Hey all, I’ve got a 1977 and wanted to confirm a question about my axle. I saw Toyota reference guides that show G code axles as 8” and F code as 7.5” but the oldest reference seems to go to 1979. Most other info I can find says 5 lug or 2wd trucks are all or almost all 7.5” axles. So what on earth is in my truck? Rockauto seems to only sell 7.5” parts, and Randy’s Worldwide only shows 7.5” as an option. Could a 1977 be had with an 8”?
Check your build plate under the hood. It should show the axle type right after the transmission type. My truck had the 8” axle (GO82). Both 8” and 7.5 inch (F292) were used in 1977. Parts for the 8” (GO82) are no longer available. Attached is my plate with the axle type enlarged.
Yes, much of the info posted out there stops at '79 as you've seen. The older trucks had the beefier 8" to my knowledge, then downgraded to 7.5" on the next generations. My 1975 is has a G102 differential -- 8" w/4.37 gearing and a w50 5spd trans
What i was told by a neighbor whos into 4x4 yotas is that the earlier 8" diffs arent swappable with the newer 8" diffs because apparently they arent a true 8".
I think I can clear up the 8” question. The GO82 is actually classified as a 3/4 ton heavy duty axle. Toyota designed this for use on ‘special service vehicles’ (cab&chassis) used mostly for motorhomes and commercial applications. The earlier 8” was just that, an 8” ring gear in a standard axle housing. I believe Toyota started using the GO82 in 1976, definitely in 1977. Getting a 4.37 instead of the 4.10 would have helped with the motorhomes. Don’t understand why they dropped it.
Any more info on this? I've seen reference to other builds that they installed a different gear ratio differential, such as those in the 3.XX ratios. I've had in the back of my mind that I'd try to find higher gearing for highway speeds than my low 4.37 gearing....but if it's not going to fit the axle housing....
