I'm going to bounce this off of anyone here, to see if anyone has done a 4L80E swap with aftermarket controller in a 98, and if anyone has run into any clearance issues.

I know the length from the bellhousing to the mount is off by 1 11/16" from the TH400 to the 4L80, but I don't know which tailshaft variant we have, so I don't know the difference in overall length, yet.

I'm wanting to do the OD swap, because my long-term goal for my car is to be a good, solid, mostly-stock driver that will get okay gas mileage on long trips, and I think the OD will go a long way to doing that, while cruising at interstate speeds.

Any suggestions?

 

Your car came with the "long" tailshaft TH400, however this is actually the mamma bear middle tailshaft. The really long pappa bear tailshafts were used on trucks. Your problem with the 4L80E fitment isn't overall length (you'll need a custom driveshaft anyway). The problem is that the case is much larger in diameter for longer than the TH400. This is because the 4L80E basically takes the TH400 internal parts, moves them backwards, and puts an O.D. gear set and clutch pack between them and the converter. Slide your TH400 about six inches back and see how it fits. Yeah, I realize that's not a good comparison because the bellhousing would hit the firewall, but you get the idea.

 

i will agree.i have one laying on my floor right now and a th400 looks like a powerglide next to it.

 

Aren't the 4l60 and 4l80 transmissions meant for Chevy engines? I thought the BOP pattern is long gone!

 

all it takes is an adapter plate