ironheadvette

I'm building a 61 restomod on an Art Morrison frame. The project came with a Dana 36 with a 3:07 gear. I'm going with an LS6 with 4L60E, and I want to get to a 3:45 gear for better performance.

I had an article on someone doing a build on the 36 that made it just as good as swapping out for a DANA 44. Can't find it....

If I can get this done, I can order the new Tail-shaft for the 4L60E that supports the mechanical speedometer - but I have to specify the gears and tire size before I order.

I searched the forum but didn't see anything.
Thanks

John McGraw

I would not spend any money on the D36 rear. With the 4L trans and the limited tire size that you can put on the 61, you will never hurt it. If it was a manual trans and you were going to do a bunch of drag racing with sticky tires, then you might consider it, but there is no way to make a 36 as strong as a 44, and you would just be better off switching to a D44. The truth is, you will boil the rear tires on the car almost any time you step down on the loud pedal, so you will never generate enough torque to the rear to hurt it.

I have 3.45 gears in all my restomods except for the 67 Chevelle wagon, and it has 3.08 gears in it. The 3.45 is a very good choice for the 4L trans. It will give you great performance, but will still motor down the highway at a nice low rpm when in overdrive. I went with the 3.08 in my wagon, because I used the 6L80E trans in it, and the first gear on the 6L is way lower than the 4L.



Regards, John McGraw

ironheadvette

John,
Thanks for the reply.
I'm not sure if you are telling me to stay with the D36 with the 3:07 gears.... or change the ratio out to 3:45 on the D36.

I called on a used 44 tonight with what is suppose to be 3:42 gears. The price was good, but it has been outside for a long time, and the seller doesn't want to open it up for inspection.

I was going to find out what ratio a LS1 or LS2 with an automatic had - just to see if it is close to the 3:07.

John McGraw

The 3.45 would be a better choice on the 4L trans, but the 3.07 would probably be a better choice on the 6L trans. I have the 3.45 in both of my 4L transmission cars, and I am very happy with the acceleration. On my car with the 6L trans, the lower first gear, more than makes up for the higher rear gear.

I would not spend the premium for a D44 rear on a car with an automatic, limited tire size, and a LS1. If you were putting a 500hp motor and sticky tires on the car, it might be worth it, but not on a stock LS1.

Regards, John McGraw

jim lockwood

My (admittedly limited) experience with a D36 makes me agree with John.

My bride's track car, a D&D Grand Sport, has a D36 (and a strong TRACO 377 and a Muncie). Before we bought the car, it had been seriously abused. Think: rev engine, pop clutch, go sideways, repeat.

This continued until one half-shaft popped and the other twisted about 15 degrees. The D36 was unhurt. After getting new half-shafts, we've gone on to put 1500 track miles on it and 2500 street miles with no problems.

Bottom line: Don't be quick to dump the D36; it's not as weak as you think.

Jim

ironheadvette

Thanks Gentleman.... I think I'll stay with the 36 (I'm 90% sure it's ok).
It wouldn't be too expensive to have the gear replaced if I get it going and decide I need a lower gear.

wmf62

John
he said "I'm going with an LS6 with 4L60E" in his original post. i thought in the more recent post that he was simply asking what ratio came stock in an original car with a LS1 or LS2.

so i don't know what engine he has....
Bill

John McGraw

Yea Bill, I missed that! The advice still holds however. Without big rubber, you will never hurt that rear. Even a regular diet of drag racing will not hurt it with an automatic and the limited tire size that will fit under his car.
With a decent D44 costing 3-4 times what you can get a D36 for, I just don't see the value. The nice thing about these rears, is that they are totally interchangeable. If the D36 ever fails, you can just replace the center section with a D44 in a few minutes. With a manual trans, or a trans brake, then the D44 is warranted, as shock loading is tough on the D36.


Regards, John McGraw