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Bought a 85 300zx base model with 96k miles. Ran decently for 2 months until the tranny blew. When I drained her I saw multiple teeth, a washer, a screw and shavings galore. I couldnt find any worthwhile transmissions to purchase so I decided to cut out the middleman and attempt to rebuild it myself. I'm only 19 and have been working on cars for less than a year so I can definetly learn it but I need some guidance as to where I should look for learning material and if there is anything in particular I should know before I start dissembling. My tranny is already out and I split it from the bell housing and where the stick shift is. Thanks in advance.

Also a bearing got completely destroyed near the idle gear and my clutch also got destroyed

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Start here

https://www.classiczcars.com/files/category/15-300zx/

There are a few options for a FSM download. They are easier to use on a computer as opposed to a phone. There should be full tear down and rebuild instructions in there.

If you shift too aggressively and flog these transmission they won't last. My2cents

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People have rebuilt severely damaged transmissions like yours and had good results but often when there is that much metal flying around there is a lot of extra damage.  Beyond the damage a typical rebuild will fix.  One damaged gear replacement could cost as much as having a used transmission shipped.

Take some better closeups and post them.  We like to look at damage.

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transmissions in your area appear to be $300-400 from salvage yards

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 Personally, I'd rather REFRESH a $300 - $400 trans from the wrecking yard than REBUILD a totaled one. Depending on the damage in the bad one (which is considerable) it may be cheaper and easier to refresh a different one. When you tear the old one down keep everything in order, (I've used wood dowels to keep all the parts in order and correct orientation) clean and inspect one part at a time. Lots of pics. Most of us are already trying to figure out what part of the trans went first and took out the rest. BTW, How much oil was in the trans when you drained it?

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45 minutes ago, Patcon said:

transmissions in your area appear to be $300-400 from salvage yards

Holy moly.  I found a Pick n Pull in Rhode Island.  Might be worth a look.  Pick n Pull salvages what they can before melting the cars down.  They're owned by a steel company, the salvage parts are gravy to them.  They make their money on the steel.

Of course, the whole northeast and all of its states is about as big as Oregon so there are many options.  Good luck.

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14 hours ago, Zed Head said:

Holy moly.  I found a Pick n Pull in Rhode Island.  Might be worth a look.  Pick n Pull salvages what they can before melting the cars down.  They're owned by a steel company, the salvage parts are gravy to them.  They make their money on the steel.

Of course, the whole northeast and all of its states is about as big as Oregon so there are many options.  Good luck.

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That would be a good find if you could get it out

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Here is some more pictures for you guys. The first two show the position of the blown bearing and I tried to get as close of a picture as a can. But the third picture shows some grooves on the gears and I wasnt sure if they are supposed to be there or not. Thank you all for the help I'm looking into cheap used transmissions now to rebuild but if my transmission looks salvageable let me know

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That bearing is bringing the output shaft too low to connect with the input shafts gears so correct me if I'm wrong but maybe if I replaced all my bearings and synchros it might do the trick? I don't see any missing teeth just some grooving on the gears

 

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15 hours ago, Mark Maras said:

 Personally, I'd rather REFRESH a $300 - $400 trans from the wrecking yard than REBUILD a totaled one. Depending on the damage in the bad one (which is considerable) it may be cheaper and easier to refresh a different one. When you tear the old one down keep everything in order, (I've used wood dowels to keep all the parts in order and correct orientation) clean and inspect one part at a time. Lots of pics. Most of us are already trying to figure out what part of the trans went first and took out the rest. BTW, How much oil was in the trans when you drained it?

There was about 6 or 8 quarts of oil that came out I'm not exactly sure but it was in that ballpark

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get a hand held impact driver (the kind you strike with a hammer) to release those torx screws. Also make sure you know which direction to turn the output shaft nut to loosen. Pretty sure its a CW to loosen, CCW to tighten (reverse of normal).

this guy has some good videos

 

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19 hours ago, Odinspeenbone said:

 When I drained her I saw multiple teeth, a washer, a screw and shavings galore.

Not uncommon for an adapter plate (center plate) bearing to fall apart.  Do you have pictures of the parts that came out?  Those are clues about where the damage is.

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Hi Odinspeenbone

Welcome to the forum. As you probably already noticed, plenty of willing members to offer advice where needed.

Looking at your photos, I would rebuild it. You mentioned in your first post, you found a tooth or a piece of one. Most probably from the reverse gear. The reverse gear can look very ragged, and still function well. Can you post a photo of the piece and maybe locate where it came from?

Points to check before going forward with rebuild.

- Look for cracks in the gears. A small chip will be ok, but cracks and signs of shattered teeth are a red flag.

- Syncho rings. Was the gearbox changing gears without grinding befoe the bearing fell apart? If not measure the rings against the specs, see manual for guidance. The external teeth look OK on the photos, but that is not what makes a good synchro ring. The small grooves on the inside are important and the wear is determined by measuring the distance between the synchro cone and the gear.

Note: Be carefull running your fingers around the inside. The small grooves can be razor sharp, especially on new rings.

If the synchros are within spec, you only need a bearing kit and seals.

- Once it's all dismantled, check the shafts are straight and within tolerance. Bent shafts can caused the transmission to jump out of gear. Didn't do it with worn bearing because the worn bearings had enough play to compensate.

- Use a good quality GL-4 transmission oil suitable for brass synchro rings. Redline MT-90 or the GM transmission oil are commonly refered too. The GM part numbers are AC DELCO USA p/n: 88900399. GM USA p/n is: 12377916.

I can post the part numbers for all the seals if you want to order then individually. Best would be to order a bearing kit and the rest of the seals, o-rings separately.

A kit like this would be what you would want for the bearings. They also sell bearing kits with synchros, but I have had poor performance from the aftermarket rings and endd up sourcing the rings from Nissan.

DTS-BK133

$129.89

http://www.drivetrain.com/parts_catalog/manual_transmission_overhaul_kits/nissan_f5w71_overhaul_kit.html

 

 

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Rebuild kit came in the mail today I'm going to get my workspace clean and ready for tomorrow and I'll let you all know how it goes. Thanks for all the help couldnt have done it without everyone who commented.

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If you have any questions. Feel free to ask.

Most of the parts in my list were for my 71B, but will fit the 71C. Main difference is the selector control section and the front cluster shaft bearing.

The bearing kit will have all the main bearings, front gasket and rear oil seal. Optional are the synchro rings (Baulk rings).

I ordered all the parts through Nissan with the exception of the Omega rear extension bush.

You may not need these parts, but I would reccomend replacing all the seals and o-rings. Most of them are not included in the bearing revision kit.

See photos for the bearings, synchros and rear extension bush.

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