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TH-400 Fluid change. Lots of Material - Rebuild needed ?


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Hello,   TH-400 trans. It was rebuilt by a shop in 2016 , new torque converter and all. Trans has maybe 4000 miles on it and there is a lot of slugs in pan. Prior to putting her away for winter I heard what sounded like noise from the torque converter a couple time when driving.   So do I pull her and have rebuilt ? Check out the pics . 

    TH-400 trans pan 2.jpg

TH-400 trans pan.jpg

TH-400 Filter.jpg

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Was it still shifting ok? And what kind of noise? I have seen worse than that but they needed rebuilding.  If it was mine and just had plans for around town type driving I'd change it and give it a try.  Also has the fluid been changed since it was rebuilt last time? I guess if you have any long trips planned it may be a good time to rebuild again while it's down for winter. 

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That isnt metal, it looks like clutch pack material. I wouldnt say it needs rebuilding, but a rebuild certainly wouldnt hurt. A 400 is pretty bullet-proof in the transmission world. 

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IN 2016 I was pulling back into the driveway and I heard what sounded like change (coins) in the converter. It was really bad so I had to pull the trans and get it rebuilt. I belive it was the converter that blew. I heard that same noise for only a few seconds on three different ocasions last times I had the car out. The drain plug was  covered at least an 1/8 of an inch thick with metallic material I thought was just clutch pack. And I know there is some clutch pack that gets worn off and leaves a film. I just thought this was pretty excessive in the pan and in addition to hearing the noise I am concerned.

 

Thanks guys . 

trans 1.jpg

trans 5 .jpg

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I’d say yes. You don’t won’t to be out driving something you know is going to leave you stranded. Now is the best time since the car is parked. You will never feel comfortable knowing that’s like that. IMO. 

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43 minutes ago, Andy's Auto said:

As Bruce Buffer would say. " It's Time"

I guess I would trust Andy's opinion on this. Its been years since I was working on transmissions and he does this stuff every day. Have never met him in person but is quite knowledgeable from all the help he's offered over the years. Some day I'd like get down to his shop and meet him.

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If it was just the sediment in the pan (which everyone agrees is pretty normal, but sure looks like a lot since a 4K miles rebuild), I would probably go with it, BUT....if you're hearing noises similar to the ones you heard in the past, it's time to take it apart and see what's going on I think.

Did they flush the lines/cooler the last time it was rebuilt or did you remove & bring the trans to them?

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I stand corrected about the need for rebuild. I only looked at the pictures and read the thread header and failed to read the text about noises. 

 

So I would say with the material and secondary issues, aka noises, I recommend you rebuild it. 

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Quote

 

I pulled the trans and brought it in. I did flush the lines and cooler with parts cleaner and air hose when she was out. The sound happened when the car was in drive, but I was stopped with foot on brake. Once in a parking lot and twice at stop lights. The best way to describe the sound would be like coins in a coffee can, very briefly only  for a couple seconds then nothing. It's of those sounds that stands out when you know your car. Of course my wife looked at me like what are you talking about. ...The magnetic plug was caked with material 1/8 inch thick, I wish I took a picture before I cleaned it. The clean spot in the trans pan is where i wiped it down to see how thick it was.. Its street driven. Yes I beat on it and shift it a lot but not a 1/4 mile car. It just seems like a heck of a lot of material for 4000 miles..  

 

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I agree with you that it looks like a lot of debris for only 4000 on the transmission.  Looking at what I would consider CHUNKS I would lean toward a downtime winter transmission rebuild.

rob

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Just curious, did you check the flexplate to crankshaft and flexplate to converter bolts? Those suckers can sure make metallic noise if not properly torqued. 

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I had to replace starter mid summer. I found two of my torque converter bolts had backed out. So I removed them cleaned them . Then I Loctiited and tourqed them down. That was prior to me hearing that noise.. Its possible the noise I heard was not the Trans, but it sure sounded like what I heard when it blew back in 2016. There are no chunks in the pan. Not to be a broken record But is just so much fine material for only having 4000 miles ...

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No transmission should look like that with 4,000 miles, certainly not a TH400. Time for a rebuild-including the torque converter.

What engine & power level?

Who did the rebuild in 2016 and who's doing it now?

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I am not sure of the power level of the engine.  The build is listed belowI attached the cam specs.  Roller cam and lifters. 

The rebuild in 2016 was done by a trans shop in area. He actually rebuilt it 20 years prior to that and it lasted. If I have it rebuilt I am looking at different shop, I found one kinda in the area since they actually list th400's.   https://www.proformanceracingtransmissions.com/contact.   I had the engine rebuilt in 2014 and only upgraded the torque converter stall at the time. The new B&M TORQE CONVERTER I installed is what went out on the trans in 2016, coins/Marbles in a coffee can all the time. Thats when I had the current trans rebuilt and new torque converter. I also added a GV overdrive in 2019 that is a total separate unit.

Thanks 

 

Engine build and Cam Specs : 

Engine Cubic Inches:    468

Compression Ratio:      10.1

Intake Manifold Brand:  Edlbrock AIR GAP RPM

Cylinder Head Type:     Brodix race rite oval port

Intake Valve Diameter:    2.250 in.

Exhaust Valve Diameter: 1.880 in

Fuel Pump:      Mechanical

Transmission Type:     TH-400

Header :     1 7/8"

Rear End Gear : 3.73

PRO-System 4150 Carburator

.............................................................................

 

Cam card.jpeg

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Looks like a hydraulic cam. Bullet is awesome. Let's say you're making 475-525 HP and plenty torque.

Have the new shop build the unit to handle 700 HP and you should be well set. Fully rollerized and maybe a 300m input shaft.

I'm sure they can build a better torque converter than an off the shelf B&M unit. Have your weight, cam, rear gears, GV ratio and tire size for them to get it right. If you're still using the stock in radiator trans cooler, nix it, they can actually heat the trans fluid. Get a good stacked plate cooler to sit behind the grill.

 

 

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After you get the unit back, before you install it, install the dipstick tube and drop the pan.

The dipstick "full" mark is exactly at the pan rail. Make sure your stick markings match it.

TRANS dip depth.JPG

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When I had my th400 rebuilt he cut open the converter and put all new bearings in and added some extra bearings that were not there from the factory. So I got to keep my original converter with internal upgrades. I requested all old parts for the transmission and converter he gave me everything including the old gaskets. Not that I know anything about transmission internals but it was my way of checking to make sure I got a full rebuild. 

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The B&M converter was the culprit in 2016. It was replaced by a custom convertor they had built by another shop for them and They rebuilt the transmission.  I don't think they did it wrong,  I just don't think it was built as heavy duty as it should have been,  Or I used wrong fluid.  I was using the 4 core Radiator cooler along with an external trans cooler mounted in front. I also have the deep Aluminum trans pan. I do not have a trans temp gauge. Fluid type maybe ? I was running "Valvoline DEXRON-V1  Full Synthetic"...

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I'm not so worried about "metallic dust" and the silt of friction material in my pan, but you have "pieces" in there as well. What is going on?

I would be worried too.  Something isn't right....

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Finally talked to the original builder. He said shouldn't be an issue the fluid I used was fine.  I forgot to mention that I also have a G/V overdrive witch works really well. But when in O/D and coming to a stop it hits, downshifts a little hard only with the O/D when I have it on.  He said adding  the O/D  is harder on the Convertor?  Think Im gonna pull it and have it looked at.  At this point not sure if it will be with his shop or another. They are reliable but there is a shop right by them that does racing transmissions. Not that I need a racing trans but maybe that would bt the better option.   

 

Thanks guys 

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