anyboby know which one I need....went from 2.73 to 3.42 in a 700r4 89 iroc,

nobody can tell me....hopefully someone has done this and can remember.

thanks

 

found it on the internet one time and made it one of my favorites

http://www.transmissioncenter.net/sp...n_______va.htm

they've got about all the info you'll need.

 

Contrary to the above link, I used the 15 tooth driven and the 40 tooth drive for the same rear gear swap - this was the closest I could find from info here on TGO and other places - stock 245/50/16 tires. I did not have to get the "other" speedo gear housing that is $52 on the above page link. Also, the driven gear in the pics in the above link have the shaft installed on them, where my speedo housing had the shaft in it - but the gear just slips off this shaft, and you can put in the housing.

 

how difficult is this, I've never been inside a car trans before

 

How come when I post a question like this no one answers, lol. This info may even help me with my aftermarket t56 swap.

 

The gear swap is easy - you don't actually go inside the tranny, but only the tailhousing. You will lose some fluid though. My tranny was out anyways, so mine was easy - but - easiest way I can think of:

Jack rear of car - put jack stands on the LCA brackets (not the axles). Remove two large bolts that hold torque arm to the rear end and move torque arm. Get catch pan ready - Drop drive shaft. Put jack under tranny and hold, so that you can remove the crossmember, and remove crossmember. Lower tranny just enough to easily get to the tailhousing bolts (watch the dizzy - maybe remove the cap beforehand - it will hit firewall). Remove bolts that hold exhaust support to tailhousing. Remove tailhousing bolts, and pull it off, with torque arm and torque arm mount in tact. You'll see a clip in a slot on the tailshaft that holds that plastic gear - you have to work the clip and pull on the gear at same time - it's a bear to get it to start moving - I think I used an open end wrench large enough to go over the tailshaft, but smaller than the gear, and gently tapped the side with a mallet to work it off. Put in new gear, making sure it's clipped in correctly. Reassemble. The driven gear in inside the speedo housing - driver side, rear of tranny, round housing with one bolt that holds it in - remove it and replace gear with new one.

That sounds good anyway - someone chime in with anything I missed. Like I said, my tranny was out of car, so mine was easier. I'm trying to picture in my mind here the steps that one would need to take with tranny in car.

Also, since your there - now's the time to replace the torque arm mount and tranny mount with new (or poly) if you need/desire.

Hope any of that helps.

 

wow sounds like some work involved LOL... i gotta swap in a 4th gen rear and its 342 gears and i have 3.27's now.


that site sells housings for the gears... theres two of them... one for 34-39 tooth gears and one for 40-45's. i have a 15/39 setup now i believe, i bought them from that site... do i need to upgrade the housing too for the larger gear needed for the 3.42's?