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andynogo

M35 Gearbox or attesa issues?

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I have a few issues with my car at the moment:

Pretty bad shuddering in reverse with wheels turned (fine when reversing in a straight line)

Shuddering when driving in a straight line- almost feels like the car is rhythmically binding up a bit. Worse with power on, but still happens when rolling in neutral.

Really really bad shudder on moderate and hard acceleration. Goes alright but it's quite nasty- almost verging on quite a harsh vibration/shudder/clicking noise/feeling. At first I thought it was a terrible misfire/boost cut but I'm fairly sure it's a mechanical drivetrain issue.

The engine is running well so it's not misfiring. All new coils, O2 sensor, MAF, exhaust, CV's all checked and good (one replaced). Wheel bearings all good. New gearbox fluid, need to flush attesa fluid and transfer case. I've got 370Z staggered rims but was doing this with the standard ARX rims as well.

The attesa pump appears to be working properly, no 4wd light on dash.

With an upgraded ecu with tweaked shifts it was doing some really nasty gearchange bangs (particularly on downshift at 100k's and some gearchanges at low speed), alleviated by Christian kindly sending me a re-programmed ecu without gearshift changes.

I've got heaps of troubleshooting to do, was just wondering if anyone else has come across the same symptoms?

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Mini update. Took front propshaft/driveshaft off so it's RWD. Most the the problems are gone. The shaft itself has two stuffed universal joints which I hope to rebuild. In the process of ordering some suitable internal circlip joints from the USA. Rockford RCV 430-9, 0.791" cup, 1.285" circlip-circlip. I know, strange measurements for a metric Jap car... Did ask locally about getting the shaft rebuilt and they said they'd have to weld new yokes in (which might have clearance issues) and $850. $1450 from Nissan for a new replacement shaft and front diff flange (our shafts are discontinued and they only have later ones available with different flange on the end).  

Once that's done I'll put it back in and see what happens- oh and change transfer fluid as well.

Doesn't explain the funny gearchanges though.

Checked my tyres and they are all the same size (albeit on different width rims) so I don't think they are causing an issue.

Edited by andynogo

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Driveshaft people should be able to fit universals - after all they can do it on cars with no circlips by machining existing yoke. Ask around for other driveshaft specialists.

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2 hours ago, KiwiRS4T said:

Driveshaft people should be able to fit universals - after all they can do it on cars with no circlips by machining existing yoke. Ask around for other driveshaft specialists.

They can but you can't find the right size uj's in Oz. They are available in the USA so I have two on their way from Rockford. The local guys want to weld new yokes on which are bigger so may not fit our cars. I guess they don't want to order the replacement joints in from the US... They also can charge a lot more for this.... Or am I being cynical? 

I have all the gear to get the old staked joints out and fit new ones. The trick is getting them centred and with the correct amount of lash- I have a lathe and dial gauge which makes this much easier. I'll also save over 700 bux which is handy.

Edited by andynogo

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18 hours ago, andynogo said:

albeit on different width rims

How much of a difference?

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1 hour ago, niZmO_Man said:

How much of a difference?

18x8 and 18x9

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Hmm. It shouldn't be, but you could probably try running low tyre pressure on the front to see if there's any change.

I wouldn't chance it with AWD systems and run identical wheel/tyre all round.

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I'm actually going to do a rolling circumference test on the fronts and rears to see if there's any difference. Could always try to find another set of those wheels and use the 9's all round as the 8's sit way inboard at the front- using 20mm spacers to get them out a bit so 25mm/1" would be perfect I reckon.

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Well I cbf to do rolling circumferences... bought another set of rims instead! So now have the 9"rims all round with identical tyres. At least I can rule tyre sizes out of the equation!

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Replaced the front uni joint in the front propshaft. There's another story just in that- circlip grooves not machined correctly in the joint bearing caps. That took a while and lots of swearing to figure out. Can't replace the rear joint yet as I need another joint from the manufacturer as those bearing caps are just too far out.

Anyway so far under full acceleration I haven't noticed any of the previous problems. No surging, clicking, funny gearchanges etc. I did change the transfer box fluid as well which may have helped a bit. The only thing left to do now is check for high speed vibration which I'll get round to soon. Fingers crossed!

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