Auto transmission clunk and possible brake issue

[drmoreau]

Ok guys, first bit of semi-cool weather we've had so far here in Louisiana. Backed out of my driveway this morning and when I put the truck into Drive nothing happened for a few seconds, gave it a little gas and then CLUNK it went into gear.

I've avoided automatics for years due to how often they have issues, but a combination of my left knee bothering me and the stop-and-go traffic I'm often stuck in I got tired of driving stick.

My Runner has 165k on the clock and I really don't know if the transmission has been regularly serviced or not since I just got it a few months ago. I know that with an older automatic it's basically a crap shoot to get it serviced, either you fix the problem or make it worse because the "gunk" was holding it all together.

I'm also still having the issue where my brakes seem to lock up if I come to a stop right after starting up and taking off. For instance: I back out of a parking space, put her in D and take off but have to stop within 5-15ft because someone starts backing out. The truck shudders and it feels like the rear brakes lock up, in fact it takes a little throttle to get going again because it feels like they (or at least one of them) are/is jammed. It's definitely the back because I can do it with the hand brake. I recently had the shoes changed and also the axle seals since they were leaking all over the drums. I was having the problem before that but it was getting really bad, almost every stop if the brakes were even remotely cool. Now I only get it the first time I come to a quick stop if they truck has been sitting for several hours. Any ideas? Related to transmission? I also get a light clunk often when I let off of the brakes (taking off from a stop-light), just a very light little thud that I can hear and feel through the pedal.

 

[Alabamaguy]

Check your transmission mount. I replaced mine (call toyota with your VIN and get the PN# then do some google snooping, got mine for like $30) and my clunking went away. You could see the rubber beginning to separate.

Having similar issues with the brakes. My issues are up front. The front calipers are bad about seizing. Worth a check.

 

[drmoreau]

tranny mount could definitely be a source of clunking sounds, though it shouldn't cause the tranny to be slow shifting into gear.

fairly certain it's not my front brakes since it will do it when I use the hand brake which should just be actuating the rear.

 

[Alabamaguy]

No, It shouldn't do that. 165k shouldn't be a bad trans either though. May just be the cooler weather. Check u-joints and the mount first. See if fluid is burnt. Just normal stuff...start cheap.

 

[drmoreau]

So at 165k with no idea of the service history do you guys think I should get the tranny serviced or just leave it alone?

 

[Alabamaguy]

Check what you can first before you start spending money. If the fluid is burnt and nasty then do a drain and fill. But I doubt you'll need it. The A340 is pretty much indestructible behind a 5VZ.

 

[drmoreau]

good to know that it's considered a really reliable transmission.

 

[jgue467]

if U have the $

So at 165k with no idea of the service history do you guys think I should get the tranny serviced or just leave it alone?

Yes, service it somehow. Either do a complete flush, it can Only help. U can either DIY (search this site for specific how to) or take it somewhere. The trannies that get failures where already on the way out. I only do a couple drain/fills a yr but it has no issues. I have had more than 1 non-toyo tranny saved with a flush. Personally given urs symptoms I'd do a full flush first time. Luck!

 

[LittleCaesar]

Check to make sure your shoes aren't sticking. Also make sure your bellcranks can move.

If OK, then drop the pan and check to see if there is anything besides slag on the magnets.

 

[Run 4 Fun]

Check to make sure your shoes aren't sticking. Also make sure your bellcranks can move.

If OK, then drop the pan and check to see if there is anything besides slag on the magnets.

I agree, pull the drums and inspect your shoes and check to see if your seal is blown again. Your breather tube might be cloggedand blowing your seal which will leak oil on the shoes again.

 

[drmoreau]

Took off this morning and transmission shifted fine, when I got to the stop sign near my house though the brakes felt as though they locked up. The truck shuddered to a stop and then it took some throttle and a "clunk" before it felt like they finally released.

Is it possible that what I'm thinking is the brakes is actually transmission related? I don't know much about automatics, but could it be something to do with how an automatic functions when you come to a stop that's not behaving properly? Something with the torque converter or something else in the transmission?

I feel that it's the rear brakes, because it happens when I stop with the handbrake, but the shoes are new and the axle seals are no longer leaking. I don't know much about drum brakes but what else could be causing them to lock up (and not want to let go) when the truck is cold?

 

[jgue467]

OP - are we talking about a quick stop or a gentle longer one? On quick stops, the rear end will lift up causing the driveline to compress, then held in place by the brakes, then released when you release the brakes causing the clunk when the driveline snaps back into place. Has the driveline been lubed regularly?

Some more background info here: http://www.toyota-4runner.org/3rd-gen-t4rs/110279-driveshaft-lubrication-4wd.html

 

[drmoreau]

The slight clunk that I feel when letting off of the brakes (as opposed to the shudder upon stopping when the truck is cold) seems to happen at some stops and not at others. It could very well be the ones that I'm coming to a quicker stop, I'd have to pay more attention to which types of stops it happens with.

I had considered that possibility, that it was the driveline de-compressing. As for lubrication, I brought it to a lube place to get the driveline lubed and they said that there were no lubrication points they could see, mine is RWD, not 4x4.