[fast68]

on the 87-91 LJA coded 3L80HD transmissions found in the c10 pickups with 305 TBI engine what is the maximum pressure in the fluid cooling lines to the radiator ?
(transmission in original untouched stock form)
or at least an average guess-timate ?

lower line is the high side output to cooler on th400 right ??

also does anyone happen to know any gm vehicles that had tail end of tranny to axle u joint yoke distance of 71" -give or take 1/2" ?

the c-10 longbed 2wd trucks '73-87 with th350 9" tail were 74" i know and i have many of those driveshafts in my shafts pile.

replacing this with 3L80HD in which were 27 spline but total length of 34.5" in which is 3.5" longer than the th350 in these trucks.

all i have is the matching two piece driveline from the same 87 pickup the 3L80HD came from, but no way to mount carrier under the 78 c10 its going under. so.......
hmmmm.,......


thanks!

[fast68]

ttt still need to know thanks

[curtis73]

Can't speak too intelligently on this, but the most pressure I've seen in a tranny cooling line for GM autos is about 40 psi.

[fast68]

oh,


only 40 ???!


wow!


nice to learn thanks!


i was thinking so much higher pressure was generated by transmission pumps


wow...


hmmm....

really??

[cobalt327]

Originally Posted by fast68

oh, only 40 ???!

That's the cooler line pressure- the line pressure in the tranny can be upwards of 150-200 psi, just not to the cooler.

[curtis73]

Yep... the pressures that are generated by the pumps are very high, but they only use 30-40 psi to send fluid through the cooler.

[fast68]

ohhh ok good to know then


thanks!