Ok, I hate my open rear end, worst part about the car, no doubt. 91 305 tbi T5 tranny, 3.07 gears i think, 10 bolt rear.

I wanna posi in there before this winter comes up when i really wont be able to move due to 1 wheel peel.

Anyways, I replaced my axles once before because the old ones were bent due to a previous owners accident. And that time the pinion bolt sheard off making the job a great P-I-T-A!

Assuming that DOESNT happen again, how difficult is it to install a posi or limited slip differential? I dont need new gears, just the carrier. so im asking which is better for me posi or limited slip? what should I look for when searching for a new differential? and whats a good company to buy from? and can i do this with a decent set of garage tools, i dont need a press or anything, right?

thanks,
Nick

 

swap is pretty easy and straight forward. swap gear to new carrier, install carrier, check back lash, check contact pattern and you're all set.

 

be sure and replace the axle seals...or you will be taking it apart again sooner than you like.

 

I KNOW THAT THIS PROBABLY BEEN ASKED AND ANSWERED A THOUSAND + TIMES, SO IF SOMEONE IN THE KNOW WOULD JUST HUMOR ME I WOULD APPRECIATE IT!

I HAVE THE CHANCE TO BUY AN EARLIER 80'S TRANS AM (3RD GEN OF COURSE!) DISC BRAKE REAR END WITH A DIFFERENT GEAR RATIO THAN MY CAR PRESENTLY HAS. MY CAR IS A 1992. PLUS IT IS SUPPOSED TO BE A POSI.

WILL THE ELECTRONIC SPEEDOMETER BE THROWN OUT OF WHACK BY THIS SWAP? WILL I HAVE TO CHANGE SOME OBSCURE PLASTIC GEAR SOMEWHERE IN THE TRANSMISSION?

WILL ANY 3RD GEN REAR PROPORTIONING VALVE (DISC BRAKE) WORK TO COMPLETE THIS SWAP?

ANY OTHER HEADACHES LOOMING DOWN THE ROAD FOR ME?

THANKS,

SHIPFITTER

(IF ANYONE IS OFFENDED BY CAPS LOCK, PLEASE ACCEPT MY APOLOGIES!)

 

My usual way of dealing with rude people that know it's rude to use caps lock but go ahead and rudely use it anyway, is to simply not bother answering their question, even if I could if I chose to (like I could in this case).

So, if you'd like the answer, type it so that it's not such a pain to read. Show some respect to the people you're asking a favor of, and maybe they'll be more inclined to do you the favor you want.

 

i know that this probably has been asked and answered a thopusand+ times, so if someone in the know would just humor me i would appreciate it.

i have the chance to buy an earlier 80's trans am (3rd gen of course) disc brake rear end with a different gear ratio than my car presently has. my car is a '92. plus it is supposed to be a posi.

will the electronic speedometer be thrown out of whack by this swap? will i have to change some obscure plastic gear somewhere in the transmission?

will any 3rd gen rear proportioning valve (disc brake) work to complete this swap.

any other headaches looming down the road for me?

thanks,

SHIPFITTER

 

IN MY OPINION (AND I AM SURE YOU KNOW ALL ABOUT THAT), A PERSON WHO WOULD REAM OUT SOMEONE ELSE ON THIS BOARD OVER SOMETHING AS MINOR AS CAPS LOCK (IS THIS A WRITTEN RULE SOMEWHERE ON THE BOARD, OR JUST SOME OF YOUR "TRIBAL" KNOWLEDGE?) IS THE ONE WHO IS BEING RUDE AND AN A$$.

YOU WANT RESPECT? EARN IT! YOU CERTAINLY DO NOT HAVE MINE.

DO NOT BOTHER ANSWERING MY EARLIER POST...... I AM SURE YOU DO NOT KNOW WHAT I NEED TO KNOW....EVEN IF YOU THINK YOU DO.

GEARHEADS AND CAPS LOCK MANNERS............HMM, SOUNDS LIKE AN OXYMORON TO ME.

 

No need to let him have it over the caps thing man. Its just hard to read thats all. Perhaps using you as an example was not necessary and you obviously did not care for that but a little respect goes along way for all of us.

That being said on to tech. Your stock proprtioning valve should work okay but those J65 brakes can be a real pain to get working properly. They were crap from day one and I wouldn't waste my time swapping them onto anything. As far as the speedo goes I am not certain how the calibration is done on the OEM electronic speedos so perhpas another may have smoe tips. Good luck.

 

I don't have to "earn" your respect. Remember, I'm not the one looking for information; rather, I'm the one that has the answer that you want (whether you would like to think so or not). However, if you'd like to "earn" enough of my respect for me to answer your question, then accept the suggestion we have all given you that is universally correct in written communications everywhere and not just this board or even the whole Internet, and use capitalization properly. Otherwise, alot of us who might be able to help you out, won't be bothered with people too rude to follow the rules of courteous language use, because it's simply too hard to read, and it LOOKS LIKE YOU ARE SHOUTING AT US, which is of course rude in either spoken or written communications.

That having been said, since you were at least polite enough once to re-type your post properly before unleashing the flood of invective, I'll answer it.... this time.

The early rear end, if it's a posi at all (which is not real likely) most likely has the Eaton Gov-Lock "posi" in it, which you don't want, as it has very low power-handling capabilities, and works in an unusual way; even the people with 6-cyl S trucks refer to them as the Grenade-Lock because they tear up so easy. The early rear will have the Saginaw cast-iron disc brake calipers, which suck; and additionally, have considerably different hydraulic requirements from your existing rear end, since you probably have drums. Therefore in order to have any chance of getting the Saginaw discs to work right, you'd need to change your master cyl and proportioning valve. As far as the speedo gear(s), yes you would have to change them, if the gear ratio in a replacement rear is different from your existing one. Wouldn't matter what year it is or what kind of brakes it has. That would be the same as if you changed the gears in the rear you have.

 

Just type normally and be done with it. Some of the guys here know more then you or I could ever possibly know, so its usually not a good idea to **** everyone off by typing in all caps. I mean, come on, it takes how many milliseconds to depress the shift key? On top of that, it looks foolish to type in all caps.

That would be like me going into an autoparts store and screaming at the top of my lungs:
HELL0!!! I. HAVE. A. 9-BOLT. AND. I. WOULD. LIKE. TO. GET. SEALS. AND. BEARINGS. CAN. YOU. HELP. ME?????

Do you do that in public? I dont... Im not 'reaming' you out. Im just telling you how everyone feels when someone uses all caps.

 

sounds good to me, but can you elaborate on the backlash check and contact patterns, because you lost me

thanks
Nick

 

back lash is free movement between gears use a dial indicator contact pattern is just what it says, where and how much the gears mesh together

 

Where should I look for a posi carrier, new or used? And what numbers do I have to match up?

 

For used ones, look in 4th gen Z28s & Trans Ams, and the later 3rd gen Z28s & Trans Ams (90-92).

For new ones, any of the drive train places; Drive Train Specialists, Drive Train Direct, Randy's R&P, etc. etc. etc.; as well as your local speed shop, Summit, swap meets, etc.

 

I agree and think it is the best option for any 10 bolt gear/carrier change. You might want to pick up the gear that comes with any of those carriers as well. Your 3.08 gear is for a 2 series carrier and cannot be used with any of the 3 series posi carriers stated above. You can get 2 series carriers but the cost would be much higher than going with a 4th gen take out set-up. I got my 3.42 gears for 100 bucks out of low mileage 97 LT1 car and another 100 scored me the SLP take out posi that those gears are used with. The take out posi has since been disscontiuned but there are millions of used ones out there waiting for you to buy one



It acutally is in the rules. You may want to refresh yourself on them. You want to listen to everything RB has to tell you. There is nothing that ede or himself post that shouldn't be remembered by all. They are the backbone to all of your in depth 3rd gen technical needs.

 

You can read all about replacing your open diff with a limitslip by downloading this PDF.
A dial indicator and magnetic stand is nessessary and the new differential side bearings need to be installed on the new diff , using a press.
A differential install shim service pack is needed too.
If you can read a dial indicator, use a torque wrench and follow directions, you can install it yourself in the driveway. Setting up the contact pattern is not nessessary (cause you're not changing the pinion) but setting up the backlash and bearing preload is. If i can do it so can you.

www.auburngear.com

A Powertrax is a good alternative and takes no special tools or knowledge to install.

www.powertrax.com