swapping transmissions

[chwright182]

my father in law has an 85 with a 4+3 transmission and we're going to swap it to the ZF 6 speed. i know there's some modifcations that need to be done but i don't know and can't find what they are. can anyone help me out? a link to the info or if you just know it would be greatly appreciated. thanks in advance.

 

[Schrade]

Welcome onto the boards there...

You need to get PeteK - frequents some of the vette forums, and would know ALL details off the top of his head on tranny tech.

 

[John Robinson]

Trans Swap

Some thoughts on what you need to know.

Is the spline the same on the ZF as on the 4+3

Is the front to back distance the same. If not then you need to modify the drive shaft length.

Do the mounting holes line up exactly. No error here it needs to perfect.

Does the shift linkage connect to the trans. You may have to shorten or lengthen them to get proper gear engagement.

 

[boomdriver]

i'd guess the mounting bolts/pattern will be the big issue. These trans come from 2 different blocks. I'm sure it CAN be done, but what kind of adaptors are required, or swapping internal mating parts.. bellhousings...
Drive shaft is nothing to fear. Measure and make a new one. balance and install. You even get the option of making one with bigger joints...The CENTER BEAM might be an issue. Not sure if its the same length on all models/trans types. Thats gonna matter.
Linkage...may need to use the entire linkage that came on the trans, some mounts welded on the chassis, but thats just a fabrication challenge, not a deal breaker at all. The linkage WILL be in about the same place, length of links because the c-4 chassis stayed the same, just eng& trans changed.

Once bolted up, the rest is just some creative engineering.
I'd enjoy seeing how that 6 performed behind the stump puller.

 

[chwright182]

thanks everyone. looks like we've got our work cut out for us. I'll let ya know how it goes.

 

[G Winter]

You will need the ZF bellhousing . I have read the shifter comes up at just a little diff location. You will need a C beam to fit also.

Glenn

 

[vetteoz]

Is the spline the same on the ZF as on the 4+3
Is the front to back distance the same. If not then you need to modify the drive shaft length.

Same 26 spline shaft
All the C4 trans ( inc auto ) are exactly same distance from block
You only change C beam / driveshaft if doing a diff swap
( D44 is 1" longer so shorter C beam needed)

ZF Swap info
http://members.cisdi.com/~anesthes/zf6/