Transmission identification
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| − | = Preamble = | + | ==Preamble== |
This page is to acquaint people with the identification of popular North American transmissions based on pan shape, case outline, and OEM numbering. This page also offers overall dimension, gear ratios and number of gears available in each transmission, and originating year, make and model. | This page is to acquaint people with the identification of popular North American transmissions based on pan shape, case outline, and OEM numbering. This page also offers overall dimension, gear ratios and number of gears available in each transmission, and originating year, make and model. | ||
==Casting numbers== | ==Casting numbers== | ||
| − | ==Date codes== | + | ===Date codes=== |
The date code format varied, but one date code that was used has a letter followed by two or three numbers. The letter is the month. The next number or two numbers will be the day of the month. The last number is the last digit of the year. | The date code format varied, but one date code that was used has a letter followed by two or three numbers. The letter is the month. The next number or two numbers will be the day of the month. The last number is the last digit of the year. | ||
:Example: '''C124''' | :Example: '''C124''' | ||
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[[File:TH2004RBell.jpg]] | [[File:TH2004RBell.jpg]] | ||
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Rear view of a TH2004R transmission with BOP design bellhousing bolt pattern. Notice the valley between the top two bolt holes. | Rear view of a TH2004R transmission with BOP design bellhousing bolt pattern. Notice the valley between the top two bolt holes. | ||
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====Identifying transmissions in the TH700R4 family==== | ====Identifying transmissions in the TH700R4 family==== | ||
| − | [[File:TH700-R4_ID.jpg]] | + | [[File:TH700-R4_ID.jpg]][[File:700 k case.jpg|350px|right]] |
| − | Reportedly there are three different TH700R4 cases. | + | |
| + | Reportedly there are three different TH700R4 cases. The marking (if any) are found cast into the bellhousing on the passenger side. | ||
*There is a case with no markings, it is the weakest and should be avoided for high performance duty | *There is a case with no markings, it is the weakest and should be avoided for high performance duty | ||
There is an '''MD8''' case, it's considered suitable for most performance duty | There is an '''MD8''' case, it's considered suitable for most performance duty | ||
| − | *Then there is the '''K''' case, it is the strongest TH700R4 case | + | *Then there is the '''K''' case, it is the strongest TH700R4 case (shown above, right) |
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*[http://www.transmissioncenter.net/700r4.htm TH700R4/4L60 info] | *[http://www.transmissioncenter.net/700r4.htm TH700R4/4L60 info] | ||
===Fastener threads=== | ===Fastener threads=== | ||
| − | LX engine tranny to block bolts are metric: M10 x 1.5. | + | LX engine tranny-to-block bolts are metric: M10 x 1.5. |
Using SAE bolts on a GM transmission mount after about 1978 will strip the mount threads. GM converted to metric mount bolts about 1978 even though most of the rest of the transmission bolts did not change until the TH700R4 and TH4L80/E came out. | Using SAE bolts on a GM transmission mount after about 1978 will strip the mount threads. GM converted to metric mount bolts about 1978 even though most of the rest of the transmission bolts did not change until the TH700R4 and TH4L80/E came out. | ||
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