|The 4T60-E is a FWD transmission. You are right about it being transverse and it is the original THM-440T4 except it has electronic controls. The 4L60 is the 700-R4 which is a 350 with an Overdrive. The 4L60-E is an electronic shift version. The 4L80 is an overdrive version of the 3L80 (the old 400). The 4L80-E is an electronic shift version. Below is the contents of a message I posted to the Oldsmobile list. It describes characteristics of each of GM's later transmissions.
Someone asked the question about the 4T60/65-E replacing the 700-R4. The 700-R4 is now known as the 4L60-E. The 4T60-E is a FWD tranny. The 4T65-E is new this year for the hi-po applications (Grand Prix GTP, Riviera S/C, Monte Carlo Z-34, etc). Unfortunately this will not help the racers out.
The 4L60-E (700-R4) was improved again this year. Shift quality and durability was enhanced. But the real choice for heavy duty racing is the 4L80-E or the 400. Here are some comparisons of ratings:
If you note, the engine torque rating for the 200-4R and the 700-R4 is very close in stock form. Considering the weight advantage, the gear ratio preference, deeper overdrive, and the fact that the 700-R4 only comes in Chevy bolt pattern, the 200-4R is preferable for most street applications when built properly.
Gear Ratio Chart: