Gas moving around in tank - feel thumps

Has anyone else noticed when they're close to a full tank they feel the gas moving forward and backwards causing thumping sounds coming from the back? I've owned many cars and never experienced this before.

 

dont think its the gas you are feeling. probably driveline "lash". have you greased your u joints? they come dry from the factory and i noticed a big difference in the thunk immediately after letting off accelerator after i greased mine

 

Could be the fuel inside moving? Especially when it's full

 

Mine did the same thing with a thump a second or two after coming to a complete stop. It was at the dealer for a week and they spent about 20 hours trying to diagnose it before telling me it was fuel sloshing and giving it back to me. It seems like a (somewhat) logical explanation because it only did it around 3/4 tank and I also noticed my loaner Tacoma starting to do it as I was driving to return it, but it's a poor tank design if that's the case.

 

Nope. Sounds like something could be loose.

Edit: Sloshing or thumping? Thumping... no. I haven't really heard sloshing either.

 

My driveline clunks when rolling to a stop at times. Reminds me of a 1989 Ford Aerostar van my trailer park uncle owned.

 

I agree if it is the gas tank it's a very poor design! I haven't greased my u joint, is there a grease fitting for that? I don't notice it nearly as much when my tank is low on gas. More noticable when it's full.

Fwiw, only have 6,000 miles.

 

if its a 4x4 there are 5 in the 2 driveshafts. i thought my truck was broken because it always had a clunk the moment i stopped accelerating. like a constant love tap but there was nobody behind me. found dry u joints were the main culprit. they caused fair amount of drag on the drive line and it caused a lash effect. even if it isnt your main issue, it cant hurt to hit em with grease to rule em out

 

Just an FYI, they changed the joints in the rear shaft to not be greasable sometime in June 2016. Based on OP's build date, he may or may not have the ability.

OA

 

Sometimes they don't get the spare seated right and that will cause some 'noise'.

 

This was the case on the '15 Colorado I traded off.

OP just reach in the fender well and push on your spare. Maybe all you need is to raise or tighten the what-cha-ma-call-it.

 

Great suggestions, thanks guys! I'll check and see if I have fittings and my spare. Now that you mention it, I recall my wife's Rav4 had a similar problem caused by a loose spare.

 

If it doesn't do it with half a tank of gas then it's the gas in the tank. Mine does it too.

 

Mine does this too, stop, pause, thunk.

 

This is exactly how it goes, stop , pause...thunk! What have you chalked it up to, gas?

 

I highly doubt it is gas. I'm not sure what it is at the moment. I'm due to regrease my u joints, so I'll see if that has any effect on it. I've been noticing the thunking a lot more lately than before.

I've also had my rear differential replaced by Toyota a few thousand miles ago so that could be a contributor. Im also pretty sure the driveline angles have always been slightly out of spec due to the slight rumbling that happens when I am coming to a stop (maybe there is some sort of binding and release?).

Also a possibility none of it is related and it's just inherent to the design.

 

This sounds exactly like axle wrap, which the 1st gens were plagued with. Mine had the problem and I went round and round trying to fix it. I only managed to lessen to the degree of "not too annoying"

https://www.tacomaworld.com/threads/goodbye-axle-wrap-mod.108316/

http://www.yotatech.com/f2/tacoma-axle-wrap-re-visit-64698/

 

Hey Joe(ReconRider46), I have a 17' TRD Offroad. After listening to your description, I'm convinced it is your fuel sloshing around. I have also noticed this on my truck when my tank is 3/4 of a tank full to completely full. I know because when I stop, especially when pulling into my garage, I feel and hear the thump you're talking about followed by the faint sound of gas sloshing around. If you have your AC and radio off you'll be able to hear the sloshing after the thump if everything is quiet. If it was something else, it would do it all the time, not just when your tank is full. No worries buddy. I noticed this on my 2013 Tacoma as well.

 

Initial thud is from the momentum of all the fuel hitting the front of the tank before it settles down when you stop. Not as noticeable as your fuel level drops.

 

I get the same thump noise too and its from the gas in the tank. Usually happen when to tank is close to full.

I know it's the gas because when I pull into the garage late at night (and it super quite), I can hear the gas moving in the tank coincide with the thump.