As the title says, I intend to replace my worn out synchros in a 2003 ap1gearbox with brand new ap2 synchros. Labour is no biggy as I do all my work in my own garage with the help of a mechanic. PLease do not recommend me to buy a used ap2 tranny, there is nothing like that available over here and shipping from the US would kill me.

Since the ap2 tranny has the same gearing in 1st,2nd,3rd and 4th (only secondary gear is shorter), the gears,sleeves and synchros should in theory fit on a ap1 main&countershaft, right? I know these 2 items (main&countershaft) have new part#s but thats due to the change in 5th and 6th gearing. I want to keep these 2 gears as they are.


On the mainshaft I would swap the following ap2 parts :

6 GEAR SET, MAINSHAFT THIRD
7 GEAR, MAINSHAFT FOURTH



From the countershaft it should be only ap2:

5 GEAR SET, COUNTERSHAFT SECOND



Reason why I'm doing this? 430whp is one of them and the ap2 synchros are supose to be carbon nor brass.

Please let me know why it should not work so I don't waste money and time.

Many thanks in advance

 

No-one has an idea?

 

Its only been 4 hrs, Give it some time. I'm sure someone might have an idea.

 

AP2 synchros would work in an AP1 but you would have to reshim the whole tranny, pain in the ass to do but IMO well worth it.

 

what do you exactly need to reshim? also, did you state that based on your experience? I need to be 100% sure before ordering, but you gave me hope.

I say if gearing is same, shift fork is same, why would it not fit

Also why did both shafts get a new part # if only 5th and 6th got redisign and the both sit on the same shaft

 

My statement was based off what my tuner told me when i was considering doing the AP2 synchros. The AP2 synchros are alot more durable and smoother shifting from what I have heard on the boards, just really pricey to get done. Id wait for some of the pros to chime in to confirm or correct what I have said.

 

if theyre that pricy, might as well go with a whole ap2 tranny if that would be more cost effective?

 

i thought they updated the ap1 synchros to carbon and phased out the old ones?

 

They are phasing out brass synchro rings on the replacement parts. You may or may not get a carbon coated synchro with a new gear set.

 

they are not that pricey, over here they cost 5USD more per gear set than the ap1.

Yestreday I spend the evening reassembling the tranny to find out why it would not work and did not find anything. The bearing inside each gear has the same size, same possition on the shafts, same shift fork..simly everything BUT the diameter of 5th and 6th gear (due to higher gearing to compensate for shorter secondarty gear,which I dont want to change anyway) is the same, so why would I have to reshim anything? Each sleeve on my 32000miles turbocharged S is fcucked up, the teeth on the sleeves are not just muchrooming but bending inwards thus making it sometimes impossible to go in or out of a gear and the dogs on the gears are gone in each gear but 1st and reverse. 3rd gear brass synchro broke, I lost 1st as well and could not downshift from 6th into 5ft.

I never heard of a ap2 tranny having these issues and no I do never skip gears and yes I do rev match

I didn't buy a sports car to drive it like a truck from the 30s.