TF 999/998 sporting internal diff from the 904 ?

rustytoolss said

First question. Does anyone know what the first year was that the 999//998 was used in production vehicles ?
Since there does not seam to be any tell tale signs of which trans you are looking at 904/998/999 externally.
How can you tell if you've got a 999/998 and not at 904 internally ?
I know the 999/998 have lower gearset. But if you do not know how to spot the 999/998, tell me what to look for ?

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The lockup 999 can be identified by two things. One is the machine ring on the input shaft that is unique to the lockup.
The second way that I identify a 999 with the low gear set is by taking off the pan and look at the back of the sunshell. The low gear set sunshell has a raised step in the back of it whereas the 2:45 is rounded smooth.
If you come across a trans that has both the machined ring on the input and the step on the sunshell you can bet it's a 999.
I don,t think they made any of those lock ups that were not low gear 999s, but I am not certain of that.