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The following information I've gathered over the years from transfer cases I've either had, worked on, or just seen in my travels. It basically answers the question "what transfer case can I use to replace my broken one?"
The short answers are;
Syclone owners can use cases from 1990-1995 Astro/Safari and the case from the 1991 Bravada
Typhoon owners can use cases from 1993-1995 Bravada/AWD Blazer. I have not confirmed if the 1992 Bravada case is the same, but I believe it should be.
The only part an owner my need to swap over would be the front output flange for the propshaft. Syclones and Typhoons both use the same size flange, which GM lists as 4.5" (it actually measures 4.25"). GM also lists the flange on the Bravada case as 5". Another twist is that if you look up a replacement transfer case at salvage yard, they list the flange sizes as being 3.5" or 4.5", but just so everyone is clear, as long as the output shaft is the correct number of splines for your application, it should be a safe purchase because the flange can be swapped, in fact the "guts" of all of these cases are interchanable.
The short answers are;
Syclone owners can use cases from 1990-1995 Astro/Safari and the case from the 1991 Bravada
Typhoon owners can use cases from 1993-1995 Bravada/AWD Blazer. I have not confirmed if the 1992 Bravada case is the same, but I believe it should be.
The only part an owner my need to swap over would be the front output flange for the propshaft. Syclones and Typhoons both use the same size flange, which GM lists as 4.5" (it actually measures 4.25"). GM also lists the flange on the Bravada case as 5". Another twist is that if you look up a replacement transfer case at salvage yard, they list the flange sizes as being 3.5" or 4.5", but just so everyone is clear, as long as the output shaft is the correct number of splines for your application, it should be a safe purchase because the flange can be swapped, in fact the "guts" of all of these cases are interchanable.
| GM Number | BW No. | Group | Years | Models | Trans Flange | Out. Flange | Out. Spline | Tail Housing | Length | Front Case | Rear Case |
| 15648651 | 4472-01 | 100 | '90-'95 | Astro, Safari | 4.13" | 4.5" | 27 | 13-72-066-901 | 5" | 13-72-039-901 | 13-72-065-901 |
| 15989331-DA | 100 | '90-'95 | Astro, Safari | 4.13" | 4.5" | 27 | 5" | 13-72-039-901 | 13-72-065-901 | ||
| 15672918 | 4472-04 | 100 | '90-'95 ('91) | Astro, Safari, Brav. (Sy) | 4.13" | 4.5" | 27 | 13-72-066-901 | 5" | 13-72-039-901 | 13-72-065-901 |
| 15963557 | 4472-09 | 100 | '90-'92, '94-'95 | Astro, Safari | 4.13" | 4.5" | 27 | 13-72-066-902 | 5" | 13-72-039-901 | 13-72-065-901 |
| 13-72-066-902-C | 5" | ||||||||||
| 15959501 | 4472-?? | '93 | Astro, Safari | 4.5" | 13-72-039-901 | 13-72-065-901 | |||||
| 15685141 | 4472-06 | 102 | '93-'94 ('92-'93) | Blazer/Bravada (Ty) | 4.13" | 5" (4.5") | 32 | 44-72-066-901-B | 6.9375" | 13-72-039-901 | 13-72-065-901 |
| 15960128 | 102 | '95 | Blazer/Bravada | 4.13" | 5" | 32 | 44-72-066-901-B | 6.9375" | 13-72-039-901 | 13-72-065-901 | |
| 15703287 | 103 | '96-'97 | Blazer/Jimmy/Bravada | 4.90" | 32 | 44-72-039-903 | 13-72-065-901 | ||||
| 15703287-DB | 103 | '96-'97 | Blazer/Jimmy/Bravada | 4.90" | 32 | 44-72-039-903 | 13-72-065-901 | ||||
| 15026806 | 4472-13 | 103 | '96-'97 | Blazer/Jimmy/Bravada | 4.90" | 5" | 32 | 44-72-039-903 | 13-72-065-901 | ||
| 15026806-NX | 103 | '96-'97 | Blazer/Jimmy/Bravada | 4.90" | 5" | 32 | 44-72-039-903 | 13-72-065-901 | |||
| 15998931 | 4472-11 | 101 | '96-'98 | Astro, Safari, Bravada | 4.90" | 27 | 13-72-066-902 | 44-72-039-903 | 13-72-065-901 | ||
| 13-72-066-902-C | |||||||||||
| 15998991 | 101 | '96-'98 | Astro, Safari, Bravada | 4.90" | 27 | 44-72-039-903 | 13-72-065-901 |