Hey guys I’ve got a weird issue I’ve been having the past few weeks.

When I brake suddenly or even not smooth and then briefly try to accelerate the rpm’s go up, I barely move, and the car returns a singular jerking/clunking motion that doesn’t feel/sound great. I make a wincing face when it happens and I’m looking to see what it is.

My initial thoughts are one of three things:

Driveshaft clunk (heard about this before)
Transmission fluid low/needs flush (hesitant of lifetime fluid Toyota advertises)
Transmission is just getting old/worn needs to be redone.


For reference: 2005 V8 Limited 249,000 miles as of yesterday

Done a great deal of maintenance on this car but never anything transmission based so my knowledge isn’t too solid in that department. Any ideas or info at all would be great!

It sounds like a transmission issue to me, being low on fluid would be my first suspect, I would do the fluid level check procedure and hopefully you find it's low on fluid, if so add fluid until you get the proper level correct and then hopefully it solves your issue.

Back in 2019, rust ate thro' transmission line to rad ( 2005 V8 AWD ) and there was a "gradual" loss of fluid. Did not noticed fluid loss due to all roads to/fro our house are gravel country roads/lanes. Initially noticed the odd clunks from tranny when coming to a stop or starting out. Should have started doing tranny checks, but did not, since noises did not occur consistently. Within days, wife went into town for groceries and car came to a complete stop on return trip just about a thousand yards from our place. Towed it home and found broken line and zero fluid left in tranny pan. A $4200 complete rebuild later by tranny shop ( new planetary gears, bands, torque converter etc. ), and she was back on the road. A costly lesson !
I echo AuSeeker's advice. Check fluid level immediately.
Toyota tranny is a sealed unit with no dip stick to check fluid level. Check must be done from under vehicle. Jack up vehicle for more room if you're a big person. You'll find a 24mm bolt/plug on passenger side ( about 2/3's up ). This is the fill plug. Two other plugs at bottom of tranny pan. One is a drain hole and the other is connected to an overfow tube. Add fluid from fill hole till fluid flow out of this overflow tube. You'll have correct fluid level in tranny ( vehicle be as level as possoble). FSM also says to do this with ambient/fluid temp at certain degrees to be completely exact. Its overkill IMHO unless you 'er doing this work lying on a garage floor in -20 degree weather. Tip: Make sure you can get fill plug open before messing with drain or overflow plugs. Good luck.

Am I glad I stumbled upon this post today, I've noticed the occasional "clunk" in mine, usually if I am coming to a red light and have to stop faster than desired. As soon as I let off the brake, there's a "thunk", which feels driveline related. Thought maybe driveshaft, but I suspected fluid levels.
@4R005 I'm curious to ask, you're saying we can just add fluid on a cold-temp trans until it comes out the overflow? Seems easy enough, I've never owned a vehicle without a dipstick, so apologies for the noob approach.

What you're describing sounds more like the driveshaft clunk, grease the slip yoke until it starts to move from the new grease.

NO, don't just add transmission fluid to a cold transmission and drive it that way, i. e. possibly overfilling the transmission fluid, but it is fine to do as long as you follow up by going through the proper "check fluid level procedure"/getting it up to the correct temperature and then pull the check level plug so you get the level as close as correct as possible, overfilling the transmission can be almost as bad as having the level too low, both can damage your transmission!!

@ TrueNorth4Runner FSM has a very detail procedure for filling and checking correct fluid level. Needs fluid temp to be between 46C ( 115 F) and 56 C ( 130 F)for an accurate check w/vehicle at level. If you want or must have perfect fluid level, I'll suggest to do this. Jack up vehicle ( and level it ). Start engine and let engine idle to warm up tranny fluid. Take temp of tranny case. When it reaches 46 C remove overflow plug w/engine still running. If no fluid comes out, add .4 liters ( .42 US qts.) thro' refill hole. let engine idle for 10 secs and repeat procedure with overflow plug. When fluid comes out and slow to a trickle, install overflow plug, stop engine and you are good to go. If fluid comes out when you first remove o'flow plug after fluid had reach 46 C ( level was higher than desired ), let it flow till it trickles and reinstall o'flow plug and again you'er good to go.
Toyota claims that its WS ( World Standard ? ) tranny fluid is a lifetime feature and requires no drain/refills. This is another discussion/debate for another day.
From my personal experience w/my 05' 4R , when the line broke and drained all the fluid, what I observed from the old fluid ( coating the tranny lines and case ) , the color was still red and in good condition ( at 140k miles). After the rebuild the only noticeable difference came during upshifts in the winter months when the vehicle was first started. The upshifts were quicker as opposed to previous when overdrive did not kick in for another extra mile or two. Most likely the result of the rebuild and not from new fluid.
Yes, as AuSeeker mentioned, low or high fluid levels are not conditions you'll want in one's tranny.

It is on this week's to-do list, for sure! I've been meaning to get to it, have both grease types on hand, ready to go

My Pontiac Vibe determined that that is a lie hahaha. I definitely see benefit to fresh fluid at certain intervals.

Appreciate the long reply, and will give this a whirl, this week!

I have no knowledge if other brands have this sealed tranny feature in their recent vehicle line-ups. My '05 4R and '16 Lexus NX200T has them. '00 Acura RL and '09 Honda Civic don't have them either. All other brands ( Jeep, Nissan, Pontiac and Ford ) that I have owned at one time or other, tranny fluid changes were @ 100k kms. Personally, I prefer open trannies w/dip stick and regular fluid change intervals.

I think there is lots of good advice here for your tranny service, and I hope fluid drain & refill is all you need.
Do you know if your U-joints are regularly greased? Most shops -dealers included- skip over the U-joints during engine oil service and their "Multi-Point" inspection.
Worn out U-joints can be often spotted by switching from reverse to drive with foot on brake and engine at normal idle. You will get a clunk both times.