues guys. I'll try these things when I get a chance and update on the status later

 

I have the same problem ... mine does this just above 1300 rpm, that's when I get the kick and it's hard for me to accelerate past 2500 rpm. Any suggestions?

 

Does it matter if the truck is cold or warmed up?

 

Just cleaned up and greased the driveshaft sections and u-joint zerks, only couldn't get grease into one of them, but it was one towards the front and for a u-joint. Going now to test on the slopes I regularly traverse where the original kick problem was happening to see how this feels and will be back with an update

 

Big difference! Performing scheduled maintenance tasks keeps the truck running well. Imagine that!

Fortunately, I had already planned on doing this lubing of the driveshaft job and already had 2 kinds of grease and a grease gun ready to go, just ran out of time when I replaced the spark plugs one day.

No more kick in any of the spots I normally noticed the kick. Went right up the mountain road, steady at and not exceeding 1900 RPMs, whereas before, it would spike to somewhere around 2300-2600 rpm or so (don't remember exactly) and then kick. Driving on the regular roads I travel on proved that the transmission isn't working as hard as it was before - much more relaxed. Good to see those lower RPMs. Similar to when I did the first oil change since having the truck, guaranteeing that the dealer didn't do shit to change the oil and filter and who knows how long it went on like that. Going to pay close attention in the following days since I do this drive daily and see if lasts.

Next I'll do another oil change, address that rebellious zerk, address a rotted out bracket for the exhaust I noticed while under there, investigate the throttle valve mentioned in the replies, and I've been pondering a transmission flush. Maybe is a good idea at about 95,000 miles, not knowing if or when it has ever been done before, and knowing how much I've pushed it with periodically heavy loads combined with a kicky driveshaft...

Thanks everyone for the input and assistance!!

 

I don't know if it matters/mattered either way. Hadn't had a chance to attempt the road where I was having a problem from a cold start... and as far as I remember, that was the only place the problem was noticeable so far. This is not including how the transmission has calmed down a bit since the driveshaft greasing, which I figured was connected to the lack of sufficient grease, but didn't realize previously that it would reduce the load on the transmission during regular driving as well.

 

On them xtra cabs be sure to check the driveahaft center support bearing too, when they go out they cause all sorts of noise and weirdness.

Glad it was a simple fix!!

 

OK, so the kick came back, but it only happened once instead of the previous 3 times on the same steep road. I think I'll do a little work on the driveshaft. I'm suspecting it might be getting caught on the small chunks/flakes of rust where it should be smooth to when sliding in and out in the 2 spots. Going to grind/brush that out when I get a chance and re-grease.

I inspected the throttle cable. The cable from the gas pedal to the throttle body is pretty loose, so I think I'll tighten that one a bit. I played around with it to see how the cables were responding. I'm aware that the cable on top is attached to the gas pedal and there is tension applied to it when the gas pedal is pressed, so this picture I show is not exactly how it works since I am pushing it the other way by twisting the pulley, but I found it an interesting observation that if I turn the pulley fast and fully, the cable binds up on the rubber boot and looks like this picture. But if I turn it slowly, the binding doesn't happen at all or it just slows the return of the cable. As I tried this action back and forth repeatedly (I made a video) it was like the same experience driving up the hill - the kick would happen HARD if I continued at a constant pressure or more pressure on the accelerator or it wouldn't happen and the shift wouldn't happen either, but if I let off the accelerator quite a bit, the kick would always happen but much softer and then it would downshift, and I would apply the accelerator again to continue up the hill. Anyways, I'm going going to try to tighten that cable and see what happens.



As far as the ring and the boot on the lower transmission cable goes, I checked it and it is very close to flush with the opening of the rubber boot OR it is slightly inside it. I'm thinking that adjusting it so that it sticks slightly out of the boot as per the spec says (0 - 1mm) might help? Trying that as well, might as well do them both at the same time.



Also, in this 2nd picture above, I noticed back where the spring is, there are 2-3 pieces of metal that seem out of place to me that you can see here underneath the upper accelerator cable and above the black plastic round pulley material. What's up with that? Maybe just the tension for the spring?

 

Alright, that's all folks. I did the adjustments stated above, sprayed some PB blaster on the upper cable as far as it goes into the boot and out of the boot, no more problems. So there.