C4 IRS questions
 

Hi, I'm Brent.

I've searched the forum, but didnt find answers to my questions.

I'm looking to buy a complete C4 IRS to put under a F-body camaro. I looked at one last night from an 84, but found stress cracks in the diff housing. I believe it to be a D36.

Which years have a diff housing that will swap over? I don't want to buy the wrong one if I go this route.

Also, being as the cracks werent really bad, should I consider trying to weld them up? My buddy is a profesional welder with access to good equipment. The cracks were towards the top on the driver side where the webbing ends. Is this a common problem.

Moderator, I accidentally posted this in the C5 section. Please move it to the C4 technical. Sorry for the trouble.

You could use any year but if you're looking to buy everything from one car I believe I might be shopping for newer '89+ parts. Anything '87 or earlier will have shoe in rotor e-brake and if you stuck with '89+ they have an actuator in the rear caliper for the e-brake.

If you've a high horsepower/torque engine you may want to make sure you're shopping for a D44 that's more substantial. An 8 1/2" ring gear vs 7 1/2" stuff. You can mount your IRS anyway you like and hang the knuckle/spindles where appropriate for what ever wheel/tire combination you wish and adjust the width with the half-shafts.

Do you have a car that you're using for a "mule" or are you just doing a from scratch build?

I would think you would want to avoid an '84 - the exception being if you stumbled upon an '84 with a 3.31 axle ratio and it would be quite valuable. There's not many out there so I wouldn't get excited. Do you know if it was out of an auto or a manual trans car?

I'm going to have one for sale in a couple months. It's a one off rear I built. Has Dana 44 that's rebuilt. I can supply brackets to weld in your car.

Ok. When the time comes shoot me a price and hopefully it will be within my budget.

Not sure what you mean by mule, but we are putting it in a 75 camaro.

What is the advantage of the caliper with the e-brake verses the shoe in rotor e-brake? Will these have different track widths?

All 84's have the D36 rear diff. A d36 is IMO not worth the time, effort or $$$ to weld up if cracked. It is not common for them to crack unless they have been hit hard in a wreck... side impack collision on the wheel usually pushed the wheel/hub/halfshaft into the side of the housing and can crack them in that area or break the C-Beam mounting pad.

All the diff housings from all years are pretty much identical and interchange 100%.

Like WVZR1 said the later model stuff has a much better parking brake system.

The early model cars 84-88 also have a narrower track width which could be a good or bad thing depending on what wheel offset you want to use.
Will

Mule would be a car of the same type that the same or similar has been attempted on and your effort is to improve on it!

I don't believe you need to be concerned with the track width. I believe you'll hang three components, the differential, the right/left knuckle/spindle combinations where your wheel/tire combination fits into the body and THEN you will have half-shafts built/shortened to connect the three components. I would think in the long run the later caliper/e-brake combination would be to your benefit. Many more sources for replacement parts.

I'm also thinking the caliper e-brake will be better for playing. You know. To spin the rear end around and drift.

We don't have wheels yet so I could buy them at what ever offset needed.

Guess I need to keep looking for an 89 or newer d44. I'm in no big hurry.

thanks for the advice yall.

Where are you located? I have enough NOS and new parts to put together a D44 with either a 3.54, 3.73 or a 4.10 ratio. All new either GM or Dana/Spicer. I also have the left and right knuckle packages.

NOS is probably way more expensive than finding a used rear end, but feel free to put some prices together. I haven't gotten as far as deciding what gears to run. We are going to build a de-stroked hi rev engine.

I'm in Tulsa, ok 74115.