I'm having more headaches with the car lately, grrrr!

My TH350 is driving me nuts! It pukes fluid out around the where the kickdown cable attaches, pretty much every time I park it.
Weird thing is that it doesn't start leaking though until it cools down. It doesn't leak when it's running, nor when you first park it. Come out the next morning though and there's a puddle under it.
Since I've had the car down a couple days re-installing my intake, it has left a nice big puddle of tranny fluid on the floor.
When I look under there with a light you can see the trail of it going from the kickdown cable to the edge of the pan, where it's dripping off the front corner of the pan. FWIW the kickdown cable is installed but not attached to the carb. I just use the ratchet shifter when I want to downshift.

Also, the trans behaves strangely, under part/light throttle, ONLY while turning or going around a curve, it will slip. It's kinda like it tries to downshift or go into neutral but doesn't quite make it, more of a 'slipping' behavior. The engine will rev up, then it will 'engage' again and be fine. It doesn't happen going straight, only in curves.
Also when it is cold and I first try to pull out of the driveway, sometimes it doesn't want to engage into gear.
I've re-adjusted the shifter linkage, I don't think that's the problem.
WOT, it works just fine. Fluid level is high if anything, it's definitely not low on fluid.

Any advice, besides hauling the whole oil burning, fluid dripping heap of junk to the crusher? ;)

thanks,
Brian

I had the EXACT same problem with my TH350 when I installed it, First off I had to replace the seal on the cable ( hat shaped rubber guy ) by removing the kick down cable from the tranny, and running it through the seal, then reinstalling it. Second, The cable, as I found out from a neighbor who works as a heavy mechanic at a local chevy dealer, MUST be hooked up to the carb and adjuted correctly for the trans to work right. Apparantly it does more than just affect the down shift. If adjusted wrong your tranny will do exactly what you're describing yours does without it being hooked up.
Hope this helps, good luck! ( the cable bracket should be available at any auto parts store that sells chrome goodies.

I've heard conflicting arguments on whether or not a TH350 needs the kickdown cable hooked up in order to operate right. Some say it does, some say it doesn't matter.

I agree about the detent seal (thats what it's listed as at the dealer). It will leak as described.

Hey 68SSCloner, where did you get that kickdown cable seal??? I need one desperately and can't seem to find it. All the shops by me say it comes with the cable (of course I don't need the cable) and other tranny shops say it calls for an "O" ring (But my mechanic took the seal out and it's definitley as you say, "the hat shaped guy") Where can I get it? Help!!

From my local Chevy dealer:
Detent seal for detent cable - 1262475

In case your filler tube is also leaking:
Transmission filler tube seal (top hat later style) - 1259475
Transmission filler tube seal (O-ring earlier style) - 6264902

I've heard conflicting arguments on whether or not a TH350 needs the kickdown cable hooked up in order to operate right. Some say it does, some say it doesn't matter.

I'm not a tranny guy by any means, but I've heard that the kickdown linkage also affects line pressure at WOT, so yes, it should be hooked up. Maybe someone more knowledgable can confirm.

Brian,

A couple of things:

Obviously to prevent the leak you should replace the detent seal.

BUT!! It normally wouldn't make a puddle even if the seal was shot. You pointed out that it doesn't drip when running, or just after parking the car, but only after being parked for an extended period of time. It sounded like a case of drainback to me. When you mentioned that the car won't move first thing in the morning, that pretty much confirmed it. Funny, GM's don't usually have drainback issues but there was a thread about it last week:


http://www.chevelles.com/forums/showthread.php?t=106940

Basically torque converter drainback is the contents of the converter bleeding back into the pan, instead of staying in the converter. The level in the pan then rises to higher than it was designed for, climbing into the center of the trans where whipping parts can froth up the oil, and also climbing the dipstick tube. If you have a questionable seal at, say, the detent cable, out it comes. When you start the car up, and put it in gear, the TRANS goes into gear, but the converter is empty and so there is no fluid coupling between the engine and input shaft, so the car just sits there.

Anyways, that is why it leaks, and why it doesn't move first thing in the AM, betcha dollars to donuts.

Why (or from where) is it draining back? That's another question, but you have other issues in addition. I think you need to consider going thru the trans...your problems seem small now but will get worse soon. If it really is slipping it won't last long. Slipping is, well, the beginning of the end.

As a note you MUST keep an eye on the fluid level. With drainback your converter is empty on startup so the pan (and dipstick) level is artificially high. Once the converter fills up as the car warms up the "extra" oil is sucked into the converter. Now if the trans had just the right amount of oil in it to begin with, leaked on the floor, you started it up and checked the level, you would find it ok or maybe a touch high. But in reality the total oil in the trans plus converter is NOT ENOUGH, and when the converter burps out the last of it's air ten minutes or so later the pan level is now low, and the trans might be starving for fluid, which is why you have problems on corners. You gotta keep the fluid level up, and check it only when fully warmed up and the converter has refilled. Unfortunately, it will continue to leak fluid on the ground until the seal is replaced. If the seals are all good, you will find the oil climbs the dipstick halfway to the top. Remember when you said the fluid level is "high, if anything, definately not low on fluid"? I think the drainback might be fooling you.

Drainback will continue until the root cause is found. It might be something simple, but in my experience it is hard to find. I have had it caused by a badly worn front pump bushing, and that is NOT accessible without pulling and dissassembling the trans.

You might be able to limp along for an extended period of time. Perhaps if the fluid level is kept high enough your slipping will go away, but you should start thinking in terms of rebuilding the trans.

Sorry for the bad news...what seems like a minor annoyance is probably masking a larger problem. Let us know what develops.

My TH350 leaks at the pan gasket, has been that way a while. The fact that it does not go into gear first thing in the morning is my equivalent of a "fluid level" light. In other words, when that happens I wait 2-3 minutes and it does eventually go, then when I get to work I add a 1/2 pint of fluid and it's fine for another few weeks. I was told by a trans guy that it has to be kept totally full.

Bisjoe,


Next time you experience that shut the car off immed and add the fluid right then and there. If there car engages right away then perhaps the fluid was low, in which case, you should not be driving to work like that, as you are doing damage.

If it still won't engage it's another issue (likely empty converter).

Yes, a trans should be kept at the right level...too full and you whip air into the oil which interferes with the oil's ability to lube the bearings and too low and it will suck air, again, preventing proper lubrication but also maybe not enough oil to compress all the clutches, etc.

Being a 1/2 pint low will not cause the behaviour you describe...the "add" mark is about 1 quart down. Do you mean 1/2 pint takes you up to the full mark again? Anyways, there is a bit of safety margin built in to the fluid level, and its greater than 1/2 a pint.

In any event, you should try and make time to replace the gasket. It's a pita, for sure, but its also not worth wiping your trans out over a piece of cork/rubber.

Dan,

Yeh, I have often done the refill on the spot, but lately I'm leaving at 4:30am and it's dark. It's always the same, check the dipstick and it's just below full, maybe 1/8". Add 1/4 bottle and it's full. That's after I get to work and it's at operating temp. It just doesn't like to engage when cold unless totally full.
It's never needed more than the 1/2 pint and never acted abnormal except first thing in the am. As you said I don't want to overfill it, and since it's only a quart every 3-4 months I have not been in a hurry to change the gasket. I actually had planned it for a Saturday this summer but had my plans changed by emergency Apendix surgery.

Bisjoe,


I'm wondering if being absolutely totally full the Weir level of the pan keeps just enough fluid in the converter? Maybe you have a borderline case of drainback?

It should engage right away, even down a quart...

Whatever works for you!

but lately I'm leaving at 4:30am and it's dark

What? You don't feel like screwing around with your driver at 4:30 on the way to work?!? LOL. :)

That tube is hard enough to see back there when it's light. (53 yr old eyes).

Brian,


so what happened?

well, right now the engine is out of the car after a wristpin walked, so nothing is happening.
I did replace my kickdown cable though, and havn't had any drips from that area since.

ugh...bad month, huh?