Weird clunk going slow up hilWhat's the best remanufactured Transmission at a reasonable price

So I've got a 2008 Tundra 5.7l 4x4 crewmax. I've recently been having a weird issue with it while going up steep inclined hills at low speeds. If I start to give it some gas then let off it seems to hit a sweat spot where it wants to shift between 1st and 2nd pretty hard. No loud bangs or slams, but unusual shifts forsure more of a jerk. I took my brother who is a certified mechanic on a drive and he almost thought it felt like a misfire until I got it to do it over and over again and he said it definitely feels transmission related. Granted he isn't super knowledgeable when it comes to the internal workings of the Automatic trans so he didn't have a awnser of what he thought it was. I noticed it this week at work on a client's steep narrow driveway at work where it felt like my rear tires slipped on some dry leaves, then caught traction. But when I drove up again really slow and backed off the gas a little then got into it again it did that jerking thing again. My first thought was maybe my U-joints because I knew I had a bad one which needed replaces. So Me and my bro replaced said U-joint in hopes the clunk/jerk would go away... but it didn't. And that's when we went on the test drive and he said he thinks it's the trans. So any ideas on what that could be? or where should I start shopping for a new transmission so I got a back up once this one shits the bed?

 

First thing is first, service the transmission. When is the last time it had it's fluid changed?? Is the fluid at the proper level? You can also request a blackstone lab analysis on the drained transmission fluid. You may want to hold off on draining it until you receive said container and follow their instructions. Get an inside look on what's going on.

#2 This may be a long shot, but since the transmission shift is mainly based on pressure, check out your Throttle bypass hose, the one that dives underneath the throttle body, but curves into the intake manifold. Mine was damaged for a while and would have the transmission shift funny, since I've changed it, transmission has shifted fairly better, but I recently found a leak out of the drain plug which has gone back to intermittent hard shifts every once in a blue moon.

 

Thanks for the quick reply. Yeah that's what my brother told me. Get it serviced. Which I just had oil change 2k miles ago and it was good on level and still good color. Also he said to have Toyota fluid put in it, sometimes they dont like other brands. I just bought the truck from the dealership though and they were kinda sketchy so who knows what they put in. Also it passed the dealership " inspection" with front & rear axles leaking, steering rack needed replaced, passanger catalytic converter, u-joints, All have been replaced since I bought it 3 MONTHS AGO. Of course cam tower leaks but that can wait, it's not worth the money to fix when no drips in my driveway yet. And today it wouldn't start but I replaced the fuel pump relay and voila it started right up so that was cool. I love the truck don't get me wrong but man it seems to be one thing after another. I'm just throwing money at this thing. Hopefully soon all this stuff will be fixed and I'll have a truck i trust to be reliable. I'm about to start stock piling all the major components for backups lol

 

lol. well... I haven't had a need to replace much. starter and water pump so far. Got most of my transmission issues resolved before the warranty was up, long ago though. I do think these transmissions are misunderstood, even by Toyota...

 

I would look hard at the rear leaf springs before condemning the transmission. The engine makes good torque, first gear is reasonably low, and you have low gearing in the rear axle. Add a spring-over axle and that’s a recipe for axle wrap.

Loading the rear leaf springs like you are doing very easily induces axle wrap between the 1-2 shift. As you apply torque to the rear wheels to rotate them, the axle housing and springs have to counter that rotational force. This twists the springs and stores up energy; when the transmission disengages one clutch pack and engages another clutch pack or sprague, torque is discontinued momentarily to the rear axle so that stored up energy in the springs starts to release and rotate the axle back in to the resting position. But when the next gear is applied, torque is restored to the rear axle, tires, and springs. This happens very quickly and often produces a thump/clunk.

My truck has done something very similar from day one.

 

Not only that but the spline shaft slip joint in the 4x4 model's rear driveshaft tends to stick a bit when under torque, even when new. It's possible it's wrapping the axle and the slip joint holds it there until he lets off the throttle, then it lets go and the axle pops back all at once

 

^This, too.