Pat's converter 'rattle'

[V6POWER]

Installed a 10"/3,200 stall Pat's converter yesterday and upon start up it rattled like there had been sockets left inside. Turned off the motor and checked to ensure all bolts were tight; they were. The converter was seated on the shaft during install and about 1.5 to 2 quarts of fluid were added to the tc before install.
I restarted the motor and let it run, fearing something would break, but the noise went away and things sounded normal. The tc works fine but still upon start up I get a slight rattle for a split second, which then goes away. Fluid level is just above full. Is this rattle normal for the smaller diameter converters?

I am going to call Pat's tomorrow with these questions but thought I would post today for any feedback. Thanks.

 

[turbofrank]

I just installed the same convertor 3400 stall 3weeks ago and last night the same thing happened to me . Noise
went away after 5min sound like a knock at startup and
gunning motor. No time to check out anything yet. Please
let me know when you find out.

 

[V6POWER]

I'll let you know what I find out from Pat's tomorrow.

Converter is working great, otherwise.

 

[Intercooler]

Yea.... let us know. If I can do anything to help also let me know. I didn't or don't get a rattle with mine. Did you guys put any fluid in them when you installed? What did each of you have for stab-depth and were you any of you guys set up for non-lock before installing them?

 

[V6POWER]

I talked to Steve at Pat's and he has never had this problem presented before. One cause he wants eliminated is a drain back problem and he wants me to do some simple tests, see what results I get, and let him know. I need to drive the car and then check the fluid level with the engine off. Note that fluid level and then check the level tomorrow morning without starting the motor, and see if the fluid level has gone up. I also need to start the car tomorrow morning, put it immediately into reverse and note if there is a slight delay before the car moves backward.

CallMeMud--1.5 to 2 qts. were added to the tc before install. I am replacing the stock, l/u converter. The tc bolts only had to pull the tc about 1/4" to tighten it down.

 

[turbofrank]

I have always used lock-up conv. Conv works fine otherwise
can't perform any test for a couple days changing intrc right
now. Let us know results.

 

[Intercooler]

I will check back to see how you guys make out. I take it nothing is busted? Steve stands behind his stuff and will help you figure it out. Can't be worse than a Vigilante

 

[chris718]

drainback is what i suspected but i didnt want to jump in as i have no experience with pats convertors.some convertors will exhibit drainback and the resultant noise on startup.this doesnt mean the convertor is bad and can easily be remedied by installing a late 440t4 cooler fitting with anti drainback checkback in place of the stock cooler out fitting.

 

[V6POWER]

My fluid level was about 1/2" higher this morning and I did have a slight hesitation in reverse before the car moved. I did also have 'rattle' at start up for a second.

I called Steve this morning and he thinks the rattle may be the damper assembly springs rattling because of drainback. He said it is not a problem and will not hurt the conveter but he did recommend that I let the car idle for about a minute before putting it in gear so there is a chance for the fluid to get to the tc.

Chris---Thanks for the suggestion. Steve agreed with what you suggested and also told me if I do that to ensure I use the correct core line and ensure the fitting is flowing the correct direction.

Hope this info helps anyone who may experience the same problem.

 

[V6POWER]

Chris---Where can I get the 440t4 cooler fitting? Thanks.

 

[turbofrank]

Thanks for info as soon as i get my car together i will post results.

 

[jsta6]

so is this a common problem?

 

[V6POWER]

I installed the cooler fitting (GM #8637742) as suggested by chris 718 and I still have the rattle at start up. I will call Steve at Pat's on Monday and see what he says.
One concern I have using the the cooler fitting, besides it not curing the problem, is that it is restrictive (anti-drainback) and I don't know what effect it will have on my high volume pump flow. I should just take it out and install the original fitting that is not restrictive. I will wait to hear what Steve ways before doing that.

 

[77 cruiser]

Sounds like the same thing that's happening with the 4L60-E in my 95 truck. Only lasts for about 5 sec. on startup after sitting overnight. No problems in 120,000 miles.

Jim

 

[Intercooler]

Originally posted by jsta6
so is this a common problem?

I don't think so. At least 10-15 converters on the boards of people that actively participate and these are the first two reported. Hopefully something will be found.

 

[Intercooler]

Any update?

 

[V6POWER]

I still have the rattle, but other than that, the tc works fine. I have talked to Steve again at Pat's and he wants me to try shimming the tc bolts a little to see if that helps. I have not done that yet. Steve said he will give me a new tc in the future if I want. Can't beat that for taking care of the customer.

 

[Intercooler]

I would actually like to see your problem solved for anyone reading later if they have the same thing. Great that they will even give you another if that is what you desire

 

[turbofrank]

Well as posted earlier same problem just blew head gasket 2
weeks ago so another month should be back on road.

 

[V6POWER]

Problem identified!!! We took the three tc bolts out to check the 'stab depth' (which was 5/32) and when we were taking out the last bolt, it was loose. We knew this was not right because we had used lock tight on them and we knew we had them all tight when we installed the tc. When we removed the third bolt, the lug fell off the tc. Not good.

Anyway, bottom line is that the thread depth on this lug was only 0.420 to 0.430 and the bolt (stock bolt out of the D5) had bottomed out onto the tc and pushed the tc away from the bolt, thus putting stress on the lug and causing the weld to separate. Because the bolt was longer than the thread depth, the bolt was not pulling the fly wheel and tc completely together and that was causing the rattle (in addition to the lug) at start up and the clunk when the engine was turned off. We did not check to see that the bolt was against the fly wheel at install because it was tight and there was never a problem with the D5 that the bolts came out of. We have not pulled the tc to check thread depth on the other two lugs.

I called Steve at Pat's today and he is sending me a new tc on Monday. He said the lug thread depth on the converter should be at least .500 to prevent this problem from occuring. Great service from Steve and the tc worked great, except for the rattle.

Incidentily, as a check we put the three bolts (with spacers to take up the slack) back into the tc and started the car and there was not any rattle or clunk.

So, if you have a rattle, you should check to see that the bolts are tight against the fly wheel or that your thread depth is at least .500 or greater than your bolt length.