22. Identifying Marks on T5s

All T5s originally came with an identification tag attached to an extension-housing bolt. The tags can be deciphered, however, due to the modularity of the T5 the tag may not match the contents. It may be easier to identify the application of a GM T5 by some of its unique external characteristics.

22.1. Year of Manufacture

The year of manufacture can be found in the center of a circle on the main case and on the extension housing (Figure 22-1, Figure 22-2).

Figure 22-1: Year of Manufacture Main Case

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Figure 22-2: Year of Manufacture Extension Housing

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22.2. GM vs. Ford

All GM T5s (1983-1992), except T body (Chevette), have a standard GM bellhousing bolt pattern. All Ford T5s have a bellhousing bolt pattern that looks similar to that of a Top Loader, though it is different.

All 1983-1992 GM V8 T5s have a 26-spline  1⅛-inch input shaft, a 2.95:1 first gear ratio, and a standard GM bellhousing bolt pattern. All Ford T5s have a 10-spline  1116-inch input shaft.

GM V6 and 4-cylinder T5s have a 14-spline  1-inch input shaft, either a 3.50:1, 3.76:1, or 4.03:1 first gear ratio, and a standard GM bellhousing bolt pattern. Avoid these transmissions for V8 applications; they are weaker than the V8 transmissions. There is no 10.5-inch clutch disc available for this transmission, only a 9⅝- and an 11-inch disc.

Beginning in 1993, there was no T5 available with the GM V8. All fourth generation F body T5s have a Ford T5 bellhousing bolt pattern (Figure 22-3). The 26-spline  1⅛-inch input shaft is similar to the earlier V8 input shaft, but the pilot is longer than that used in the earlier models (Figure 22-4). The front bearing retainer is the same as used on the 1983-1992 GM T5.

Figure 22-3: Fourth Generation F Body T5 Front View

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Figure 22-4: Fourth Generation F Body T5 Input Shaft (left) vs. Earlier Input Shaft (right)

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22.3. World Class vs. Non-World Class

A World Class T5 can easily be distinguished from a non-World Class T5 by the examining the front countershaft bearing race. The non-World Class T5 countershaft rides on flat roller bearings that are retained in a stamped steel shell, which has a smooth outside surface (Figure 22-5). The World Class T5 countershaft rides on tapered roller bearings. The front bearing race is cast and is embossed with a bearing number; e.g., Timken LM67010 (Figure 22-6).

Figure 22-5: Non-World Class T5 Front Countershaft Bearing Race

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Figure 22-6: World Class T5 Front Countershaft Bearing Race

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All GM T5s manufactured from 1983-1987 were of the Non-World Class design. From 1988-1992, all GM F body V6 and V8 T5s were of the World Class design, but T5s designed for the other GM vehicles, such as the S10 truck, were still of the Non-World Class design.

There was an obvious structural change in the front face of the main case between 1983 (Figure 22-7) and 1985 (Figure 22-8), but no further change between 1985 (Figure 22-8) and 1988 (Figure 22-9). The transmission-to-bellhousing pattern remained unchanged.

Figure 22-7: 1983 T5 Front View

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Figure 22-8: 1985 T5 Front View

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Figure 22-9: 1988 T5 Front View

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Originally Released 11 February 2002

updated 27 August 2007