Hey Guys!

 

New to the forum, would just like to say hello but also ask for a bit of help regarding auto transmission. Sorry about the long post - here is the back story but if you just want to know the problem then please just skip to the bottom.

 

My dad bought a 1992 Red 300ZX TT 2+2 4spd Automatic about a year ago for £1000. It had a seized engine so we trailered it back and have since been working on it in and out of other commitments.

 

After removing the engine and dismantling it the problem turned out to be a big end cap, it had come lose and detached - jamming the engine solid. This matches the description by the previous owner as they said they were going along the motorway and suddenly it stopped (luckily an automatic). How they didnt hear it beforehand I have no idea but we got the crank reconditioned, got a new conrod and cap and put the engine back together. Luckily damage to the crank case was very minimal, the only damage being a few reasonable scratches and a bore spray nozzle bent a bit although nothing out of place.

 

After fiddling with all the pipes and electronics for a few days (they werent set out in order anymore as we'd moved house since removing the engine) we had the engine in and running. It started running a bit miserable but eventually after some tweaking it seems to run nice and sweet - there is a small rattle with one of the auxiliaries which we are investigating.

 

Took it in for MOT yesterday, just 3 new tyres to pass. They also said it wont change into top gear, the car hasnt been driven hardly anything (maybe 2 miles) in the last year or more, any idea what it could be?

 

Again sorry for the long post.

 

Thanks.

mits be silly but is overdrive switched on?

Welcome matey :)

mits be silly but is overdrive switched on?

 

Not got a clue its still at the MOT station at the moment but its very possible. It was a mechanic that took it for the drive though. I'll certainly mention it.

 

What exactly are all those buttons near the gear lever?? Power... O/D etc.... I have not got a clue what they do. Overdrive I thought was like a 5th gear as 5th in a manual is usually overdrive compared to engine revs??

 

Thanks Guys

Red

Not got a clue its still at the MOT station at the moment but its very possible. It was a mechanic that took it for the drive though. I'll certainly mention it.

 

What exactly are all those buttons near the gear lever?? Power... O/D etc.... I have not got a clue what they do. Overdrive I thought was like a 5th gear as 5th in a manual is usually overdrive compared to engine revs??

 

Thanks Guys

Red

 

The autobox is a 4 speed box, so 3 gears plus overdrive. The auto wont go into the final gear until up to temperature or over 45mph.

 

The powers switch holds the gear longer so will rev higher before change, the hold button is for wet weather and pulls away in second gear. If you floor the accelerator the power light comes on automatically without using the switch.

 

The OD button is like the 4th gear, off around town and on the twisties for better response and on for cruising

 

Occasionally the oil strainer in the box can get clogged causing gear change/running problems or weak solenoid pressure in the box, so as part of a service schedule its recommended to drain the gearbox oil, take of the sump and clean out the strainer/filter of any debris or gooey fluid.

 

You wont be able to drain all the fluid as the torque convertor tends to hold a few litres on its own, so worth doing another box oil change after a few hundred miles to help the old stuff flush out.

 

HTH

Edited July 23, 201114 yr by groover

Thanks groover. I just checked and O/D has been tried on and off and its not that so it may be that it wasnt tested fast enough or warm enough. I recall it going into the final gear when we took it for a drive, so it was weird being told it wouldnt. I'll mention about the oil strainer but I assume its fine as the box was replaced a year ish ago.

If they drove around town then i doubt it would have been going fast enough and i find with mine, once up to temp it will go into final gear at lower speeds, oil is then thinner with the heat.

It has now been taken for a good 5 mile drive a few times and it still wont change up, its fine for 1st and 2nd but 3rd just wont go.

 

The box had been recently changed but one thing odd that we noticed which iv just remembered is that when we took the engine out when the torque converter was taken off no fluid came out of the shaft.....

 

I'm puzzled lol.

Do an auto box diagnostic, follow this and it will flash up the codes http://www.300zx.co.uk/forums/showthread.php?t=128846

hello and welcome, can do a conzult auto box test on it if your near St.Ives see what it says but if you have flushed it and replaced it with new fluid and its the same i would guess the box is at fault!

 

dan.

It seems it has a mind of its own now, we were driving it through a local town and decided to use the shifter to change it into second and it dropped a gear.... not so much worried about the gearbox now though (however ill check out that link, thanks!).

 

Main thing now is a tap which has emerged after fuelling the car up and taking it for a decent run. The fuel was normal unleaded from a Texaco garage and we have never had trouble from their fuel before including in our old 280zx.

 

I have got a video with the tapping noise on it id be very grateful if you could have a listen and see if you have any ideas. We've though maybe cam follower or injector but it is quite loud and hasnt been there all the time (that we've noticed).

 

Thanks.

 

Video:

http://imageshack.us/clip/my-videos/839/shq.mp4/

personally i always use premium fuel, dont know if yours is a uk or not, if that noise was on any other car id be saying it sounds nasty, but with the zed it could be somethig silly, sure some1 will advise better

The bottom end has been dismantled etc and the head has been taken off (only on one side). I cant see it being anything serious like that though. :/

 

Its really hard to locate the source of the noise, it sounds louder beneath and at the back but then also sounds louder on the passanger side.

 

Thanks.

UPDATE:

 

We took the sump off in-situ and have removed the big end caps and got the shells out (they're new oversize ones since we had the crank skimmed). Alot of them have copper showing underneath like they've been excessively rubbing, even though the cars only done about 15 miles since replacement, is this normal? The big end caps were all still tight on.

 

Could the tapping and shell wear possibly be due to the oil? Kevin Coopers sold us some 5w 30 Comma Fully Synthetic oil saying thats what they recommend for that engine. What oil do you guys use?

 

I'm off to order a new full set of oversize shells tomorrow. Unlike my father I'm a bit sceptical though and think this may be a waste of money.

Could be a number of things,crank grind may not be done to a high standard,bearings may be wrong ? if all the bearings are on the copper its one of the aforementioned.Did you clean out the engine oil cooler ? how much did the machine shop remove ? what undersize bearing did you get ?

The crank grind was fine the place used has a good rep. Plus the oversize shells were provided from the same place with the skimmed crank. What about too thin an oil? 5w 30 is too thin for this engine surely?

 

Cheers

That wouldnt cause the issue you had,id still say its a crank bearing relationship issue.if it was contamination id expect for maybe a couple of bearings to have worn but for all of them summit is seriously wrong.I wouldnt put a set of bearings in until you establish exactly what went wrong or youll just waste your money.

It was 3/4 shells that were worn (didnt take that many off just yet). Dads changing them all anyway he's convinced thats whats wrong ill update when we know.

I would check the oil pupm too make sure there is enough oil pressure go to the bearings.

Oil pump has been fully tested. The damage seems to have been dirt in the oil on further inspection. Going to fit new shells and completely clean out the oil cooler again. Could dirt between the crank and shells cause that tapping noise?

First of all sorry to write the same thing twice in two different topic.( I just went blank :) ) Regarding the tapping noise if it's coming from the bottom than yes, but usually tapping is coming from (one or more) the hydraulic valve lifter(s) in the head as crank bearing issues more likely to make knocking noise at certain revs.

Well the tap did get slightly deeper at say 2500 rpm. Im picking up new bearings tomorrow will update asap when engine is running again.

 

Thanks for your help.

Hello Guys, it's been a while, everything is running greatly now engine wise however the Auto Trans still wont change into top, it revs the crap out of itself and would continue to do so until it runs out of fuel, not driving it at the moment as its a recent engine rebuild so its just going to kill itself.

 

Any ideas? Its a Jap model with Hold and O/D.

 

Thanks

Josh

Faulty speed sensor maybe