Interchangability of '90 4th gear with 92 cluster

[mrTachyon]

Sorry that this is the wrong form, I can apparently only post in this section...

Simple question, that I've not been able to find the answer to after a few hours of digging:

I have a chipped tooth on my 4th gear. The only spare 4th I happen to have among my parts is from the 1990-early-1991 gear set. Can I use this with a 1992+ gear set, or is the helical angle on the 1992+ intermediate shaft different?

Thank you!

 

[taz4432]

Sorry that this is the wrong form, I can apparently only post in this section...

Simple question, that I've not been able to find the answer to after a few hours of digging:

I have a chipped tooth on my 4th gear. The only spare 4th I happen to have among my parts is from the 1990-early-1991 gear set. Can I use this with a 1992+ gear set, or is the helical angle on the 1992+ intermediate shaft different?

Thank you!

If I remember correctly from when my 92 tranny crapped the bed, the 90 tranny has a smaller ID for the gears. I know at least one of my shafts in the 90 tranny I'm using had a smaller diameter than the same shaft in the 92 tranny.

If you keep all the brackets/shifter/etc. (everything except the tranny itself) from the 92 and put in the 90, it basically acts as a 'factory short shifter'.

 

[chaclark83]

Angle is the same just count the teeth and make sure they are the same. Only worry is that once the two gears have worn into each other they can wear more prominatly against another gear.

 

[pauleyman]

No they do not interchange. The hub/sleeve are different diameters. The actual gear itself is the same pitch from 92 up but the smaller teeth for the synchros are all different. If it's 1992 maybe. I'd have to look but definately cannot mix 90-92 4th with 93-94 4th. if you have a 90-91 4th that may be the same as 92. It's 3rd gear that the pitch changes. Not sure about 4th but I don't think it changed pitch.

 

[mrTachyon]

No they do not interchange. The hub/sleeve are different diameters. The actual gear itself is the same pitch from 92 up but the smaller teeth for the synchros are all different. If it's 1992 maybe. I'd have to look but definately cannot mix 90-92 4th with 93-94 4th. if you have a 90-91 4th that may be the same as 92. It's 3rd gear that the pitch changes. Not sure about 4th but I don't think it changed pitch.

Thanks for the response.

But for reference, the hub and slider between 3 and 4 are the same between 1990 and early 1992, in late 1992-1999 it went to the larger diameter synchro and hub.

I have an early 1992 input cluster set with the smaller 1990 - early 1992 synchro hub and slider setup. It can be identified as a late 1991 early 1992 because it has 3 notches on the 3rd gear teeth vs none for the 1990 - early 1991.

I guess to simplify what I need to know is do you know what changed between the 90-91 intermediate shaft and the 1992+ intermediate shaft?

Thanks again!

 

[pauleyman]

The 90 and 91 intermediate shafts are the same except for the diameter of the needle bearing surface for first and 2nd gear and of course the splines for the hub. You use a 91 intermediate to get a 2nd gear double cone synchro to work in a 90 trans if you're not changing a bunch of other crap. The 3rd gear pitch was the same on 90-91. The diameter between the two gears also increased but that doesn't affect interchangeability. The 3rd gear pitch changed on 92 up intermediate shafts.