Is the A8 tranny same as the A6 4.2 (Tip.)tranny?
04-17-2003, 05:50 PM
#3
From a quick look, the 3-letter tranny codes are totally different.
I don't know how much of a difference that makes.
PaulW recently visited the ZF plant in Chicagoland that does rebuilds, and knows a lot about the trannys in general, let's see what he has to say.
I'll take a closer look at the manuals in the AM, for now I'm fading. Night all!
PaulW recently visited the ZF plant in Chicagoland that does rebuilds, and knows a lot about the trannys in general, let's see what he has to say.
I'll take a closer look at the manuals in the AM, for now I'm fading. Night all!
04-17-2003, 08:54 PM
#4
AudiWorld Senior Member
Join Date: Mar 2003
Posts: 1,184
Likes: 0
Received 0 Likes
on
0 Posts
Re: basically yes. they are both 5hp24a zf transmissions.
the audi 01l tranny is the zf 5hp24 family in the "a" guise inclusive of the transfer box, torsen et al.
torque converters are usually different due to differeing torque requirements for the motors, and there are a number of other detail changes.
hth,
dave
'01 s8
torque converters are usually different due to differeing torque requirements for the motors, and there are a number of other detail changes.
hth,
dave
'01 s8
04-18-2003, 09:28 AM
#5
Junior Member
Join Date: Oct 2001
Posts: 501
Likes: 0
Received 0 Likes
on
0 Posts
Effective final ratios vary ... don't plan on a match, danger danger.
This is probably why the 3-letter tranny codes are different, per JimR.
If you are planning on swapping an A8 tranny unit to a 4.2 A6, you have to be very careful. Do not take my word on the below info, make sure through your own research.
Some background -
The effective final drive of the 2000+ 4.2 A6 matches the effective final drive of the 97-99 A8's, but it will not match for a 2000 and above A8 or an S8.
I have no idea how the S6 Avant plays out.
Internal ratios are similar. As an aside, the basic transmission internal workings are the same for the high-torque MB and BMW five speed auto applications.
The effective final drive is a function of both the "final" ring and pinions and the intermediate gear set from the torsen. Interestingly, a manual transmission S4 or a manual transmission euro S8 doesn't have an intermediate gear set.
>>>> The intermediate gear set is the stumbling block. Auto transmission V8 Audi's rarely have the same ring and pinion in the front as they do in the back. Even more fun, the S8's are not close to having a "perfect" match from front to back, Audi probably used that as a tuning aid.
Once again - If you are planning on swapping an A8 tranny unit to a 4.2 A6, you have to be very careful.
If you are planning on swapping an A8 tranny unit to a 4.2 A6, you have to be very careful. Do not take my word on the below info, make sure through your own research.
Some background -
The effective final drive of the 2000+ 4.2 A6 matches the effective final drive of the 97-99 A8's, but it will not match for a 2000 and above A8 or an S8.
I have no idea how the S6 Avant plays out.
Internal ratios are similar. As an aside, the basic transmission internal workings are the same for the high-torque MB and BMW five speed auto applications.
The effective final drive is a function of both the "final" ring and pinions and the intermediate gear set from the torsen. Interestingly, a manual transmission S4 or a manual transmission euro S8 doesn't have an intermediate gear set.
>>>> The intermediate gear set is the stumbling block. Auto transmission V8 Audi's rarely have the same ring and pinion in the front as they do in the back. Even more fun, the S8's are not close to having a "perfect" match from front to back, Audi probably used that as a tuning aid.
Once again - If you are planning on swapping an A8 tranny unit to a 4.2 A6, you have to be very careful.
04-18-2003, 12:06 PM
#7
AudiWorld Senior Member
Join Date: Mar 2003
Posts: 1,184
Likes: 0
Received 0 Likes
on
0 Posts
Re: 3 different ratios
it is not as tricky as it sounds...
there are 3 ratios for the 01l transmissions: 30/11, 32/11 and 34/11 - irrespective of whether these are for an a6 or a8.
you will need to match this ratio with an appropriate ratio in the rear differential. there are 3 ratio sets on the rear: 35/9, 37/9 and 37/10.
the matches are pretty easy to determine using the family albulm. for instance on the s8, a 34/11 tranny matches with a 37/9 final drive.
dave
'01 s8
there are 3 ratios for the 01l transmissions: 30/11, 32/11 and 34/11 - irrespective of whether these are for an a6 or a8.
you will need to match this ratio with an appropriate ratio in the rear differential. there are 3 ratio sets on the rear: 35/9, 37/9 and 37/10.
the matches are pretty easy to determine using the family albulm. for instance on the s8, a 34/11 tranny matches with a 37/9 final drive.
dave
'01 s8
Trending Topics
04-18-2003, 05:20 PM
#8
Junior Member
Join Date: Oct 2001
Posts: 501
Likes: 0
Received 0 Likes
on
0 Posts
Agreed on the numbers ...
... but in general, my point is that someone planning this does have to do the homework.
As an example, if someone did not know what you know, could they read this post of yours and be able to tell what this means -
34/11 tranny matches with a 37/9 final drive
Stated another way, what is the intermediate step gear set to make this 4.11 work with a 3.09, and how do the automatic S8's net a 3.73 effective?
As an example, if someone did not know what you know, could they read this post of yours and be able to tell what this means -
34/11 tranny matches with a 37/9 final drive
Stated another way, what is the intermediate step gear set to make this 4.11 work with a 3.09, and how do the automatic S8's net a 3.73 effective?
04-18-2003, 06:44 PM
#9
AudiWorld Senior Member
Join Date: Mar 2003
Posts: 1,184
Likes: 0
Received 0 Likes
on
0 Posts
Re: more details...
audi specifies the "ratio" of the transmission based on the intermediate gear ratios. this is *not* the transmission ratio.
irrespective of the car, the overall transmission ratio is the same as that of the rear differential. sorry if i didn't make that clear in my earlier post.
wrt the rear drive, this is simply the result of the transmission ratio. wrt the front diff, it must also include the intermediate gears - which audi lists in the family album.
audi does not specify the individual pinion ratios of the front differential in the zf transmissions - as these are supplied by zf as part of the transmission.
dave
'01 s8
irrespective of the car, the overall transmission ratio is the same as that of the rear differential. sorry if i didn't make that clear in my earlier post.
wrt the rear drive, this is simply the result of the transmission ratio. wrt the front diff, it must also include the intermediate gears - which audi lists in the family album.
audi does not specify the individual pinion ratios of the front differential in the zf transmissions - as these are supplied by zf as part of the transmission.
dave
'01 s8
04-18-2003, 07:19 PM
#10
Junior Member
Join Date: Oct 2001
Posts: 501
Likes: 0
Received 0 Likes
on
0 Posts
I forgot to also say "thanks" for contributing to this topic ...
A while back (maybe a year??) many of us tried to validate the combinations to figure out how we could get the torque multiplication of the S8's with our A8's.
I stumbled on the auto S8 combo's by accident, cross-referenced in information on A4 configs. Not the actual parts, purely the ratios. My sources for both were the Bentley's, which in some areas are dated (for my copies).
As an aside, the only real reason I even have an A4 Bentley was to understand how to possibly swap the six speed out of an S4 into the A8. On this topic, all I have ever wanted was for someone to give me a build sheet ... and I got quite frustrated with the tuners simply telling me that all I had to do was go to the Audi dealer and order the parts.
If you happen to have the specific part numbers for the auto S8 set-up and could share them, many of us would be extremely interested !!!
I stumbled on the auto S8 combo's by accident, cross-referenced in information on A4 configs. Not the actual parts, purely the ratios. My sources for both were the Bentley's, which in some areas are dated (for my copies).
As an aside, the only real reason I even have an A4 Bentley was to understand how to possibly swap the six speed out of an S4 into the A8. On this topic, all I have ever wanted was for someone to give me a build sheet ... and I got quite frustrated with the tuners simply telling me that all I had to do was go to the Audi dealer and order the parts.
If you happen to have the specific part numbers for the auto S8 set-up and could share them, many of us would be extremely interested !!!