Help diagnosing possible tranny problem

[Mike McKinney]

Here's the story. About two months ago I had my transmission service, replace fluid, adjustments. I've recently started hearing a rattling type sound, like ball bearings in a can or something loose and rolling around. It's mostly prominent when stopped, I hear it a bit as I accelerate but seems to go away. It will also come and go, one drive not there, next it is. I climbed under my truck with engine running to see if I could locate source but I'm not totally sure it's coming from tranny, sound is hard to pinpoint. While I was under there I also noticed a small leak seemingly coming from the junction where the driveshaft mates to the tranny, there is a small puddle of fluid under truck and some splashed on underbody.

It really sounds like a bad catalytic converter but I just can't be sure, the leak and recent service makes me lean towards something with tranny. I've checked the heat shields and skid plate, everything is tight, even tapped on exhaust etc. to see if anything rattled but seems fine. The fluid level is fine and it's shifting fine, no change in that. So my questions are:

1. Is there a better way to diagnose before I take it to a shop??
2. Any ideas on the leak?
3. Should I have a MIL, there is not one on now?

Any help to narrow down my problem would be hugely beneficial, thanks in advance.
Mike

[Wreckonized]

i am not 100% sure if this is related to your problem. But i have noticed some rattling sound too.this is after i have installed my new tires and rims( with skidplate and all mudflaps off. it seems like my situation is very similar to yours, the sound comes and go, sometimes its right after stopping at a light/ stop sign, sometimes it is right after i hit the gas from a stop. it sounds something like a metal rod rattling.

if anyone could help or had a similar situation but got it fixed please reply to this thank you =D

[tundranigado]

Folks - check the posts/threads (and there're lots of them) on "diesel" sound/chatter in this forum.

If you have the same problem then you're not alone.

Lots of Tundra owners are having "diesel chatter" when idling/accelerating. It sounds like a metal rod banging on a hollow pipe synched with your engine speed/rpm...akin to a Cummins diesel truck coming up the driveway. It typically occurs when ambient temp is low/the truck is cold, and accelerating at low rpm/low load. It also typically goes away once the engine is fully warmed up.

I have the same problem with my 00 Tundra V8 with 145k miles on it. It is common...most dealers will dismiss the noise as normal...many speculate on the cause...from carbon deposits on the pistons/valves....to "piston slap".....to cracked exhaust manifolds.

I've had the cracked manifold experience before on a 97 corolla...same type of noise issue ...replaced the manifold/gaskets..no more noise problems.

On the Tundra though, I find using 10-40 synthetic oil in summer, and 10-30 in winter does the trick.....a can of Chevron FI cleaner every oil change helps too......in the end I blame cheap gas (Costco) for the problem....

Hope this helps.