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280zx 5 Speed Won't Reverse


Muzez

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To loosen the fill plug, I suggest heat with a 3/4 drive to 1/2 reducer (https://www.amazon.com/TEKTON-47823-4-Inch-2-Inch-Reducer/dp/B000NQ4R4G) and 1/2 drive 1/2 pipe plug socket (https://www.amazon.com/gp/product/B006L23ILO). That way you can use an impact gun or breaker bar safely on the fill plug. By the way, using the socket and reducer combo only works if the transmission is out of the car. There isn't enough clearance in the tunnel to do this with the transmission in the car.

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On 11/29/2020 at 5:12 PM, SteveJ said:

To loosen the fill plug, I suggest heat with a 3/4 drive to 1/2 reducer (https://www.amazon.com/TEKTON-47823-4-Inch-2-Inch-Reducer/dp/B000NQ4R4G) and 1/2 drive 1/2 pipe plug socket (https://www.amazon.com/gp/product/B006L23ILO). That way you can use an impact gun or breaker bar safely on the fill plug. By the way, using the socket and reducer combo only works if the transmission is out of the car. There isn't enough clearance in the tunnel to do this with the transmission in the car.

@SteveJ I cleaned up the plugs today and am letting the penetrant do its magic. The tooling is on order, but I was measuring the plug today. For the 3/4 drive to 1/2 reducer, it feels like there will be a little air gap between the plug and the socket. Is the goal to heat the plug itself? Or the fitting that the plug sits in? 

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I'm not sure what you mean by air gap. After the penetrant has had time to work (and I hope you are using something strong like Kroil), apply heat on the fill plug. The 3/4 to 1/2 adapter should fit on the plug. Then you can use the 1/2 pipe plug to fit a 1/2 drive breaker bar or impact. 

When I tried it before, the 3/4 adapter seemed to fit the fill plug well. If yours was abused, your mileage may vary. 

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Quick Update: Still working to get the fill and drain plugs unstuck. Been dosing them with PB Blaster and heat for about a week, but no luck yet. Was thinking of maybe backfilling the warped parts of the drain plug with JB cold weld to form it back into more/less a square. Will keep you posted. 

In the meantime, I have been stripping away some of the red paint from the trans. Luckily, they didn’t do a great job of degreasing before they applied the paint, so it’s coming off pretty easily. Should have that gone today or tomorrow. 

One question for you guys: Some parts of the Trans case are smooth, but some areas have a texture to them that resembles slightly wrinkly produce. I am assuming the texture is part of the casting and is just more apparent from due to the dirt. Is this something you guys have seen before? And anything to worry about?

Most of the areas that have it look like this:

C708DD6E-E70C-4F54-9475-0FA4E458C24C.jpeg

This was probably the worst of the sections

6891CCB3-F4D2-44DE-A9C7-245A71D5E5E1.jpeg

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15 minutes ago, Muzez said:

One question for you guys: Some parts of the Trans case are smooth, but some areas have a texture to them that resembles slightly wrinkly produce. I am assuming the texture is part of the casting and is just more apparent from due to the dirt. Is this something you guys have seen before? And anything to worry about?

Nothing to worry about, they all look like that.  If the trans is separated from the engine the best way is to haul it outside on a warm day and scrub down multiple times with a strong degreaser and a garden hose. I'm not sure JB Weld will stand up to that kind of pressure without cracking.  On sloppy fitting drain and fill plugs you can use pop can aluminum as shim stock,  cut 1/2" strips off of a pop or beer can and wrap it around square end of your breaker bar, 2-3 winds should do it then tap the 1/2" drive into the drain plug.

MAP gas in the yellow bottle burns hotter than Propane (blue bottle).

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1 hour ago, SteveJ said:

Try Kroil instead of PB Blaster.

Just ordered. Will be here in 2 days! What is so different about this stuff?

1 hour ago, grannyknot said:

Nothing to worry about, they all look like that.  If the trans is separated from the engine the best way is to haul it outside on a warm day and scrub down multiple times with a strong degreaser and a garden hose. I'm not sure JB Weld will stand up to that kind of pressure without cracking.  On sloppy fitting drain and fill plugs you can use pop can aluminum as shim stock,  cut 1/2" strips off of a pop or beer can and wrap it around square end of your breaker bar, 2-3 winds should do it then tap the 1/2" drive into the drain plug.

MAP gas in the yellow bottle burns hotter than Propane (blue bottle).

Good deal re: exterior texture. Unfortunately, it is officially winter here in Chicago and there won’t be a warm day for 3-4 months haha. I tried washing my weathertech liners after I brought the trans back and my pant leg froze.

Re Aluminum: I like this idea way better. Will give it a try! If all of this doesn’t work, it might be time to get professional help haha.

I have a can of MAP, but have been holding off on using it on the fill plug thus far because there is a sensor 2” away and was nervous about the extra heat melting it. 

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24 minutes ago, Muzez said:

Just ordered. Will be here in 2 days! What is so different about this stuff?

I have a can of MAP, but have been holding off on using it on the fill plug thus far because there is a sensor 2” away and was nervous about the extra heat melting it. 
 

Kroil really works well !

As for the sensor, it is threaded in just like the plugs you can't get out. Catch 22 😀

Really, the sensor will come out, just apply the Kroil on the threads of it also.

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I used PB Blaster on a plug for an O2 sensor bung. The plug wouldn't budge. I tried the Kroil, and I got the plug loose and removed with no thread damage.

I should also add that if you look up penetrating oil comparisons, Kroil is usually at the top. https://www.google.com/search?sxsrf=ALeKk03g9LCNLRF-NgNXl6cC20RsdNj0ew%3A1607365501682&ei=fXPOX5qVKcugtQX-gZXYCQ&q=penetrating+oil+comparison&oq=penetrating+oil+comparison&gs_lcp=CgZwc3ktYWIQAzICCAAyBAgAEB4yBggAEAUQHjoECAAQRzoGCAAQBxAeOggIABAHEAUQHjoICAAQCBANEB5Qu-0JWMvxCWCr9gloAHADeACAAXWIAbQDkgEDMS4zmAEAoAEBqgEHZ3dzLXdpesgBCMABAQ&sclient=psy-ab&ved=0ahUKEwjax4GOv7ztAhVLUK0KHf5ABZsQ4dUDCA0&uact=5

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3 hours ago, crayZlair said:

As for the sensor, it is threaded in just like the plugs you can't get out. Catch 22 😀

 

Pretty sure the switch (not a sensor) is a straight thread, not a tapered pipe thread like the plugs, and it has proper flats for a wrench.  17 or 19 mm if I recall right.  Should come right out, your biggest worry will be damaging the wires which will be rock hard after 40 years of baking. 

Heat will have a big effect.  Those plugs have been bathed in transmission fluid on the other side for years and are steel in aluminum.  If they've never been out then they still have Nissan's super sealant on the threads.  Heat will loosen the sealant.  Heat.  Heat. Heat.  When I was removing my diff fill plug I could only get it to turn after heat.  As it cooled down it tightened up again.

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Putting it into 1st and then into reverse is my way to limit any grinding. There those three bolts in the sandwich plate between the bellhousing and the main/tail section. There is a spring and ball bearing that is use as an indent. Too much pressure and the shifter is locked in place. Too loose and it will come pop right  of gear without much effort. Those springs in most trannies have never been replaced.

I'm not saying this is the cause of your issues but it's one more thing to consider. I solved my problem by getting a longer bolt and a few washers. A little trial and error got the issue fixed that is until it grenaded several race days later caused by me not any of the repairs. Rebuilt  and back in in a week.

Edited by gnosez
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  • 4 weeks later...

Quick update for this topic! Sent the trans out to a Z specialist in the Carolinas for inspection and rebuild. Main bearing was shot, but otherwise everything else was in ideal condition. Posting some before /after pictures for our mutual gratification.

Before:

57883E14-0EAB-447A-B161-289AE459A16E.jpeg

197CA16E-1929-4A81-B6FF-131F31FA4282.jpeg5D66E7D9-5DC6-460D-A579-9BF6DABDAF89.jpegMissing a few: C6B61A87-5AD4-44DF-80B3-0774F537D150.jpeg
After:

900F2BA8-36FB-4E92-9194-6634BEFF191D.jpeg

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On 1/2/2021 at 11:13 AM, Patcon said:

Who did you send it to and where exactly?

The shop is in North Carolina. Came highly recommended by a friend in the Z community up here in Chicago who was driving down to do rebuilds on a few transmissions for his 240z and 510. I believe the owner of the shop is a retired race Z builder. I can ask my friend who made the connection if the shop is taking more work, or if this was a personal favor. 

You looking for a rebuild @Patcon

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35 minutes ago, Muzez said:

The shop is in North Carolina. Came highly recommended by a friend in the Z community up here in Chicago who was driving down to do rebuilds on a few transmissions for his 240z and 510. I believe the owner of the shop is a retired race Z builder. I can ask my friend who made the connection if the shop is taking more work, or if this was a personal favor. 

You looking for a rebuild @Patcon

I think it is always a good idea to post up resources for the community. That way we can support those vendors that help keep these cars on the road.

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  • 10 months later...

@Muzez I just picked up a 280ZX and has the exact same problem, unable to shift into reverse. 1 - 5 feel fine. Was there anything specific that allowed you to get to reverse? Did you fiddle with the lockout mechanism? Or when you removed the gearbox did it just come good somehow?

 

Thanks!

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On 12/3/2021 at 3:55 PM, Tristan said:

@Muzez I just picked up a 280ZX and has the exact same problem, unable to shift into reverse. 1 - 5 feel fine. Was there anything specific that allowed you to get to reverse? Did you fiddle with the lockout mechanism? Or when you removed the gearbox did it just come good somehow?

@Tristan In my case, my first problem was not knowing that there even was a lockout because it doesn't exist on the early 5-speed. So first thing to check is that you can't go from 1 to R. The second issue was that all shifting was a little crunchy because my main bearing was destroyed so some metal fragments were preventing the change. 

Zed is right about checking the shifter and shifter bushings in case it is sticking on something since its probably the fastest check. 

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7 hours ago, Muzez said:

@Tristan In my case, my first problem was not knowing that there even was a lockout because it doesn't exist on the early 5-speed. So first thing to check is that you can't go from 1 to R.

I think you mean 5th to Reverse. The reverse lockout was developed to stop people hitting reverse when coming back from 5th to 4th gear. That is one of the reasons reverse gears are zo badly chipped in the ealy model 5 speed.

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6 hours ago, EuroDat said:

I think you mean 5th to Reverse. The reverse lockout was developed to stop people hitting reverse when coming back from 5th to 4th gear. That is one of the reasons reverse gears are zo badly chipped in the ealy model 5 speed.

Thanks for clarifying the lockout behavior @EuroDat! Though I was recommending to try shifting from 1st to Reverse.

I wasn't sure if he knew the lockout is only from 5th to Reverse, so the first diagnostic step Tristian can do is to see if he can shift from 1st to Reverse (or any other gear than 5th) to make sure its not just the lockout blocking him from shifting. 

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The shop is in North Carolina. Came highly recommended by a friend in the Z community up here in Chicago who was driving down to do rebuilds on a few transmissions for his 240z and 510. I believe the owner of the shop is a retired race Z builder. I can ask my friend who made the connection if the shop is taking more work, or if this was a personal favor. 
You looking for a rebuild [mention=22019]Patcon[/mention]? 

Where in NC is this shop? I have a spare 5 speed. Wondering if the place is near me. This spare 5 speed needs a rebuild, otherwise what would I do with it?


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3 hours ago, Zed Head said:

Actually, it would be from neutral to reverse.  Straight right, then down.  To get past the lockout mechanism.  Just saying...

Can you tell I haven’t installed the trans yet? 😛 Thanks Zed.

@Av8ferg the guy I used is retired, but takes on work from time to time. I just messaged him to see if he is taking on new work. If you want to PM me with your contact details, I will forward them on. 

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I am relatively confident the box I have does include the reverse lockout. I have the workshop manual, and the ones with the lockout have a diamond-shaped plate on the passenger side with two 10mm bolts. I have only looked through the shifter hole, and I think I can see that plate/bolts. The car is a 1979 model though.

I cannot shift into reverse from any starting position (tried neutral, 1st, 2nd, 5th).

I'll check the shift bushings next, like you said, very easy to get to. If that yields no result, then I'll try get to the reverse lockout plate, undo the bolts, slide out the mechanism and check for issues. The only tricky part is getting to those bolts without removing the box as they are almost directly above the transmission mount.

Note: I am yet to drain/replace oil in the box.

I appreciate all the help and info 🙇‍♂️

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