High pitched whistling sound in front end when in reverse

Hey all,

Im a new member and recently bought a 03' tacoma TRD off road, auto, 3.4L 166k

Truck was parked on a incline, started up and shifted into reverse, and started backing up. all the sudden I heard a strange High pitched whistling sound coming from the tranny or diff. It sounded like a bearing that was spinning super fast and then slows down and stops. Truck drives fine and shifts perfectly fine in forward gears. Truck only seams to make the noise at first start up backing in reverse.

Any ideas to what is going on? Just hoping its normal.

thanks

 

Are you referring to the reverse whine that the trucks makes only when going in reverse? If so, that's normal...all Toyotas do it. Especially with the manual trans, it sounds like a toy almost.

I don't have an auto so maybe someone else can confirm that it's the same, but with the manual trans it's a very noticeable whine...gets louder the faster you go in reverse and quieter as you slow down. Every Toyota I've had has done it.

 

I wouldn't describe it as a "whistling" sound though, it's definitely a whine...if you could upload a video clip with sound it would help verify.

 

i know the sound your talking about and its different. it really sounds like a bearing whinding up. like its spining super fast and then you can hear it start to slow down and stop while your still driving in reverse. it wont do it every time its place it in reverse, only when its off and you start it up and place it into reverse and start accelerating. not very loud, dont know if i could catch it on audio.

 

Gotcha, I bet @gearcruncher can help you out with some ideas on what to check

 

Its mocking the 3rd gens

 

thanks, just hoping its nothing. prob wouldnt hurt to do a fluid change also

 

That would be a good place to start, do you know if it's ever had the ATF changed out before? At 166k miles and 15 years, if it's still on the original auto trans fluid it might be better to just drain & fill instead of doing a flush. Doing a full ATF flush on a vehicle with high miles on the fluid is risky.

 

there was a stack of maint. reciepts that came with the truck but nothing showing any ATF fluid change. i guess thats a good start. maybe a transfer case drain and fill also

 

Yeah I'd start there and see if it helps anything. If nothing else, it's good peace of mind to do on a newly acquired used vehicle. If I remember right, the t-case and diffs should be changed every 30k. A lot of people push it further than that, which is probably fine if the truck sees only street driving. I put some hard miles on mine though so I usually do my fluids every 25k.

 

10-4 thanks for the advise. It was owned by a 82 yr old gentleman. The truck doesnt look like it has ever seen anything other than pavement. so hopefully he didnt have a lead foot. underside looks like a brand new truck. i checked with toyota and never had a frame replacement. so i just couldnt pass it up.

 

Nice find! I found my 04 a couple years ago out here in San Diego...only 24,500 miles on it and a pristine underside as well. Paid a pretty penny for it though, lol.

 

yeah man i gave alittle bit for this one. of course its alittle bit higher on mileage than i wanted but it was so clean i couldnt walk away. body is almost perfect. the only other thing he did was used 10w-30 in the truck almost every oil change(still havent figured that out) i went immediatly and had it changed with 5w-30 high mileage synthetic. hopefully it didnt do anything to upper cyl due to thicker oil

 

Oil shouldn't have made a difference. If you have a go pro or a cheap knock off you can mount it under the truck in a few places under the truck to help figure out where the sound is coming from.

 

hey thats a great idea... will def post as soon as i can get up with my buddy. He just bought a go pro.

 

I could be the rear brake shoes still contacting the drum (not retracting). Pull the drums and check out the return spring, and lining thickness.

 

Some good advice from
eon_blue

I would drop the transmission pan and inspect what kind of contamination you have sitting on the magnets , clean the re-usable filter and put the pan back on and re-fill .
First thing you should check before you drop the pan is the trans fluid level . Make sure the fluid is full when the transmission is warmed up by removing the dipstick with the engine running in park . Is the fluid full ?
The reason we start here is because out of all the gearing inside the transmission , " Reverse " uses the most pressure .
It,s not uncommon for a cold transmission to make noise in Reverse when the transmission is warming up .
When the trans first starts up , the transmission pump is working extremely hard .The transmission pressure regulator is working crazy hard . It will actually buzz like a very very loud bumble bee
The pump has to take that cold , thick fluid and charge the torque converter , then as you select reverse , the pump has to supply cold thick fluid to the most demanding circuit in the transmission .
At 166k and no documentation of a transmission service , I suggest a pan drop .
Next suggestion is to back into the driveway on your way home rather than starting up and selecting reverse when the trans is cold .
Pumps make noise , pressure regulators make noise and torrington bearings make noise . Start by checking the fluid level and then post back your findings .
https://www.tacomaworld.com/threads...sions-write-up-your-4-speed-automatic.325531/

 

Glad I found this post. Years ago in extreme cold, I used to warm up the truck in neutral. Does it make a difference with Toyota transmissions? The other thing is what are the Operating temp. parameters for this transmission. Thanks in advance.

 

Hey there fellow Canuck . Hope you are enjoying this heat wave as much as I am LOL

Transmissions are cooled and heated by the engine .
With this said , transmissions are designed to operate efficiently at or near the same temp as the engine runs ...170 degrees is optimal for best shifting and fuel efficiency .
Warming up in neutral ? There are no hydraulic circuits inside the transmission that are used when the transmission is in neutral .
On the other hand , older Chrysler vehicles use to warm better in neutral because hydraulic circuits were being used
You are better off warming up in park . Its safer and the same friction occurs inside the transmission wether you are parked or in neutral

 

Yeah, another "surfs up" morning @ -29C. Guess warming up in neutral only applies to my old Buicks. So, operating temp. range doesn't change much from old school & now.