Early vs. later transmission longevity?

[CathodeRayTube]

i guess my questions pertain to this so il just add on to this thread insted of making a new one. i am seriously planning to replace the 3A with a diesel engine and build my waste vegitable oil fuel system. the engine will be either a toyota 2C-T 2.0l turbo diesel wich i have located, or a VW diesel of some kind, probably between 1.6 and 1.9l, with custom engine mounts and trans adaptor...

my question is wich tranny & final drive would be better suited for this? im thinking the older one with the 3.7 ratio because of diesels typical low speed power and lower revving nature...alltho i belive the small diesels im considering for the conversion can run at around 4k rpm normally for high speed highway driving just fine...but idk how that will affect fuel economy...what tranny and greaing do you think would be better for a diesel? is there any differance between wich one is physically stronger?

[splatterdog]

The torque of a diesel could push highway gears but, higher gears in the 83-84's will put more stress on the trans which may not like that extra torque. It's harder for a trans to turn 3.73 gears than 4.10 Think of a longer lever...

Any way you look at it,old or new T4wd, with a torque increase you will have to pussyfoot it to not grenade the hardest to find part in your car. For long term reliability you will most likely have to ditch 4wd and go with whatever your donor motor was meant to do- fwd or rwd.

If you are doing this for the ultimate goal of mileage, 3.73 is a no brainer. Donor ratio would also be a consideration though.

A while back someone here by the name of Teddy threw out the ridiculous price of $700 for a donor motor,labor,custom machining w/materials,heavy trans massage,etc for a vw conversion. Then promptly disappeared when asked to back that up. viewtopic.php?f=2&t=4471
I think he forgot more than a zero....

[CathodeRayTube]

700 or 1000 doesnt seem all that rediculos ...if you go with a junkyard engine and do the labour yourself, i know a few people who might be able to do the custom mounts etc for the cost of the metal itself...local tech schools, and my best friend is a mechanic at a toyota dealership...but IDK...with all the extra little crap that you dont think of right away that price could climb pretty quick...

i remember reading that thread. i also remember reading about having a preemptive rebuild done on the tranny and having everything hardened etc...i think i may just pay and do that.

what part of the tranny actually seems to fail or be the weakest? input shaft?