69 RT A36 performance axle package

[Rudderguy]

Good Day all,

Bit of a specific question regarding the 8 3/4 rear axle for the 69RT.

The car i am rebuilding is an "XS" RT car...the rear axle originally was the 2070741 "741" axle.  With the A36 package...was all the rear axles the 2881489 "489" axle with the sure grip?

Or..did it just mean that it got 3.55 gears in any axle?

Were any other axles used for that package?


Thanks


Cheers

Macdon221

[Bad B-rad]

I thought R/T cars had 742 or (in 1969) the start of the 489?
I always found 741 in small block lo po cars.

[Bad B-rad]

I think A36 is 3.55 with S.G., in one of carriers above

[69CoronetRT]

Good Day all,

Bit of a specific question regarding the 8 3/4 rear axle for the 69RT.

The car i am rebuilding is an "XS" RT car...the rear axle originally was the 2070741 "741" axle.  With the A36 package...was all the rear axles the 2881489 "489" axle with the sure grip?

Or..did it just mean that it got 3.55 gears in any axle?

Were any other axles used for that package?


Thanks


Cheers

Macdon221

The 489 case was introduced in late 68 model year.

How do you know the original axle is the 741?

[Challenger340]

Good Day all,

Bit of a specific question regarding the 8 3/4 rear axle for the 69RT.

The car i am rebuilding is an "XS" RT car...the rear axle originally was the 2070741 "741" axle.  With the A36 package...was all the rear axles the 2881489 "489" axle with the sure grip?

Or..did it just mean that it got 3.55 gears in any axle?

Were any other axles used for that package?


Thanks


Cheers

Macdon221

My understanding is that the 2070741 or 74"1" Diff Carrier "pumpkin", would NOT be original to a 1969 'XS' code Charger R/T ?
Although the 2070741 Pumpkin was used until 1972 in some models, because the 2070741 was a small 1 3/8" Pinion, it was reserved for low weight/low horsepower applications through low weight/medium horsepower and high weight/low horsepower applications.

For your XS code 1969 Charger R/T, the 2881489 Carrier Case "Pumpkin" with the 1 7/8" Tapered Pinion, was the most commonly used A36 Pumpkin, and most probable to be original to the Car, using any gearing(3.55 A36) for the Auto/Trans.
Although,
I have heard ?...... that some very early production 1969 Charger R/T models were equipped with the 2070742 pumpkins, or "742", using the 1/3/4" Pinions. (never seen it myself though)
There were even some 489 Pumpkins that used the 1 3/4" Pinions early on before all were moved to the 1 7/8" Pinions.

Long story short....
* no matter the A36 option, I believe the 741 is wrong and NOT original to your 1969 Charger R/T
* A36 option XS 1969 Charger R/T most probable is the 489 Pumpkin, but if very early production it could have had a 742

[Bad B-rad]

[/quote]

My understanding is that the 2070741 or 74"1" Diff Carrier "pumpkin", would NOT be original to a 1969 'XS' code Charger R/T ?
Although the 2070741 Pumpkin was used until 1972 in some models, because the 2070741 was a small 1 3/8" Pinion, it was reserved for low weight/low horsepower applications through low weight/medium horsepower and high weight/low horsepower applications.

For your XS code 1969 Charger R/T, the 2881489 Carrier Case "Pumpkin" with the 1 7/8" Tapered Pinion, was the most commonly used A36 Pumpkin, and most probable to be original to the Car, using any gearing(3.55 A36) for the Auto/Trans.
Although,
I have heard ?...... that some very early production 1969 Charger R/T models were equipped with the 2070742 pumpkins, or "742", using the 1/3/4" Pinions. (never seen it myself though)
There were even some 489 Pumpkins that used the 1 3/4" Pinions early on before all were moved to the 1 7/8" Pinions.

Long story short....
* no matter the A36 option, I believe the 741 is wrong and NOT original to your 1969 Charger R/T
* A36 option XS 1969 Charger R/T most probable is the 489 Pumpkin, but if very early production it could have had a 742



[/quote]




I have  also heard about the 742(size) pinion in  a 489 case, but I have never found one myself.

[Rudderguy]

You are Correct...I was only assuming the 741 was the original one because I had no other info that made me believe otherwise.

The date on the 741 case was 2 months before the car was assembled. That is what lead me to believe it was.  But maybe not.

So from what I can gather...the A36 just meant the gearing (3.55 suregrip) and had nothing to do with the "pumpkin" as they should of been a 489 case anyway?

Thx

[John_Kunkel]

I think A36 is 3.55 with S.G.

Correct, the A36 was about the gear ratio and SG but it was the large stem pinion.