Jcpstrat

This is a continuation of the thread “TH400 2nd Gear Shift Problem” at:

https://www.corvetteforum.com/forums...t-problem.html

Just got TH400 back from being overhauled. It had serious problems.

First the Torque Converter was not stock … it had been cut apart to weld the internal fins and then welded back together & balanced. It also was bolted to flexplate with 6 bolts not 3. Shop recommended trying to get it reconditioned and sent it out but apparently a bearing in Torque Converter failed and it was tearing up converter so I went with a new HD TQ with furnace brazened fins. Pressure plate in tranny was fractured into pieces but still held together with I think a snap ring.

One of the clutches had no clutch material left on it … just had metal on metal. I’m just surprised the car ran at all. Good call to pull it.

Anyway today I’ve got to get it out of the back of my Jeep and start the process of re-installing. Shop warned me to be sure to flush the lines really good as there was a lot of metal floating around inside transmission, especially in governor but no chunks laying in bottom of pan.

I have a 90# air compressor but was wondering what to use to flush it with, how much pressure to use and any right or wrong ways to go about the flushing.

bashcraft

You need to pump something through the lines and the cooler. Solvent would be best but clean ATF would probably work too. Then blow them out with air.

David Mc

A professional machine would be better but these cans are better than nothing.

TimAT

I'd use alcohol to start with. Flush them out until there is no sign of anything in the lines, then a big shot of ATF, then rinse with alcohol again. The first round of alcohol will get most everything, the ATF is a little thicker so it will pick up any remaining trash, then the final rinse will prove it. Bottom line is you don't want to take a chance on contaminating your freshly rebuilt trans/convertor. I'd also replace the rubber sections of the lines while it's apart. Use hose marked "TRANS COOLER" and double clamps.
Even an in-line filter won't hurt. Remember the cooler itself too.

Jcpstrat

Thanks for replies ... I'm checking kits out.

diehrd

I was the first guy who told ya pull it .. Now i will help ya one more time .. ( LOL ) DO NOT go back into rad cooler go buy a large external cooler and run it into and out of that bypassing the rads cooler

jimvette999

Get a couple of the tall cans of AC flush, it's an evaporative cleaner under pressure you can push through and flush and then dry out with compressed air. NAPA sells it. The actual radiator cooler is small and an external cooler is just tubing with no reservoir so two cans should do a good job on the lines and cooler....IMO.
Jim

http://www.tooltopia.com/fjc-2407.as...FZABaQodC68Akg

http://www.autoacsystems.com/_store/detail/AR4201.html

Jcpstrat

diehrd ... I've been look'in for pics of where an external cooler gets mounted but haven't found any in forum yet.

In the other post I mentioned I don't plan on keeping this car as I've got another project I want to finish and can't keep them both.

This '74 isn't a matching #'s car due to engine & tranny but I've been trying to not take it any further away from stock than it already is with this re-conditioning so I'm leaning to just working hard on getting lines until they really run clear but I hear what your saying. I know that would be better in long run for tranny life. On the other hand I've had this car for 32 years without a hint of a problem with tranny until now and I haven't abused it but I haven't baby'd it either ... just enjoyed it. Thanks for yours and others input ... I'm check'in it all out.

mikem350

Flush the lines using brake cleaner and compressed air. Easy to squirt it into the open lines with the straw. I would do this in both directions. Have done this many many times. It leaves no residue.

The AC flush is good too

diehrd

It mounts with a nylon snap system to the front of the rad or condenser and would take less or the same time it takes to flush out a cooler .. Easy .. and even if selling it is cheap to do.

Jcpstrat

Just an update to say I got the overhauled TH400 transmission installed & hooked up last Saturday and drove it about 30min ... then parked it until today and check it for leaks, drove it again today and then checked again for leaks. No leaks and everything seems to be working FINE ... tranny has same characteristics I've enjoyed for so many years.

I ended up flushing transmission lines with a product called Kooler Kleen. I checked many of the suggestions out and no one I talked to indicated they wouldn't be fine but got steered to the above mentioned due to it being based on mineral oil and recommended by OEM's. Flushed lines both ways several times until only clear liquid came out .. then turned can over and used the remaining compressed air to blow any remaining fluid out.

I captured everything that came out and then filtered it and dried out the filter and it was interesting. When I shined a light on it you could see sparkles, almost like tiny shards of glass but it was metal particles. Not a lot but they were there. Thanks for all the suggestions.