I can offer another perspective (having used T-176, T-177, a jeep auto, a T-18(granny low, not all T-18s are), a MT-8 (GM granny low 5 speed), a BA5-10 (pukejunk), and a T-5);
The t-176/177 are medium torque car style four speed (but is a top loader, used in pickups and jeeps) with a low gear that is too high. They do shift well, quickly and easily and stand up moderately well. The T-177 has a slightly lower first gear (but still too high).
The Jeep autos were pure junk (had them in 2 different Jeeps) giving lack luster performance on the street and very poor performance off road (replaced one hoping to get acceptable performance and got the same result).
The T-18 (I believe that most Jeep t-18s were not the granny low version; to get the granny low we transplanted Ford gears into it) was a poor street four speed (it is a moderately heavy truck transmission, afterall) to use it on the street you start out in second and call it a 3 speed. It shifted poorly (like a lage truck) at all times and was also only moderately good off road, as the unsyncromeshed first prevented downshifting without double clutching and the first gear was rarely used off road (first is too low for most trail work and second is often too high). This transmission is nearly impossible to shift quickly enough to avoid loosing momentum on hills. Note; shifting on hills should not be attempted; the consequences of a missed shift can be fatal.
The MT-8 Muncie Getrag was too long but geared reasonably well and drove well on and off road, the length severely limited the drive shaft angles (avoid this one, its a pain fabbing the stuff to make it work).
The Peugeot BA5-10, or maybe it was 10-5, (made by a French bicycle company) was a terrible idea on Jeeps part and not suitable for use anywhere (they break way to easily).
The T-5 transmission (coarse spline 6 cylinder Jeep version, do not use the finer spline 4 cylinder version it is too weak). It is a low torque rated transmission suitable for use in properly geared jeeps driven competently. It is not for drag racing or road racing in stock form. Jumping on the gas at every stop light will break it, as will the ram and slam style of off road driving. If driven competently it will stand up well behind 258s, 4.0s and short stroke (low torque) v-8s, as long as the axles are geared properly for the tire size. I do not recommend it for younger drivers.
The overdrive 5th gear gives acceptable street mileage and the first gear is adequate for street and off road use on moderate trails.
Note; for lower gearing on both the T-176/177 transmissions and T-5; 4:1 transfer case gearing is recommended to be used on more than moderate trails and obstacles. The use of a properly geared transfer case reduces the off road stress on the transmission and give all of the advantages with none of the disadvantages of a granny low transmission. The Dana 30 front and the AMC 20 rear (2 piece axle flanges) are more prone to breakage due to the extra torque multiplication if used with grippy tires.
Don't get bent out of shape these were my results yours my vary...
...a well prepped, well driven, vehicle should do well in any terrain, including the highway.
Carburetors became obsolete during the last century... do what ever it takes to get fuel injection...It makes bigger grins off road.
Last edited by Happy Joe; 01-08-2010 at 09:18 AM.