Question about differences between G28.10 and G28.12 manual transmission
05-07-2014, 04:15 AM
#1
Advanced
Thread Starter
Join Date: May 2012
Location: Eindhoven (The Netherlands)
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
Question about differences between G28.10 and G28.12 manual transmission
Hello,
I’ve got a question about the manual gearboxes,
Recently I bought some spare parts for cheap from a 85. Between these parts was also a manual gearbox.
A G28.10, and as far as I can find out, this is gearbox has the Borg Warner style synchro’s and the for the 1,2,3,4 & 5th gear the same ratio’s as the G28.12 gearbox I have in my 87 S4.
But the part numbers from the gear sets do not match. What are the differences between these gearboxes, other than a different ratio of the ring and pinion and a different outer diameter of the input shat bearing?
That make the part numbers from the individual gear sets differ?
In other words, what parts of this G28.10 gearbox can I use in my G28.12 gearbox?
Thanks in advance,
Sander Baas
928 S4
The Netherlands
I’ve got a question about the manual gearboxes,
Recently I bought some spare parts for cheap from a 85. Between these parts was also a manual gearbox.
A G28.10, and as far as I can find out, this is gearbox has the Borg Warner style synchro’s and the for the 1,2,3,4 & 5th gear the same ratio’s as the G28.12 gearbox I have in my 87 S4.
But the part numbers from the gear sets do not match. What are the differences between these gearboxes, other than a different ratio of the ring and pinion and a different outer diameter of the input shat bearing?
That make the part numbers from the individual gear sets differ?
In other words, what parts of this G28.10 gearbox can I use in my G28.12 gearbox?
Thanks in advance,
Sander Baas
928 S4
The Netherlands
06-18-2014, 12:26 PM
#3
Addict
Rennlist Member
Rennlist Member
There is 50 page factory document which explains changes between '84 vs '85 and '85 vs '87 gearboxes. It says these are different between '85 vs '87.
Stronger transmission case
Low-friction tapered roller bearings for the pinion
New final drive ratio: 29 : 11 (was 30 : 11)
(adaption to higher engine power)
Improved servo arresting for shift operations
Stronger gear wheel sets
Stronger intermediate gear with shouldered intermediate gear shaft
Stronger bearing on input shaft (now 100 mm dia., was 92 mm dia.)
Easier installation of reverse gear wheel
Even though gears have same number of teeth and critical dimensions are same they are not same. Later version is stronger. Many '85 parts can be used in later box but its probably better to change entire box as one unit. Saves taking it apart at least.
Stronger transmission case
Low-friction tapered roller bearings for the pinion
New final drive ratio: 29 : 11 (was 30 : 11)
(adaption to higher engine power)
Improved servo arresting for shift operations
Stronger gear wheel sets
Stronger intermediate gear with shouldered intermediate gear shaft
Stronger bearing on input shaft (now 100 mm dia., was 92 mm dia.)
Easier installation of reverse gear wheel
Even though gears have same number of teeth and critical dimensions are same they are not same. Later version is stronger. Many '85 parts can be used in later box but its probably better to change entire box as one unit. Saves taking it apart at least.
06-19-2014, 04:44 AM
#5
Addict
Rennlist Member
Rennlist Member
7MB PDF is included in Morehouse CD. Roger has them at least. Some differencees between '85 vs '87 boxes have been discussed in here and elsewhere before. For example this comes to mind.
http://reutterwerk.com/forums/showthread.php?t=3508
http://reutterwerk.com/forums/showthread.php?t=3508