th125 and 4t60

[devilz_z24]

How much trouble it it to swap the th125 to the 4t60(the one from the late 80's). I found a few fiero web sites have done this and just did a little modification to the mounts.

Well I have an 88 z24 Cavalier and know its a different engine bay. I would like to know the size difference of each one. I know custom of different axles will probably be needed and most likley the mounts.

If anybody has pics of the 2 that would be great. especially of the mounting location diffences of the trannies.

[sharkey]

i havent done it, but am trying to figure stuff out for someone else. the tranny itself is a fair bit bigger, but it will fit in the engine bay. as for mounts, you use the stock j body upper mount (as far as i can tell, it wil bolt right on). i couldnt tell you if the tranny is physicaly longer, but if it isnt, then the original j-body axles should work (the 440t4/4t60 use the same axle seals as a 125, they are the same spline count). you will have to run a vacume line for the modulator, but that pretty straight forward.

ill measure up some cores we have at work tomorow if i get time

[Quinky]

Personaly I wouldn't do it... even for the added bonus of over drive for better gas milage.. The 440t4 (4t60) are a weaker transmission then a TH-125.. they don't stand up as well..

[devilz_z24]

What was the most powerful engine GM bolted to the 4t60? It was eithet the 3.8 or the 3.4 DOHC. Thats at least 170 horses it can withstand right? What is your reasoning for saying its weaker?

[torq455]

seen the 4t60 in the older caddy's with the 4.9L V8. the 4t60 is stronger than the 125, but not by a huge margin.