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Assessing a pick-a-part transmission


Lostcause521

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I pulled a 4speed tranny out of a early 620 this weekend and I need some tips on assessing if it's good. The input shaft splines are smooth and strait, the input shaft doesn't wiggle side to side, I can feel a change in resistance spinning the output shaft when I change gears so I am assuming it engages each gear and spins smoothly in each gear, and the output shaft splines are smooth and strait. It also turns the speedo cable. Is there anything else I can check from the outside and is there anything I can check by removing the pan and peaking inside? Thanks.

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Worry not, dissassembling a Tranny is easy and adds peace of mind (if you know what to look for).

All you need to reassemble is one bearing cover gasket and sealant.

 

I took my 5SPD apart because it sat in the rain for months, looked brand new inside. Just make sure when you put it together you don't get any grinds or noises, I had to take mine apart a couple times to realign everything.

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I pulled a 4speed tranny out of a early 620 this weekend and I need some tips on assessing if it's good.

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Early 4 speed is this...

7104spdremoval003Large.jpg

 

...so pull the bottom off and take a look. Best if never been drained so you can look at the oil. It should be changed about every 25K-30K miles so who ever does that? Maybe the original owner but after that the 4th or 5th don't know or car they just drive them. So if the oil come out clear and golden that's good. I think the drain bung may be magnetic on these... they are on the later 71B 4 speeds. Expect to see a black paste of metal filings but free of chunks and ball bearing parts. Wipe clean so that the next time it's removed it will show what has been added.

 

You can turn the input in all gears and feel the output turn to confirm that there is a connection when in gear. As stated the best evaluation is to drive it. Bearings and synchros may look ok but still growl or not shift properly. If installing, be sure to replace the output seal, they are less than $5. Put grease on the lips so it doesn't tear or start up dry.

 

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I'm sure it needs a new output shaft seal, there was a significant amount of grime at rear of the transmission on the vehicle. When I pull off the pan, will damage look as obvious as chipped gear teeth, or much more subtle than that? Also, what should I use to clean the inside of the pan and the bell housing, mineral spirits?

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It was at a Pick A Part, so yea they probably drained it before they put it in the yard. i want to degrease the rest of the tranny before I pull the pan off, I will look for signs of heat damage as well as general wear. 

 

 Oil at the front could be a bad engine rear seal too

The clutch and flywheel were clean as a whistle, but the dust boot around the clutch fork was gone, and the inside of the bell housing is fairly greasy. Most of the grime is around the pan and the rear of the tranny.

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