LSD Carrier Installation, advice please

[aonghus]

This is actually for a Lexus IS300 rear end, but as the methodology for working on rear ends is pretty universal, I come to you fellas to ask advice.

I'm going to drop the housing tommarrow. My goal here is to swap the stock open differential with a stock Toyota LSD unit I bought used. From what I can tell, all I need to do is undo the bearing caps, undo the ring gear, swap the ring gear to my 'new' LSD, retorque, reinstall the carrier, torque bearing caps.

The rear end is most like a 10 or 12 bolt, nearly indentical setup, only no solid axles.

My concern is that I might be disturbing some other aspect of the rear-end, mainly the pinion pre-load. Should I be treating this as a complete overhaul? or can I simply 'swap' the ring gears from carrier to carrier, reinstall and be set?



I can't find much definitive writing on the subject, and the entire Lexus IS community basically prefers not to get their hands dirty for anything but attaching body kits of rims. :X

[chicane67]

Carrier to carrier is fine.

But, apply some paint... look at what you have before you take it apart... then spaw the carrier... reset lash to the picture you had before you took it apart.

I thin youll be fine. If you dont do anything with the pinion (which you shouldnt in this easy swap) than I wouldnt worry about pinion pre-load.

Your good man... get on with it already.

[aonghus]

That is the most straight up answer I've received in months Chicane LOL. Thats along the lines of what I was thinking, but my Football coaches always say, I get paralysis by analysis, I just say I'm being thorough!

Two things though: by spaw do you mean spin? as in apply the paint/persian blue to see the mesh pattern?

And if you could be so kind, explain what it is exactly I am resetting the lash on...



Thanks a ton dude... I'll have to owe you some beer.

[big gear head]

Because of machining tolerances you can not simply take one out and put another one in. The backlash on a ring & pinion set is set to within +/- .001 inch and needs to be kept this way. You will need to check the backlash before you remove the original differential and set the backlash back to the same number with the new LSD. You will need a dial indicator with a magnetic base to check it. Set it up like this.

You MUST hold the pinion perfectly still when making the measurements. If the pinion moves any at all then your measurements will be completely inaccurate.

[aonghus]

thank you a ton dude, thats exactly how I thought I needed to have the Dial Indicator, Its sitting on my work bench right now that way.

How does one replicate the backlash when swapping ring gear to a different carrier like I am doing?

Also, what torque spec should I be using for the bearing caps/mains?

Do I spin the differential a complete 360 degrees and write down the furthest 'runout' and that is my backlash?

[chicane67]

Nice flippin typos. Thats damn funny...

...then SWAP... the carrier. Yes, swap... the carrier.

The paint is for the mesh wipe. You wanna look at the teeth that you directly painted and the three or so areas of wipeoff around the ring gear... to give you the best look at whats up.

Freddy pretty much summed up the backlash thing... so no sense in confusing you with more typos.

I thin you got it. Thin. The brain is much faster than punching keystrokes trying to explain. whoooowie. Typo Wednesday it was.

Runout isnt a big deal unless you get a funky pattern. The setting of the lash is adjusted by... well its a Toyota third member... so depending on the year of vehicle... its either a solid shim and spanner or spanners on both sides. The spanner controls the backlash and it also controls carrier bearing pre-load. You just screw it in or out and put the lock tabs on when you get what you like.

Here is probably the best Toyota write up I have seen to date and it states 58 ft/lb: http://www.4x4wire.com/toyota/tech/gear_setup/

If you run into some problems, take the third member over to Pro Gear in KerneyMesa... and let Mark give you a little schooling on lash and set up.

[aonghus]

thank you so much.

Beers on me if ever you're in SD.

[chicane67]

How about May 6-9 ?? Ill be in Sorrento Mesa... You north, central or southside ??

[aonghus]

You have a PM.

[big gear head]

I'm not sure how to set the backlash on the rear end that you are working on. I usually only do GM, Ford and Chrysler rear ends, so I'm not very familiar with the Toyota. I did one several years ago, but don't remember how it was adjusted. Like Chicane said, it could be spanners or shims.

[aonghus]

My car sat overnight halfway out of the garage, unfortunatley my house is oriented so the garage faces the street, had to lock up all my stuff.

I figured out how to take the backlash measurement, and even to read the pattern, I could not for the life of me figure out how to change the backlash, I took the housing to Pro-Gears per Chicane's advice, Mark & Steve are pretty cool dudes. I think I shocked them a bit when I told them I don't drift, and that I own a '68.

I didn't get to watch the job being done, so I still couldn't say whether its shim or spanners. There is literally no information out there about my exact differential, and the community on my other forums has the 'let a shop do everything' mentality.

I did manage to bust a CV boot, or at least the dust/grease seal. The rubber itself isn't torn, but there was a plate that appears to be vaccum sealed and filled with grease that sandwiches between the differential and the CV that popped off (trying to lift a diff by one's self is not advisable)

Anyway, thanks a bunch guys. The car feels worlds different. Its nice to be sure where the car is heading when I step on it! LOL

[chicane67]

There is literally no information out there about my exact differential,

I did manage to bust a CV boot, or at least the dust/grease seal. The rubber itself isn't torn, but there was a plate that appears to be vaccum sealed and filled with grease that sandwiches between the differential and the CV that popped off (trying to lift a diff by one's self is not advisable)

Well... there is. That is why I always recommend to anyone that owns or is going to purchase a late model car... to purchase the factory service manuals for that car. Yes, they can be and most of the time are expensive (about $100-150/set)... but they tell you everything the factory trained tech is gonna need to know to troubleshoot any problem you have. You just get to pocket the money when you do your own troubleshooting.

Axle problems. If you run into any... about 5 miles west of ProGear on Claremont Mesa Blvd... you will find "Jarvis clutch". They do clutches and axles for imports and domestic FWD, including IRS rear drives. Chip is the man. Best quality and prices anywhere in SD for CV type axles. Mark too... would send you his way.

In fact... if you ever need advice on where to take specific things for specific needs... Mark is a walking, friggin ROLADEX of automotive contacts. Give him a call... he wont steer you wrong.

Glad things got worked out. Mark is a stand up homie.

[aonghus]

I shot the sh*t with mark for about 20 minutes, he sure is a roladex...but you seem like you are too buddy

Chicane, did you used to live in San Diego? I've lived here my whole life, seems like you know more about the shops in this town than I do!

Also, I agree on the FSM, worth every penny. I just bought the car in January, ordered the FSM a week ago, waiting for it to show up, I'm on spring break right now and decided if there was a good time for me to possibley make my car inoperable, now was it.

Anyway, thanks a ton dude, don't forget that I owe you some Beers, and hell, I think I owe Mark some too.

[chicane67]

Born and raised... 30+ year San Diego Veteran. Mostly North County, Mira Mecca, PQ/RB/Poway, Tierrasanta.

In the business, per-sey, there are those "shops" or even individual people who are known for the quality of work and the knowledge to back it up... and its a hardened, small circle. I was lucky enough to be in that cirlce... and Mark it was the one who got me in.