Question for haymaker about 4020 power shift transmissio

I read a post where you rebuilt the trans on your 4020, I have a 4000 we are going to do and looking for and advise I can get please, thanks again.

This may be obvious but do not attempt it without a manual, see link. You will also want to perform the required pressure tests before tear down so you are sure what is repaired addresses the issues you were having.
JD publications

(quoted from post at 15:13:19 03/19/23) This may be obvious but do not attempt it without a manual, see link. You will also want to perform the required pressure tests before tear down so you are sure what is repaired addresses the issues you were having.
JD publications

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^^^^^^^^^^This^^^^^^^^^

Proper diagnosis before turning wrenches.

(quoted from post at 14:13:19 03/19/23) This may be obvious but do not attempt it without a manual, see link. You will also want to perform the required pressure tests before tear down so you are sure what is repaired addresses the issues you were having.
JD publications

Click to expand...

Agree 100%. I've worked with a couple people who would rather tear stuff apart first and THEN figure out what's going on inside a transmission. You're far better off going through step by step tests FIRST even if there's an obvious issue. There's multiple reasons for this: 1. You might not know there's more than one problem going on. 2. You might not actually physically see the problem when you get inside. 3 When working with old stuff you're going to find questionable parts inside that you won't know if they're safe to reuse or not. Example would be worn sealing ring surface inside a drum that can cause excessive leakage. If an element leak check is performed before disassembly you can rule out whether or not these sealing ring surfaces are causing any issue. Finding parts for these old transmissions is hard so there might be some things you'll have to reuse even though they're not in ideal condition.

I know someone that said he had a leaking element inside transmission. When he took it apart the crack in the drum couldn't be seen with the naked eye but he knew there was a problem with it because he performed an element leak check before disassembly.

I know another guy who had to tear a new gen power shift (30 or 4020?) apart twice because he assumed there was only one problem with it and didn't run any tests before disassembly the first time.