# Bought a Z31, now what?



## Darkstar (May 31, 2005)

Alright, so here's the breakdown. I bought an 86 300ZX for $1700 and 67,081 miles. I'm damn happy with the car but second gear's syncros are killing me. shifting into second gear usually requires a precise RPM shift to go in without that horrible noise. I was thinking of replacing the transmission for the following reasons:

1) high (4500-5000) RPM shift from first into second or third gives me a grind (3rd gear grind is very short but second gear grinds at almost every RPM above 2000)

2) shifting into second gear is hell like i said above, unless it's at about 3000 RPM it's not happy.

3) it's a 20 year old tranny.


should i get a NEW tranny or a slightly used one or just rebuild this one? obviously the first option is the most costly but is it worth it?


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## Zen31ZR (Mar 24, 2004)

Well, just for reference, my 85 turbo had double and then some your mileage, and no grinding. It was pretty notchy , though. 

You got pretty low miles for an 86, so unless that car was completely thrashed on it's entire life, something stupid is probably wrong. I would suspect the incorrect weight of gear oil was put in. Heavier oil will cause gear crashing, as the syncros slow down in heavier oil. The correct weight oil should eliminate that problem. I've read other places of even lighter oil being used in badly worn transmissions, all the way down to 10W40. I don't recommend that low a weight unless the transmission has been modified for it, though........

I'd also make sure your clutch system is making full pressure. If you don't want to do it yourself, have a shop bleed the clutch system for you.


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## Darkstar (May 31, 2005)

Zen31ZR said:


> Well, just for reference, my 85 turbo had double and then some your mileage, and no grinding. It was pretty notchy , though.
> 
> You got pretty low miles for an 86, so unless that car was completely thrashed on it's entire life, something stupid is probably wrong. I would suspect the incorrect weight of gear oil was put in. Heavier oil will cause gear crashing, as the syncros slow down in heavier oil. The correct weight oil should eliminate that problem. I've read other places of even lighter oil being used in badly worn transmissions, all the way down to 10W40. I don't recommend that low a weight unless the transmission has been modified for it, though........
> 
> I'd also make sure your clutch system is making full pressure. If you don't want to do it yourself, have a shop bleed the clutch system for you.


here's the thing, i bought it and i soon noticed the problem, i told my mechanic, he changed the oil in the transmission and then replaced the clutch as well since he was already in there. the problem persisted after a clutch and tranny oil change . from what i was told the mechanic suspects the previous owner held his hand on the shifter in second gear while driving causing the syncros to wear out faster. (mind you i'm a car noob)


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## Zen31ZR (Mar 24, 2004)

Darkstar said:


> here's the thing, i bought it and i soon noticed the problem, i told my mechanic, he changed the oil in the transmission and then replaced the clutch as well since he was already in there. the problem persisted after a clutch and tranny oil change . from what i was told the mechanic suspects the previous owner held his hand on the shifter in second gear while driving causing the syncros to wear out faster. (mind you i'm a car noob)


Old wives tale. If syncros wore out that easy, they wouldn't last the first year of the transmissions life....... Besides, that wouldn't wear the syncros, that would wear the shift forks. I've always had my hand on the shifter, even on cars I've owned for several years, never had any problems of that kind. 
Could just be a garbage tranny. Is this a turbo car? The FS5R90A is not the greatest, in fact it's the weakest of the Z31 trannys....


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## Darkstar (May 31, 2005)

nope, it's NA. insurance would kill me if i had TT or a v8. hence my "tame" v6


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## Zen31ZR (Mar 24, 2004)

Darkstar said:


> nope, it's NA. insurance would kill me if i had TT or a v8. hence my "tame" v6


86 also came in single turbo form. Cost me $60 a month to insure..... Only after '90 was there a TT model. Never was a v8 model, unless you built it yourself.


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## Darkstar (May 31, 2005)

ah, i thought the ZXT was TT. i know there wasn't a v8, just sharing my insurance company's hatred of young drivers. in short, no. it's natural aspiration.


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## Zen31ZR (Mar 24, 2004)

Darkstar said:


> ah, i thought the ZXT was TT. i know there wasn't a v8, just sharing my insurance company's hatred of young drivers. in short, no. it's natural aspiration.


Still not a bad car. Turbo is lots of fun, though. 
Interesting about your transmission. Cheap replacements abound for that car. 240SX tranny also fits, the 90 and up. It's the same transmission.


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## Darkstar (May 31, 2005)

Zen31ZR said:


> Still not a bad car. Turbo is lots of fun, though.
> Interesting about your transmission. Cheap replacements abound for that car. 240SX tranny also fits, the 90 and up. It's the same transmission.


that opens up new selections. what do you think i should do though, brand new, used, or rebuild? (mind you i don't know how to replace or rebuild so i'd have to factor in labor)


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## Zen31ZR (Mar 24, 2004)

Darkstar said:


> that opens up new selections. what do you think i should do though, brand new, used, or rebuild? (mind you i don't know how to replace or rebuild so i'd have to factor in labor)


New would probably be more than you paid for the car. Used or rebuilt would be the way to go, Maybe rebuilt since you don't know about junkyard trannys til they go in.......


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## Darkstar (May 31, 2005)

thanks for the advice. you probably saved me a large financial headache if i was to make this decision on my own.


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## Zen31ZR (Mar 24, 2004)

Most junkyards, at least around here, have a 30 day return policy, but I don't doubt they'd try to get out of it somehow. Rebuilt, at least you'd have something of a warranty (If you got yours rebuilt)


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## Darkstar (May 31, 2005)

Zen31ZR said:


> Most junkyards, at least around here, have a 30 day return policy, but I don't doubt they'd try to get out of it somehow. Rebuilt, at least you'd have something of a warranty (If you got yours rebuilt)


i found a used tranny at a junkyard online with a 180 day return policy. only problem i find with a return policy on a trany is labor. i have to pay to put it on and chances are i have to pay to take it back off if it doesn't work.


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