Engine braking, jumps out of gear....boiing!!

[copydat]

So, the 520 that I picked up has a 180b L18 in it not a L20b as first thought. No biggie as I am putting together my CA now anyway.

 

When driving the 520 and engine breaking into turns or roundabouts, I shift into 2nd gear and it keeps jumping out into neutral. It will stay if I keep my hand on it and hold it in there but with such a small steering wheel and 8inch fats up front can be hard to steer.

 

So is it due to a worn bush? selector bush? or worn teeth on 2nd gear? Gearboxes and all that bizo is something I've never bothered understanding. Others have had the same issue with other cars but no one can pin point what the issue might be. Need to know if it is a cheap easy fix or something more sinister.

 

Looking forward to hearing what you guys come back with.

 

 

Cheers.

[datzenmike]

I don't think that's fixable from the outside unfortunately. I've been told that's a synchro problem.but I think a really badly worn bearing will allow the main and counter shafts to move away from each other when stressed under load. Does the tranny whine?

[copydat]

no whine.

 

Didn't think it would be a simple fix. Bugger! I'm guessing it won't get any worse than this right? :unsure:

[datzenmike]

:lol: My 620 started jumping out of 5th... no worries I said, I can just use 4th and I don't drive out on the highway much anyway. Two weeks later it was jumping out of 2nd............ The bitch of that was needing both hands to turn the wheel when turning corners in town in the most used gear at that speed..... 2nd.

[H5WAGON]

My 4spd has been popping out of 1st.....and not so smooth shifting. I have to push/hold the shifted in 1st...or it bangs out if 1st.

 

Swapping out another 4spd today.

[copydat]

:lol: My 620 started jumping out of 5th... no worries I said, I can just use 4th and I don't drive out on the highway much anyway. Two weeks later it was jumping out of 2nd............ The bitch of that was needing both hands to turn the wheel when turning corners in town in the most used gear at that speed..... 2nd.

 

You are describing exactly what is happening with this 52o and its 2nd gear. I've had to alter my driving style/technique and simply shift to neutral as I roll up to lights etc. Cornering is completely different, almost all corners locally are 2nd gear corners and rolling around a corner in 3rd or neutral just ain't right. I gotta get my CA built and quick.

[datzenmike]

So this is the 520 4 speed???

 

 

Jumping out of second can be several things but we'll concern ourselves with only the ones that can actually be done with the tranny in the vehicle. One of them is a worn detent ball. The detent ball is spring loaded and is pushed hard against the 1st/2nd shift rod. The shift rod has two grooves in it and the detent ball simply rolls along the surface of the rod as the shift rod slides forward and back. The ball drops down into the groove at each gear and resists movement, in effect holding the attached shift fork in that gear. You will have noticed a slight effort needed to pull the shifter out of any gear? well that is the detent ball and spring. A worn ball or broken spring can cause it to not hold the fork in gear. (of course a worn ball/broken spring would likely affect 1st gear equally as much) Anyway it might be worth a try to pull the spring and detent ball out and inspect them. Maybe a slightly stronger spring will help.

 

I guess I held my camera sideways and you will have to figure out that the rear of the passenger side of the 4 speed is to the top and the front to the bottom. The bolt near my right finger is the 1st/2nd is the checking ball plug and is more on top than the other two which are on the side. Remove it and there is a checking ball spring, then a checking ball.... under that I'm not sure. You will need a slender magnet to remove the ball. perhaps the spring is broken and it's an easy fix. Watch out, the spring may jump out.

 

 

 

 

 

 

.

[copydat]

Thanks for the info! Love this site, such a good resource!

 

It is actually a 5 speed from a 180b. Is this explanation the same principle? If so, I'll have a good look at getting the spring and ball identified and replaced if necessary. Seems simple enough... (Famous last words!)

 

 

Thanks again Datzenmike!:cool:

[wayno]

My 1985 nissan 720 shortshaft 2WD 5 speed jumped out of 1st under compression for several years, and the 2nd gear syncro wasn't that great either, I checked the gear oil and it looked fine, so I let it be, as I rarely am under compression in first and could hold it there if I remembered, and I light touched it into second. I recently got around to changing that transmission out, as it started to make that front bearing noise after all these years, but I have not pulled it apart yet, is there anything I should specificly look for? When I pull it apart, I will take photos, but I need to purchace a bearing kit first. What tranny # is it Datzenmike? It's a 1985-86 shortshaft out of the regular cab shortbox nissan 720? I need to buy the kit with the bearings and syncros.

[datzenmike]

Nissan 180b... that was a 610 here. I've heard about the optional 5 speed but have little info on them. I assume it's a dogleg? with reverse above first? It would have a front and rear case with adapter plate sandwiched in the middle.

 

It would not have a removable oil pan on the bottom, (left) but a smooth case and a large nut pointing downward just forward and slightly right of the rear mount. (right)

 

If it is a dogleg 5 speed then the placement of the 2nd gear shift rod is different. On the dogleg I would be the pointing to the 2nd/3rd shift rod with my lower finger. The lowest bolt is 4th/5th gear shift rod.

 

 

 

For my own info do you know the length of the 180b 5 speed? Is it about 26" or closer to 31"? I have info suggesting that only the long doglegs were in Japan and Europe. I'm expecting 31.5" as this was the length of the 4 speed used here in N Am. Do you have a picture of it?

 

.

[datzenmike]

My 1985 nissan 720 shortshaft 2WD 5 speed jumped out of 1st under compression for several years, and the 2nd gear syncro wasn't that great either, I checked the gear oil and it looked fine, so I let it be, as I rarely am under compression in first and could hold it there if I remembered, and I light touched it into second. I recently got around to changing that transmission out, as it started to make that front bearing noise after all these years, but I have not pulled it apart yet, is there anything I should specificly look for? When I pull it apart, I will take photos, but I need to purchace a bearing kit first. What tranny # is it Datzenmike? It's a 1985-86 shortshaft out of the regular cab shortbox nissan 720? I need to buy the kit with the bearings and syncros.

 

It will be the FS5W71B and should have the larger 62mm counter bearing. Some parts companies list it as 60mm or something else but should be 62mm

 

 

Earlier ones are 56mm.

 

If you are changing all the bearings and synchros this should fix it.

.

[wayno]

It will be the FS5W71B and should have the larger 62mm counter bearing. Some parts companies list it as 60mm or something else but should be 62mm

 

 

Earlier ones are 56mm.

 

If you are changing all the bearings and synchros this should fix it.

.

 

Thankyou datzenmike, yes it does have the small bearing, so I am going to have to buy that bearing extra, unless the earlier longshaft kit with the smaller bearing will work on a shortshaft, will it? I have not had any of the L20b cases turned out to the bigger bearing yet, haven't totally lost the bearing in one of them yet, I always pull the tranny before that happens, as it may be a noisy truck with the SUs, header, and dually axle, I can still hear when something isn't right.

[datzenmike]

Do you know if that is the original tranny? I would think not if an '85 and having the smaller counter gear. The larger counter bearing was introduced for the '85 model year. If you are absolutely sure then order the kit by year and X your fingers.

 

Long or short trannys should have the same pieces in it.

[wayno]

Do you know if that is the original tranny? I would think not if an '85 and having the smaller counter gear. The larger counter bearing was introduced for the '85 model year. If you are absolutely sure then order the kit by year and X your fingers.

 

Long or short trannys should have the same pieces in it.

 

It was the original(first) shortshaft tranny that i built 5+ years ago for my work truck that has a L block in it

, the gear part of the tranny came out of a 85ish 720, the front case came out of a 80 datsun 720, the shortshaft had the big cluster gear bearing, till I changed it, so the L case would go on to it. So you beleave that the 85-86 syncros and all the bearings except for the lower front cluster gear bearing are the same as a 1982 longshaft 5 speed transmission? I ask because if I can buy the earlier kit, it will have that lower front small bearing I need instead of the big one.

[datzenmike]

So it's an '85 tranny with '80 counter bearing and case. Order the '85 kit and order a separate '80 56mm counter bearing... that should do it.