TH400 Problem - Sat to Long

[happyhoppy]

Installed what was a good Chev TH400/Jeep tailshaft with a low range quadratrac but it had been sitting for about 12 years. It did work well for a short time and as it heated up it would barely move. I changed the fluid and filter three times now and it does get better each time but I can't keep doing this, I may be destroying something else. Filter does clog up. Is there a way to flush this to solve my problems or is there something else?
I know this was a good tranny because we use to wheel in it back in 1993 just before it was put into storage.

[Lifted79CJ7]

Not that I am much help, but do you have a temp guage? It helped tremendously on watching what my tranny was doing vs performance. Sounds like it needs a THUROUGH cleaning!! Not sure how to flush an auto besides a big ol bucket and take the line from the tranny to the cooler and those both to the big bucket. I used a tranny temp/external filter kit that I bought from www.summitracing.com , part number PRM-10677 . Hope this helps a little!!
Jack

[happyhoppy]

Thanks for the info - didn't realize there was such a unit. Are the replacement filters an off the shelf item? Going to try flushing after I get the unit. Did test with pressure gage and it would reach 115 psi like it should have but it didn't last. Temperature gage will tell me more.

[Lifted79CJ7]

Yeah, pretty cool, wish I had never sold it (was parting out my jeep at one point to move to va beach and was sick of sinking money into something that didn't run). At some point I will buy another one. It just uses off the shelf oil filters (engine oil), so oil changing is soooo much easier, plus adds lots more fluid adding a little extra cooling efficiency. I say it is a must buy for any auto user. Only complaint was that it didn't match my other guages.
Jack