sorry no info to help with you 1-2 shift problem.
just wanted to say i read your whole thread and its been very helpful.
im going to be rebuilding a th400 after the 1st of the year and your thread saved me from buying from that company (though they did try to help you out but i dont like waiting on parts personally)
its also given me a lot of info on what i need to do and look out for so thank you for that.
I'm glad you found the thread useful. I would not hesitate to use TPUSA again, however I feel that this kit is a better deal as it includes a lot more parts for roughly the same price:
https://www.ebay.com/itm/THM400-400-TH400-High-Energy-Alto-Deluxe-Transmission-Rebuild-Kit-Level-2/171339034831?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649
Also, I used the ATSG rebuild manual for my rebuild, supplemented by the B&M rebuild manual (for some of the more "at home" operations where you do not have the "correct" tools) and an extra page or two I found online. All three manuals were readily available in PDF form with a simple Google, here are links:
ATSG TH400 Rebuild Manual PDF:
http://shop.ukrtrans.biz/wp-content/uploads/catalogs/TH400.pdf
B&M Transkit Rebuild Manual (use only for reference. It is highly recommended you DO NOT use the modifications found in this manual. Only use it for additional reference)
http://files.dpbrands.com/bm/instructions/20229.pdf
Attached to this post are two additional PDF files. The first is a simple exploded diagram, the second is a recommended rear band/reverse servo inspection and setup write-up I found. The ATSG manual does not go into any detail on this subject so I found it helpful.
Additional Notes:
- Watch for the "fretting ring" or "case saver ring" behind the center support. It is important that you use one of these if it is present. The ATSG manual does not reference it during tear-down, but does explain it during rebuild.
- Inspect your plastic "silencer ring" for damage. It goes between gear sets. Mine was all chewed up, so I had to get a new one. $10 on ebay. I have an extra if anyone needs it too.
- ABSOLUTELY use a Transgo TH400 1&2 shift improver kit. Summit had the best price I could find on it. I used all parts except the manual-low override valves. The spring/hole size I used is in a previous post. This setup resulted in a not-too-firm shift that I like a lot. Summit had the best price by far: https://www.summitracing.com/parts/TRG-400-1-2
- Take extra care to measure and inspect your governor and it's bore. This is something I did not do and am now paying the price for.
- Folks seem to complain about getting the center support bolt out (the one behind the valvebody in the case). A 1/4 drive 12-point socket fits very nicely and makes removal and installation simple.
- Be sure to blow/clean out the existing cooler lines and in-radiator cooler. I added the Hayden after the existing cooler so that I am using both.
- Definitely get a new torque converter. Stock replacements are cheap on RockAuto.
If you have never rebuilt an auto trans before, the TH400 is a good one to start with. It's really a pretty simple trans. Just take your time, lay out your parts on a table in the order of removal, and stay organized. DO NOT RUSH. The extra time I had due to parts problems allowed me to really study the manuals and do lots of online research about what needs to be done and when. READ READ READ. You should know the manuals front to back before you get started. Always read ahead to make sure you know whats coming.
STAY CLEAN. I bagged all assemblies after they were completed in clean,new garbage bags.
I used two Home Depot 5 gallon buckets with a gallon of low-odor mineral spirits in each for cleaning and rinsing. Clean in the first, rinse in the second.
I chose to soak the bands and the clutch frictions in tranny fluid over night before installation. Some say this is not necessary, but I figured why not? Its free and I had lots of time.
I only needed assembly lube once to hold the thrust washer to the back of the direct drum during installation. I just used vaseline (from the babies. It smelled like flowers lol). I would not waste your money on actual assembly lube, I never needed it. Tranny fluid had enough "stick" to keep everything else in place.
I used Walmart Dex/Merc tranny fluid. At $11 per gallon the price was right. It's made by Pennzoil so it should be good stuff.
Anyway, long post. Hope its helpful for anybody looking to take on this project.
Oh. A couple of handy vidjayos I found on the you-tubs:
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