TheSamba.com :: View topic - Baja bugs for Volkswagen virgins: The IRS transmission

Fri Sep 27, 2013 9:59 pm

Can anyone tell me what this trans axle code means? CA 041 4945 The trans axle is a 3 rib type 2 IRS. I have looked all over the net and still have not found an answer.

Tue Nov 26, 2013 4:07 pm

Here you go ---
Bus Information
CA - CD 68 - 71 / 002 5:38 / 3 Rib
CE - CL 72 - 73 / 002 5:38 / 3 Rib
CM - CN 74 - 75 / 002 4:86 / 5 Rib
CP - CX 76 - 79 / 091 4:57 / 6 Rib
Serial Number Information
CM02 10 3
CM = Leter Code
02 = Day of Production / 2nd day of month
10 = Month of Production / October
3 = Year of Production / 1973

John 0\ ! /0

Wed Nov 27, 2013 6:10 am

if it's a CA it's probably a '68. if it's a 68 you don't ant it. one year only, unobtainable parts.

I believe '68s have to vast Phillips head screws holding the side cover on, later 002s have 6 bolts

Sun Apr 27, 2014 11:55 pm

Such good Info! Thanks for all of the hard work Mal, these threads are great and I've had my baja for 13 years.

Sun Jun 22, 2014 1:43 pm

Hi,

I've been searching for info on this for a couple of hours, so if anyone can help I would REALLY appreciate it.

I have an (unknown history) swing axle trans in a fiberglass buggy. I need to know if it is likely to have a 6, or the later 8 bolt differential housing.

Here is the number: 7147701

Anyone know what year that might be and if it is likely to be a 6, or an 8 bolt???
Thanks a bunch in advance,
vwpilotbob

Sun Jun 22, 2014 1:52 pm

Welcome to the Samba!

That is a late '64 transaxle and will be a 6 bolt ring gear and carrier. The R&P ratio will be a 4.37:1.

Sun Jun 22, 2014 5:59 pm

Hi, and thanks for the welcome and the info.

Would you mind sharing your source for future info?

I checked the differential ratio on this trans, and it is 4.125. So, it looks like I won't really know what is inside until I pull it apart. Bummer!

Thanks again,
vwpilotbob

Sun Jun 22, 2014 7:23 pm

Not many transaxles left that have not been apart at some time or another.

If you sort through the "Technical" drop down above in the tool bar, then go through VIN Numbers for a Type 1, you can see the sequence and judge about where yours was made.

How did you discover it was a 4.12 ring and pinion?

Mon Jun 23, 2014 11:59 am

Yeah, that's a neat trick I learned a while back.

Put the engine with zero degrees straight up, or mark the engine pulley at a point straight up.

Jack up only one side of the rear of the car.

Now make a mark on both the brake drum and the brake backing plate on the jacked up side.

Put the car into SECOND gear.

Now start turning the engine over until the brake drum makes exactly one full rotation. Count exactly how many turns of the engine pulley it takes to accomplish the full turn of the drum.

Exact turns of the crank:

4 = 3.88 gear ratio
4 1/4 = 4.125 gear ratio
4 1/2 = 4.375 gear ratio

Cool huh? I've tried it on a number of transmissions and it has been correct each time.

vwpilotbob

Tue Jun 24, 2014 6:34 pm

It's easier to drain oil - pull bottom plug - mark a tooth on ring gear with paint - then count the teeth on Ring gear ---- 35 = 4.37 / 33 - 4.12 / 31 = 3.88 --- never wrong.

John

Fri Jun 27, 2014 5:34 pm

What trans do I have if it's a D0 in a 65 swing axle notchback? I dont see this code in the list?

Thu Sep 11, 2014 7:36 pm

One question, I have a DC code gear box, is that bus or bug?

Tue Oct 07, 2014 2:48 am

Can anyone tell me if all 4.12 ring gears are 8 bolt, or were some made with 6 bolts as well??

Thanks!
vwpilotbob

Tue Oct 07, 2014 4:08 am

Fltblkbaja wrote: One question, I have a DC code gear box, is that bus or bug?

Used with 1500/1600cc from 8/68 in type 3 IRS

Sun Nov 30, 2014 10:42 pm

anyone ever use a 4.375 ring and pinion with 1.26 3rd and 0.82 4th, stock height tires and put about 100hp behind it? seems like it would have the good take off but be faster in the high gears, with still reasonable about of power.

Mon Dec 01, 2014 8:11 am

[quote="bluebeetle63"]anyone ever use a 4.375 ring and pinion with 1.26 3rd and 0.82 4th, stock height tires and put about 100hp behind it? seems like it would have the good take off but be faster in the high gears, with still reasonable amount of power.

vwpilotbob, I believe all 4.125 ring and pinions came with 8 bolts stock.

Mon Dec 01, 2014 11:23 am

[quote="bluebeetle63"] bluebeetle63 wrote: anyone ever use a 4.375 ring and pinion with 1.26 3rd and 0.82 4th, stock height tires and put about 100hp behind it? seems like it would have the good take off but be faster in the high gears, with still reasonable amount of power.

vwpilotbob, I believe all 4.125 ring and pinions came with 8 bolts stock.

I've used TALLER offroad tires with a 4.37 diff and stock gear ratios and about 100hp. EZ to light up the rears on takeoff, but it was rather long between 2nd-3rd and 3rd-4th. The engine needs to have a fairly wide power band. Stock diameter rear tires are fine for pavement, but tend to be a drag offroad (as in "drag the bottom of the car on any little obstacle").

Mon Dec 01, 2014 7:09 pm

I'm building a daily driver and would like to keep stock tires in the rear. The reason for my questions is I like being able to get caught up to traffic quickly with the 4.375, but I would like better top speed. Top speed is fine with the 4.375 and stock gears, but I don't like how high it revs. I want to make the car have good mpg if I can. so if there are holes between 2-3 3-4 I'm still curious about the gears I mentioned. Anyone think there will be a hole between the gears?

Tue Dec 02, 2014 10:56 pm

I guess that would help

Wed Dec 03, 2014 5:17 am

then you'll need an actual trans code not a part number like you listed ^