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FAQ BoardThis board is where some of the most informative and helpful Frequently Asked Questions we get here at ThirdGen.Org are put for easier reference. This IS NOT a general question board.
Same goes for third gen and 4th gen cars, heck even second gens.
The same rear end was used with all engine combos, the only difference will be the gear ratios.
Most of the time the 6cyl cars got lower gears to make up for lack of torque from engine. So truth be told, for a performance based build it may be best to start with a good 6cyl. car rear end.
Yep, 3.42 was the highest gear option and the Torsen differential was the highest posi or limited slip option. Here is a video of how the Torsen works. Pretty awesome design.
Ive been searching and searching but i havent been able to find a solid answer or i might have over looked it on accident. Im going to be putting a 4th gen axle in my 89 camaro that already has stock rear disc brakes and im wondering if i can reuse my original calipers and caliper brackets on the 4th gen rear end? Or am i going to have to but 4th gen calipers and brackets?
If the 89 is a 9 bolt rear then i dont think you can if its a 98-02 rear. May need a different backing plate. The 93-97 supposively had same brakes as the 9 bolt z28/iroc cars in the late 80's. If its a 93/97, try the bracket/backing plate and see if it lines up
How strong is the torsen rear? What brakes? axles? the torsen?
Same strength as any other 10 bolt. Torsen is just the brand/style of the posi unit inside, which are all inherently weak because if the small 7.5" ring size.
Hey man! Just got my first Firebird. Drove it 5 hours home started having humming noise from rear end half way home. Got it home and took it to a buddies shop and the rear end is toast. I am just going to be putting in a new rear axle. But I can't see your swap pictures. Was wondering if you could show me?? I got a 88 Pontiac Firebird Formula 350 Trying to get it done asap and the 4th gens are a lot more common around here.
Got a quick question. My dad got a rear from a 02 car. He acquired it in hopes of using it for another project. He has decided to do something different and asked if i wanted it. He doesn't know anything other than it's not limited slip and it has disc brakes. I'm gonna get it from him but wondered if it would be worth just swapping the disc onto my drum rear? Assuming the backing plates bolt up. My rear is drum and a 3:08. If this one is the same ratio as mine higher I'll swap the whole assembly. May seem pointless to most of you but my main thing is to be able to get disc on the rear and it's free so I'm entertaining the thought.
Got a quick question. My dad got a rear from a 02 car. He acquired it in hopes of using it for another project. He has decided to do something different and asked if i wanted it. He doesn't know anything other than it's not limited slip and it has disc brakes. I'm gonna get it from him but wondered if it would be worth just swapping the disc onto my drum rear? Assuming the backing plates bolt up. My rear is drum and a 3:08. If this one is the same ratio as mine higher I'll swap the whole assembly. May seem pointless to most of you but my main thing is to be able to get disc on the rear and it's free so I'm entertaining the thought.
I had to get a new rear end that isn't posi and has drums. I'm waiting for a posi to pop up before I swap the disc back on. I do agree get rid of drums. But if those fears in that other one are 342 or 373 I swap the whole thing
Someone help needed! I think i found a good deal, please give me a insight for im only 19, on craiglist near me soneone is selling a g92 rear end with disc brakes, says comes with new brake pads, and e brake line, for 350. Ok price ? Good invedtment? For i have stock rear end and drum brakes
Someone help needed! I think i found a good deal, please give me a insight for im only 19, on craiglist near me soneone is selling a g92 rear end with disc brakes, says comes with new brake pads, and e brake line, for 350. Ok price ? Good invedtment? For i have stock rear end and drum brakes
Seems a little high to me, unless it's really low miles. In my area (Central North Carolina) those typically sell for $200-$250. I actually just bought one last week. 3.23 Gears, G80 Limited Slip, G92. I only gave $100 for mine, complete with calipers, sway bar, etc. I did not get e-brake cables with it, but I'd likely want to get new ones either way.
Someone help needed! I think i found a good deal, please give me a insight for im only 19, on craiglist near me soneone is selling a g92 rear end with disc brakes, says comes with new brake pads, and e brake line, for 350. Ok price ? Good invedtment? For i have stock rear end and drum brakes
yeah that's high man. I pulled one from a junkyard for 100 bucks with a 35 dollar core charge
If its a 9 bolt out of a 305 tpi 5 spd car it could be the rare 3.45 gear. It be worth it. 10 bolt? I wouldnt pay more than 300 for one with 3.23-3.42 gear and fresh brakes
i looked at all three pages and I'm not going to lie I'm tired lol
its been over 8 years since this post was up. I have a all original 90 Iroc vert a4. i have a 4 channel rear end out of a 95 camaro auto. its a complete unit, but my biggest question is how did you guys adjust your speedo? i have 2:73's and am going to 3:23's. I have a few friends that did this swap but with 98+ rear ends but changed the dash and went with dakota digital to fix their issue. I'm planning on keeping mine stock. Thanks in advance
Cable speedo cars are easy, just change the speedo gears. The electronic speedo might need the digital box signal adjuster stuff. My 91 z28 i did had 2.73 factory and vss electronic speedo. Gm did make two vss style speedo gears, one for 2.73 and one for 3.23 i believe. My 10 bolt was 3.23 so it was easy to buy the gm gear for the trans. If you did a gear ratio out side of those then you were screwed lol and needed a signal converter.
i just mounted my Irocz spare and it seems to fit over the LS1 brakes..but the clearance is VERY tight... you definately might want to grind some of the caliper mounting bracket for more clearance (see arrow in pic)..but it does seem to work. see pics
the spare is supposively a full size spare for the 16x8 Irocz rims. i'd be very happy if i could use it since my 9 bolt broke and i will be using the ls1 rear i have layin around
The easiest way (if it's still in the car) is based on model year. 1993 - 1997 is LT1 & 1998 - 2002 is LS1
If it's out of the car, the calipers would be an easy identifier if they're still on it. The LT1 calipers look the same as the late 3rd Gen PBR calipers.
If all else fails, pull the cover off the diff. An LT1 (93-97) will have an Auburn Clutch-type Posi Unit. An LS1 (98-02) will have a Torsen LSD Posi Unit.
Hope this helps some.
Great discussion and 4th gen conversion walk through. I have done mine now (83 Camaro) and all went well. Amazing improvement to braking with all new disc brakes assemblies for 97 Firebird car stops far better than before, I even purchased new E cables for the original 97 Firebird my axle came out of, made some cuts / welded the ends back on and presto! worked great! These message boards are PRICELESS so THANKS.
With that said, NOW my issues are finding some wheels that pull the tires in slightly from the outside of fenders (maybe 3/4") and push the now WIDER tires in to take advantage of all the new found "inner space". I read about 4th gen wheels, Corvette wheels etc. etc.This is a "toy" to have fun with (and it has been so far) so cost is at a premium, LOL Any thoughts? THANKS AGAIN.
Thanks great read. I completed my 4th gen rear end swap (97 Firebird into 83 camaro Z28) all works great! The braking is amazingly better however, one problem, the red brake light on my dash stays on all the time when key is on / engine running. Is this a pressure differential in the proportioning valve? Also the E brakes are all hooked up and working perfectly, Any thoughts?
"The pressure differential warning switch is designed to constantly compare front and rear brake pressure from the master cylinder and energize the warning light on the dash in the event of a front or rear system failure. The valve and switch are so designed that the switch will latch in the "warning" position once a failure has occurred. The only way the light can be turned off is to repair the failure and apply a pedal force to develop approximately 450 psi line pressure."
I assume the wiring is attached to the combination valve.
"The pressure differential warning switch is designed to constantly compare front and rear brake pressure from the master cylinder and energize the warning light on the dash in the event of a front or rear system failure. The valve and switch are so designed that the switch will latch in the "warning" position once a failure has occurred. The only way the light can be turned off is to repair the failure and apply a pedal force to develop approximately 450 psi line pressure."
I assume the wiring is attached to the combination valve.
JamesC
Wow, that was quick Thanks James. Yes everything is connected, and all is working great. So it sounds like I will have to replace the proportioning valve with a 4 wheel disc unit? I must add the car has NEVER stopped so well, and the pedal feels great. THANKS!
Yes, sounds like I will be doing some serious investigating into this. Biggest thing is, the brakes work GREAT! But the safety equipment needs to operate properly. I believe the proportioning valve is not as much trouble as the SAE / Metric, so i think cutting and flaring with new metric ends may be in the future.
Think I may start with a 97 valve as that is what the rear end came from.
I wrote another similar thread before (now edited to this) and decided that since i just did the swap, i would clean that post up and add more info and pics. This is what i know about the rears and swap from lots of time searching and my recent experience.
The 4th gen rears retain all of the third gen stuff, all shocks/springs, panhard bar, lower control arms and such.
If you lower the car, get an adjustable panhard bar to recenter the rear… if not it will kick out on the driver’s side. Mine did that with an eibach pro-kit.
LT1 and LS1 A4 cars had either 2.73 or 3.23 rear (gotta check that out) and T56 cars had a 3.42. The LS1 rear is preferred in a lot of cases because of the brakes that usually come with it. They are pretty big at 12inch and big single piston calipers and work good. Up until '99, the 10 bolts had Auburn posi units..(from the best of my knowledge) which is a clutch type posi that needs limited slip additive. 99+ Ls1 cars had Zexel Torsen differentials which are great for strip performance. Although some SS model cars from 99+ did have options for the Auburn unit. Zexen diffs dont have clutches which can wear out in a short amount of time. Just another advantage of the zexel differential.
The 93-97 4th gen rears are 3.8" wider from hub to hub so the stock thirdgen wheels will stick out some. A lot say that its even with the fender lip so its not all that bad. Some stick out abit past. the 98+ rears are abit shorter, at about 3.5 inches wide they say, but my measurements are showing more like a 3.125 inch difference. LS1 rear is about 64 3/4inch long and 9 bolt was 61 5/8. Below you can see my pics, its even with the fender lip.
Also, the rears are available with traction control or without out it. These are called 4 channel rear ends for traction control, and 3 channel rearends without traction control. Since thirdgens don’t have ABS or traction control it really doesn’t matter which type rear you get performance wise. However the brake lines on the rear will be different. The rears with traction control and abs have split separate lines and don’t connect to a T block like the 3 channel and factory thirdgen disk brake rears...so if you get a 4 channel, you’ll want to run new hardlines from the calipers to a T block on the rear end, just like factory thirdgen disk brake cars have. You should be able to reuse your factory disk brake cars rubber line and Tblock and just screw in the new hardlines to the 4thgen calipers. Several members have done this. (82-83 cars might have different fittings for the hardline on the car from what I read, so you might wanna check that) Just measure the new hardline lengths, which should be about 18-20inch on the drivers side and 26-30 inch for the passenger side. Check which type fitting ends they have. i'm not sure on this one. Also check to see if your factory lines will work…I have heard it works as well.
3 channel rearends have brake line setups like our thirdgen cars. The lines run from calipers and meet at a T block on the rear and the rubber line from the T block just screws into the factory thirdgens hardline fitting. My rear was a 4 channel but I had 3 channel lines put on. My car is a 89 with 9 bolt rear end with factory PBR calipers/11.65 inch rotors . LS1 rear was direct bolt on from suspension stuff to the brake lines. i reused my stock proportioning valve and the car seems to stop great! just like before if not better now!
For the drum rear to 4th gen conversion, you can use the stock 3rd gen master cylinder...some have even used the stock-proportioning valve with out problems. However it wouldn’t hurt to put in a disk rear proportioning valve or an adjustable one from summit racing or wildwood. I’d recommend it. You will need the proper brake lines from the calipers to the T-fitting at the rear. You should be able to keep everything factory from that fitting forward just like the disk brake cars above. This comes from the research on this site I have done, so the hardline fittings on the drum car must be the same as the disk cars. The rear brake lines and the parking brake are the only things you'll need to modify when swapping to a 4th gen rear
Now for the stuff that don’t work….like I just mentioned, the only thing that isnt a bolt in deal is the ebrake cables. For that to work, you need to make a bracket to hold the 4thgen cables to the top of the trans tunnel.. or get different cables and mod them to work
LS1 98+ rears go here for Ebrake cable info. It covers part numbers, custom brackets and such. Basically, The Bendex P/N# C1621 are the ones to get, but I guess they are discontinued? So use Tru-Torque# C94597 which are 1460mm long. Page 2 of the bottom link goes into good detail on these cables and mods. Also you can use the stock LS1 cables if you mod them as mentioned in the link. I am not running cables yet, and probly will be buying the ones mentioned.
If you have a 93-97 rear, go to a parts store like advance auto, or pep boys or whatever, and ask for e-brake cables for a 90-92 camaro with rear discs. this will give you the right cables. you'll need two. The 90-92 F-bodies used identical rear disc brakes as the 93 to 97 4th gens. A lot of ppl use the 91 or 92. Get the first design, as there are two I believe.
Few pics at the bottom of this thread… describing stock wheels sticking out
Jack up the rear of the car and support the body with 2 jackstands.
Place 2 jackstands under each of the axle tubes.
Remove the wheels
Remove the 2 long bolts the hold the torque arm to the pumpkin on the rear end
Move torque arm to the side or pull it off
Unbolt the driveshaft from the rear end, leave it in the tranny and lay the end on the ground being careful not to damage it or knock the end caps off
unbolt the sway bar from the rear
you can leave the sway bar attached to the endlinks but it will make it harder to move the rear end out from under the car
remove the brake lines from the drums
unbolt the lower control arms from the rear end
unbolt the brake line "T" from the rear end, if you are changing the brake lines, remove the lines from the "T" before unbolting it
unbolt the shocks from the rear
using the jack under the rear end, carefully balance it and jack it up a bit and pull the shocks out of the rear end, shocks will just hang there.
move the 2 jackstands that were under the rear end.
As you carefully lower the rear end, grab the coil springs as they will start to fall out.
roll the jack with the rear end out from under the car and place it somewhere.
Put the 4th gen rear on the jack and roll it under the car.
jack it up about level with the shocks and place the jackstands under the rear.
Position the springs back on the perches and carefully jack the rear up
Bolt up the shocks
Bolt up the Lower control arms.
And just start bolting everything else back up.
I just picked up a 2002 3.23 rear end and I need help with what I may need. Just trying do as much research as I can, I purchased koni yellows to.go with the rear end as well as umi weight jack kits, I know you said I'll need an adjustable panhard bar. What else would I need? Torque arm? Subframe connectors? Can I still put a sway bar on? If anyone could help me out that'd be amazing.
I just picked up a 2002 3.23 rear end and I need help with what I may need. Just trying do as much research as I can, I purchased koni yellows to.go with the rear end as well as umi weight jack kits, I know you said I'll need an adjustable panhard bar. What else would I need? Torque arm? Subframe connectors? Can I still put a sway bar on? If anyone could help me out that'd be amazing.
Everything will bolt right up to the 4th gen rear. Ebrake cables are the one thing that are a pain to figure out.
Ok, I know this thread is pretty old, but I'm hoping someone has the answer and can put it here with the rest of the info.
I bought a 97 LT1 Camaro rear end with the stock single piston brakes, it had a 2.77 ring gear in it that I upgraded to 3.42 with a Detroit TruTrac carrier which cost more than I was willing to pay but got it done by a shop.
Anyway getting to my questions, I had to get a different uni joint to connect it up to my tailshaft, a 1350 to 1344 (3R) conversion joint because the Yoke on the axle was different, so that was fine, but now I've found the bolts holding the straps for the uni-joint don't fit this one.
They will go in about 3 or 4 threads and then lock, and more pressure and they'd snap or cross thread, so I wanted to know what the 3rdgen rear end 4 bolt threads are, and if anyone knows the 97 4th gen yoke bolt sizes I'd need to get this installation done?
If I am understanding you correctly, It sounds like you simply dont have the correct bolts for your 4th gen replacement rear end "yoke". I would call the shop who did your rear gear work, and ask them if they have the correct ones, or swing by the junk yard with a pic, one of your old bolts, and an explanation of what you have. Wish you good luck, and man will that gear change "wake-up" your car.
If I am understanding you correctly, It sounds like you simply dont have the correct bolts for your 4th gen replacement rear end "yoke". I would call the shop who did your rear gear work, and ask them if they have the correct ones, or swing by the junk yard with a pic, one of your old bolts, and an explanation of what you have. Wish you good luck, and man will that gear change "wake-up" your car.
Sorry I always forget to mention I'm in Australia, and these cars are fairly rare here, i.e. most auto-stores and mechanics have barely heard of them, and now days its 18 year old checkout operators that don't even know about cars.
Old bolts were 7/16" head, around 1.5" long with about 1/4 inch non-threaded.
Looks like the new yoke takes a similar size bolt, I was thinking maybe they switched from imperial to metric?
The first 4 threads of the bolt looked to be flattened down.
I had the same issue. I had to get a tap and clean the holes out. They would go in about the same as your saying and just stop. After I ran a tap thru them they went in perfect. They kept the same thread the whole way from 82-02.
Last edited by Fullmonte77; 02-13-2022 at 08:48 AM.
Ya wow, that changes a lot, hard telling what your Aussie car has (has to be cool though to have one of the greatest cars their) with this said now, I think I would go to the hardware store (or equivalent) get several bolts with closest threads also take your existing bolts and use their thread checker to establish what you have, then test fit a few similar size that are most likely metric, to correct establish size.
My 83 (here in the states) does have "mostly" metric however, their are some Freedom measurements as well. Good luck, GREAT car, and I know you folks enjoy your great cars as well, I watch several you tube videos (like the boys on mighty car mods) Good luck Mate!
Thanks guys.
Yeah I did think about running a t5ap through but haven't had the best of luck with those.
@Fullmonte77 Do you recall what size it was?
I'm assuming it's 5/16-24 UNF?
I tried spraying some penetrant and winding the bolts in and out to try and clean but that had no effect.
Yes should be 5/16”-24. Just take your time and you will be fine. Since they are fine thread any little bit of rust or junk in there will keep them from going in right.
Yeah, so far I haven't been able to find anything from 82-02 that doesn't use 5/16 fine threads for the uni straps so unless it's an aftermarket yoke that didn't both to put their branding on it, I should be good.
I've got the tap so I'll give it a try this afternoon with plenty of lube and see how it goes.
So I cleaned up the threads in the yoke and there was a fair bit of crap in there. I also ran the bolts through the die and everything went in and fit perfectly....
Except the conversion joint. Two problems with that.
One was that the conversion joint was the wrong way round (3R end was for the diff yoke with the 2 inner C clips to hold it in, tailshaft end was for the 4thgen aluminum style)
Luckily I figured this out during the attempt to remove the old uni with butane torch and hammer....
I ended up dremmeling out the staked nut on the diff yoke, and boosting the **** out of the compressor with a rattle gun and got the yoke off and switched it out with my old diff to get back to a 3R/3R setup.
What a pain in the ***, but at least now the 4th gen diff is all attached and in. Now for the rest of the project.
Thanks for the help guys.
So I cleaned up the threads in the yoke and there was a fair bit of crap in there. I also ran the bolts through the die and everything went in and fit perfectly....
Except the conversion joint. Two problems with that.
One was that the conversion joint was the wrong way round (3R end was for the diff yoke with the 2 inner C clips to hold it in, tailshaft end was for the 4thgen aluminum style)
Luckily I figured this out during the attempt to remove the old uni with butane torch and hammer....
I ended up dremmeling out the staked nut on the diff yoke, and boosting the **** out of the compressor with a rattle gun and got the yoke off and switched it out with my old diff to get back to a 3R/3R setup.
What a pain in the ***, but at least now the 4th gen diff is all attached and in. Now for the rest of the project.
Thanks for the help guys.
Bad thing is now you lost your preload on the pinion bearings. When you remove the yoke you need to replace the crush sleeve and redo your bearing preload.
Bad thing is now you lost your preload on the pinion bearings. When you remove the yoke you need to replace the crush sleeve and redo your bearing preload.
FFS
It's always something...
When i took the original yoke off the old diff i just removed the nut with a tiny bit of torque and the yoke slipped off with a light tap.
The reco'd diff that was done by the shop I had to bash away like crazy with a mini sledge to get it off.
I'm assuming worst case scenario is I've rattle gunned the yoke back on too much and will get bearings binding?
Or too loose (I don't think that happened LOL) and have too much play...
Do you need to fabricate a bracket to hold the cables if your 3rd gen is a 4 wheel disc car? My 88 has the G92 in it and I just bought an 01 rear end but lost on the ebrake cables. I have a sloped driveway so I must have ebrakes
I used all the original mounts and isolator rubbers, but had to adjust the length of the original cables, I would look at replacements from Hawks or? As I am not happy with the performance, and in your case if the brake is needed, not strong enough, not mount related, but simply needs to be shorter without welding the upper Y point ends back on the cables. In two words - "Adjustment issue"
01-16-2016, 06:54 AM
