Vibrations at low RPM's (fixed u-joints and balanced driveshaft) transmission?

I have a 06 tacoma v6 dbl-cab with 115,000 miles. I have never change the transmission fluid. I have heard many different opinions concerning changing the transmission fluid in toyotas.

My problem: I have had vibrations/shaking/shimmy when driving up hill at low RPM's. I have counted the gears when driving up hill and the shaking starts when it is either shifting from 4th to 5th or 5th to 6th gear. (only when it is under 1,500 rpm's.) when it starts to shake i accelerate and the vibration stops, as if i forced it to shift. to diagnose the issue i put my truck in 4th gear and started at the bottom of the hill and no shaking...wtf? it only happens when i leave it in "D"

I have replaced all the u-joints and had the driveshaft re-balanced. Vibration has calmed down but not stopped totally.

Also, when driving at about 45mph my truck seems to be confused... its like it has trouble figuring out what gear to be in... idk it may be me being paranoid.

Can it be the transmission? Can it be the shift solenoids? Can it be my torque converter? Can it be the clutch? Transmission mounts?

(Someone said to change the transmission fluid and it should stop??? The trans fluid is a dark black/brown color... and I have also heard if I have never changed the fluid, do not change it... I can ruin my transmission.)

 

Same damn vibration / shifting issue I have

 

Flush the tranny. Just went through this with my wife's 4runner at 100,000 miles; same color fluid, shudder, and searching. Filled a 5 gallon bucket with fluid and pumped through the transmission until it ran out clean. Now 15,000 miles later, running like new.

 

Are u talkin like a complete change like in that sticky that's a really involved process, or just 3 qts at a time through the drain pan till it looks clean?

 

Dark brown fluid with that many miles you are taking a chance if you change the fluid. As another poster said take it to an independent shop it's not so much stirring up yuck as it is it is taking the facing off the clutch packs this relates to all automatic transmissions not just Toyota. Your shudder could also be the lockup converter it feels like another gear when it locks up but there is no ratio change they can shutter it does have a clutch pack.

 

I will! I am taking it to a local shop today. Thank you!

 

Well if he DOESN'T change it, he sure as hell will grenade the trans. The fluid isn't going to last much longer.

If I were in the same boat, I'd just drain the pan and replace that amount with fresh fluid. Drive around maybe a week and re-evaluate. If all seems fine, do the same thing, re-evaluate. Another week if all is ok, and then do a complete fluid change as described in the tech section of TW.

Then I'd do the same in a year to make sure I got all out the crap that's been building since it should have been serviced.

 

I was a shop manager for a large trans shop in MD for many years it was surprising how long a transmission would run with dark burnt fluid and how quickly they would fail with new fluid. If the OP's problems are related to clutch pack ware no amount of new fluid will fix it, the dark brown stuff most likely is clutch material a good shop should be able to tell him what's wrong just by experience with a test drive if a shop says they have to take it apart first to tell you what's wrong go some where else.

 

I agree with maineah, if the clutch packs are breaking down, new fluid can actually cause more harm than good. That thicker fluid can be the only reason an auto transmission still works and flushing it out and replacing with fresh fluid can cause it to no longer engage (meaning your transmission is officially dead). That's why shady shops used to put sawdust in the transmissions, it'd get them working for a short period of time because it'd thicken up the transmission fluid enough to bring it back to life.

 

So by deferring maintenance on the trans for so long, the OP has got himself a bit of a Mexican Standoff? If he doesn't change the fluid, it will last for an unknown, but probable short period of time since he's experiencing shift quality issues. If he does change it, it's probable he will kill the trans entirely even though the new fluid is needed and has fresh lubricating and other additives in it?

That's not a situation I'd like to find myself in or am envious of.

 

so what about a half and half mix? half old fluid and half new

 

If the transmission is, in fact, the problem, yes. I'm doubtful that the transmission is the culprit here. He's experiencing a shutter at low RPM, high torque situations. The rear engine mounts (which are actually under the transfer case) are known to be soft and could cause the shutter. The carrier bearing is also bedded in rubber which could allow the drive shaft to 'flop around' causing a shutter. There are a lot of variables here, if the truck drives and shifts fine normally, I would think the transmission is fine.

You are right though, it is a crappy situation to be in. We had it happen to a few of our work trucks. We ended up just driving them until they had severe shift issues and replacing the tranny. The mechanic did put fresh fluid in one of the trucks (at the direction of my boss at the time) and it did just what I described, lots of slipping and basically was non-functional.

No clue how that would work, depends on the condition of the transmission.

 

Not even, I was only able to drain about 3 - 4 quarts out and, if I recall correctly, the total capacity is closer to 18 quarts.

 

In the older transmissions if you tow every 30K for a complete flush the newer ones I would go by what Toyota says for "sever service". One of the reasons I said independent shop and a test drive is to let some one drive it that has seen pretty much every type of problem with an automatic if he has an issue with a mount or some thing else they will know it's not transmission related. I would look up a local shop that is a member of ATRA.

 

I had the drive shaft rebalanced by a shop. This situation only happens when i think going from 4th to 5th and from 5th to 4th. When I am going up hill it seems to have an issue when trying to shift. I do not know if it is the mounts. If it was the clutch the RPM's would rev high, which it does not. The truck shutters under 1500 rpm's.

 

Have u not made it to the shop yet?

 

Op did u figure it out?

 

Have I figured it out yet? Ahhhhh NO! I took it to an independent mechanic who works on toyotas and he said it sounds like the torque converter. He said the only way to know is to flush the trany. I am nervous because he also said flushing the trany could destroy it possibly since I've never flushed it before. So it is a 50/50 shot. I have been driving on the back roads with the overdrive off and when I use the highway turning it back on. Haven't had a problem.like I said, It only shutters when I am in the 35-45 range shifting from 4th to 5th when I leave it in drive.

Some one said coil packs possibly?

 

Sme here my fluid looks good I check it this week.

 

No offence to the Toyota mechanic but how many transmissions has he rebuilt? For your sake I would take it to a transmission shop transmissions that is what they do all day long no brake jobs or tune ups just transmissions. A bad converter will not shutter the lockup clutch can but I believe your's locks up in 4th also so that pretty much rules that out. I'm leery of some one changing fluid to fix a shudder. You might stop by Toyota to see if there is a software flash that covers your problem also.