What would you do with an unknown diff?

[sradkovich]

Long time reader, first time poster,

 

I recently bought a 77 280z which has been sitting for over 12 years. I have not heard it run or seen it roll since it had seized brakes. I have taken out the differential with the intent to at least derust and paint. Considering i know nothing about differentials, i wouldnt know if there was a problem by looking at it even if it were obvious to most of you, I thought while i have it on the work bench - maybe i should get it serviced for new bearings and a good check. 

 

I spoke to a guy at a transmission shop who said that there is no reason to believe that there would be any issues just becuase it was sitting. Unless i know there is a problem with the bearings it shouldnt be fiddled with. While i appreciate his honesty and willigness to pass up business, what would you all suggest? it has ~80k miles and like i said, i have no knowledge of whether or not there are any problems. From what i can tell by rotating the tires its smooth but thats without any load. Of course ill give it new fluid but wondering how far i should go into this while i have it out. 

 

Thanks for the help

[SleeperZ]

Just 80k miles?  Change the fluid and run it.  If it leaks, replace the seals.

[BluDestiny]

Yeah they're easy enough to drop out that. I've run multiple Junkyard diffs after just changing the fluid. 

[Six_Shooter]

I agree, just flush and replace fluid, no need to waste money simply because you're not sure of condition. Diffs usually don't develop problems, especially from sitting if they are sealed up.

[Miles]

80K miles is like new!

 

All I have done with R200 differentials that I bought at a wrecking yard, was  to replace the oil seals for the  side shafts and pinion. Very easy to do.  At the same time I replaced the cover gasket.

 

Seals and gaskets are available  at Motor Sports Auto (MSA) and/or Black Dragon. Napa may even have them.

 

 

If you are new to Z cars:

 

Suggestions:

 

• Buy books/manuals for the engine and transmission you want to use.
• Download a Factory Service Manual (FSM) and buy a Haynes repair manual for your specific car.
• Download electrical schematics for your car.  PDFs are easier to read than those found in books. Some are in color.
• Buy the book How to Restore Your Datsun Z Car by Wick Humble. It will save you hours of searching for "how to" info.
• Focus on searching Hybridz as 99% of questions have already been addressed.
• Make a detailed plan with parts list including cost before starting a project. Plan every system of the car.
• Start bookmarking Z car parts suppliers - there are many!
• Remember these are 40 year old cars and will need restoration to be safe and drivable.
• Join ClassicZCars.com website and search there as well.
• Become well informed about modifications before asking questions. People will be more inclined to answer informed questions.
• Have some money. I stopped counting after $12k.
• Read the new member FAQs.

 

 Useful Links:

http://zhome.com/

http://www.atlanticz.../tech-tips.html

http://www.classiczcars.com/index

http://www.zcarparts.com/

http://www.blackdrag.../zZxCatalog.htm

http://www.arizonazcar.com/

 

 

[sradkovich]

Thanks all, ill refrain from going any deeper than refreshing the seals. This should help fund my next order to Black dragon or new rubber and bearings all around.

 

The only remaining concern i have is that when i was diconnecting from the drive shaft i had to use quite a bit of torch heat to get those bolts to budge. I've read elsewhere that using a torch near bearings can often ruin the bearing but im always skeptical of random proclimations without a lot of support to the claim. Would any of you agree that that bearing should be replaced (so that i know to include in the next order)?  I'll be working on it tonight so ill get a better idea if there is any slipping or knocking as it spins. 

 

Thanks again.