Has anyone fitted the 3.9 final drive themself ?

Looking to do this as a DIY project, but was wondering about shims etc when rebuilding the diff. They are available in various thicknesses, & I take it you only know what size/s you need when you are putting the thing back together, so does this mean you have the diff in bits till you can get the required thickness shims? or would you just buy a selection in advance?

I have all the tools I think I would need, bearing pullers, slide hammers, magnetic DTI guages etc & can make drifts & any jigs needed, so I think I can strip & rebuild it OK myself, but was wondering if there are any pitfalls I have not thought of...

 

SEARCH button my friend!! There is a good 10 fourms about the 3.9 final drive!

 

You will need a service manual with all the clearances from Nissan. You will need gauges for measuring your throwout and such to make sure everything is where you need it. Do you have any reservations about taking the differential in to a dealer and having them do it??

 

Yes, I thought I had read most of them already. Couldn't find anyone describing how they got on doing it themselves though. If you can point me to one about shims & how to DIY, please do

If you had read the threads on the UK 350z site about peoples experiences with UK dealers, you might not want them to even change a spark plug for you, let alone rebuild your diff... hence I wondered if I could DIY.

I'll be importing the bits from, more than likely, Performance Nissan, so if I can get all the bits I need in one go that would be good. If I go into a dealer here and start asking for diff shims, well I can imagine the blank look on his face now

 

If you have the tools you should be set...

but... there are many many different size shims you will need to have handy for the install... Alot of people purchase all the shims, do the install and return the ones that are not used...

There are about 16 different sizes... They are not cheap either... That would be the biggest issue...

I can find the tollarnces for you...

Its hard for you to purchase all the shims and then return the un-used... we usually do that for local customers...

 

Yeah, there is a lot to choose from . I'll look into getting shims from over here but, importing again, may well be quicker though.

I was looking at changing the bearings as well, but at $175 is this essential? (9000 miles on mine)
Does this normaly get done on a FD swop or do most people reuse the old ones if on a low mileage?

Have you had much feedback from those that have done this themself as to how they got on with it?

 

Most people use new bearings...

I havent had any customers who did it on their own... most local people we sent to a gear shop we work with...

Even with the gear shop some bearings were damaged during removal of the factory pinion and the side bearings... so in some cases, you are stuck getting them anyway...

You definatly need a new Pinion Nut and Spacer Housing (crush sleeve)

Let me know if you need the part numbers for the different size shims...

 

it is well beyond the scope of most DIY'ers..unless they R&R trannies and diff's all day long for a living.

 

OT...Would the 3.9 void my warranty.

 

no mod voids your warranty...

but, if you go to your dealer for a problem with your rear end because of a noise (could be from installing with shims too big / re-use bearings) then it would not be under warranty...

but, with a part like this, 99% will now know you put anything different in the car...

 

Ah, my misunderstanding. When you said "A lot of people purchase all the shims, do the install and return the ones that are not used..." I thought you were talking about regular people DIYing, not the guys from a gear shop

So parts needed would be...

Pinion gear & ring gear $850
Side Bearing x2 $85
Side Bearing Oil Seal x2 $12
Drain Plug Washer x2 $3.90
Final Drive Gear Bolt x10 $20
Final Drive Side Gear Cir-clip x2 $1.40
Pinion Shaft Oil Seal $8.95
Pinion Shaft Crush Sleave $9.50
Pinion Nut $5
Front Pinion Bearing $34.95 (Item & price from 350evo's site)
Rear Pinion Bearing $54.95 (Item & price from 350evo's site)

Couldn't find the Front Pinion Bearing & Rear Pinion Bearing on PNP's website, I guess they can supply them OK or that I just missed them

So about $1085.65, plus whatever shims. Anything I've forgot? I'm asuming you can reuse all the driveshaft, halfshafts, & pumpkin nuts & bolts?

 

front and rear pinion bearings are a nesessity?

 

when changing the pinion gear these have to be pressed off the old one... Depending on how good you or your installer is at pulling them off, you may need new ones... alot of gear shops will not stand behind the work if they are re-using parts because you dont really know if the bearing is going to be noisy until installed again...

 

Subscribing. Should be an interesting thread.

 

How much is the total installation???

 

around $400 for install and another $80-$100 for the misc. parts you need

 

QQ, The shims are only available from nissan? My ring and pinion arrived today with oil seal, front and rear pinion bearings, housing spacer, pinion nut. I didn't buy any shims, any decent shop should know where/how to get the shims, right? I hope my local dealer has some in stock as I'd like to get this installed this week...

 

Pre-made yea...

But any experienced gear shop can cut their own shims...

Most likely your local dealer will not have in stock...

if you find out the sizes you need, we can overnight them for you...

 

Thanks Jason, thats exactly what I was hoping.

 

Got prices from UK Nissan stealers for bearings & seals etc. For example, the rear pinion bearing is the equivalent of $103, side bearings $70 each think I'll be importing all these bits as well then

They have never heard of a 'shim kit' & couldn't find it on the parts system at all. I won't tell you how much they wanted per individual shim

Diff/gearbox shops are quoting about $840 in labour alone, if I supply all the parts needed, bearings, seals etc...

Would save me a lot of time to get someone else to do it for me, but it won't be cheap

Decisions decisions