Crazy knocking on hard acceleration

I just changed my rear diff fluid and greased all my driveline points. When I began driving I noticed it aggressively slips and shakes the whole truck initially off the line. What in the world is going on? Could this be too much grease on the driveshaft or a problem with changing to rear diff fluid? Is this possibly a transmission issue too? Although it feel like it’s coming from the back near the rear diff

 

I did just change the transmission fluid too. What it feels like is the driveshaft spinning but not catching a gear. Not super mechanically inclined so I just have no idea where to go from here.

 

Do you have a PreRunner with a true LSD? Could be you need more friction modifier. But a diff is pretty simple and shouldn't really slip. I'd suspect not enough transmission fluid or something related to the transmission first.

 

I believe I don’t have an LSD, tires spin opposite when on a lift. It’s just weird to me because I changed the transmission fluid a few days before my diff and it only started after working on my diff. I removed the driveline to inspect it but put it back. I’m just baffled with what this could be and have no idea if it’s something that needs to be urgently looked at.

I’m supposed to be driving to Alaska from Utah here in a week so I’m a bit worried.

 

What did you use for fluids?

Are you sure you drained the trans and refilled it to the correct level? ATF fluid needs to be checked with engine idling on flat ground and trans up to temp.

What was the condition of the diff fluid and the magnet on the plug? How much metal? Any large pieces?

How may pumps of grease for the slip yoke on the DS?

Name 5 General Mills cereals without cheating.

*Saw you removed the entire DS but didn't explain how. If you separated pieces, is the phasing correct again?

 

^LOL

Also, do you have a 2-piece driveshaft with center support bearing? What shape is it in, and did you put it back exactly where it was? And when you took the driveshaft off, did you mark it and put it back on exactly the same way? Vibrations can come from any of those things. The slipping -- only the transmission can cause that.

 

HAHA last question threw me off

drained the transmission, super watery and black fluid (sucks because I got it rebuilt last year) checked level about a dozen times (cold and hot while idling) I used dexron IV/75w-90 gear oil/and “transmission fix” additive. The magnets on the trans were super dirty.

the diff looked dark but not bad. The magnet had nothing on it. Filled it with

$28 Mobil 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

Mobil 75W-90 gear oil.

I have no idea what a slip hope is hahah so I couldn’t tell you.

(Lucky charms, pops, trix, chex, and rice Krispy)

 

I wasn’t the one that took the driveshaft off, but my friend who’s a mechanic did so I’m assuming he got it back in the right spot, any way to inspect that? I’ve gotten the driveline rebuilt twice in the last two years so the u joint looks good.

 

You can take a few good photos and post them here. We can look.

Have you jacked up the rear end since these issues began to see if things spin easily like they did before?

 

this transmission description sounds super suspect. What is up with that? Rebuilt where by who? Where they at these days because it sounds like they just dumped in a bottle of Lucas and told you it was rebuilt.

 

As long as they didn't clean things up too much, it's usually pretty easy to see if the center support bearing is off, and it's only 2 bolts to loosen a bit, adjust, and torque back down. But again, that's just for fixing a vibration. As far as the ends of the driveshafts, unless they marked them and the marks are still there, no way to tell if it was put back the same.

Still, a slip and a shudder sounds like transmission to me. I'm not a big fan of additives, but they seem mostly harmless and mainly just condition seals.

I'm not sure Dexron IV is the right choice. If it takes Toyota T-IV, that does not seem to be the same and there are other types recommended. This might be part of the problem. I would validate that what you used is compatible (I see that Dexron VI is compatible, but not finding any info on a Dexron IV).

 

Okay I attached a gopro to the undercarriage and found some pretty interesting evidence. It's clearly something to do with the driveshaft, you can see it moving EVERYWHERE...

Here's a link to the video!
https://youtu.be/cjAzRvJxdIw

 

"Rebuilt" it here in Salt Lake City at Tip Top Transmission. Took them a good four weeks LMAO. I did that in April of 2022. I have a TON of weight but that shouldn't have destroyed it that fast in my opinion. I had my driveshaft rebuilt just before that but had to get it rebuilt again this December because it was way out of balance. I'm curious if there is something else that could be causing all these failures. Again, I have quite a bit of weight, but not I don't think it would create such failures that fast. I drive to Alaska about twice a year and do put a lot of miles on it but never had any problems on the road.

 

I will add that I think my description of "slip" is a little off. I don't notice shifting issues, in-fact, it shifts very well. After taking the video it's totally more of a balance issue. I'm not sure how to correct it.

 

got dam. er...sorry. Holy shit. How does this happen so often to you.

 

Sure looks like the front half of your dirveshaft it bent. I'd get it retubed and balanced.

You'll also need a new carrier bearing.

 

You're joking... this would be the third time in two years that I've had to get it rebuilt...

 

Hydro locked my engine too and had to swap it out

 

That carrier bearing is definitely shot, I'd start there. There's a staked nut that you'll need that is a dealer part, but it is cheap. But you might want to get that driveshaft checked and balanced or it will just tear up the new bearing.

 

Okay so why is my driveline failing this much? This is the third time in two years. Could something else be faulty that’s causing this!?