over drive tranny

[brian.b]

how hard would it be to put a overdrive trans in a 48 special....and how rare is it to find one........

[Fid]

We did it on a '48  once. It was not too bad. The rear axle ratio is different on the OD cars so we changed the transmission and the rear end.

[brian.b]

will my shifter and stuff work or is it all different........drive line lenth????thanks for the info......

[joefrazer]

Aside from the transmission and electrical components, you will need the shorter front driveshaft. Otherwise, everything else can be reused.

I added OD to my 50k and did not swap rear ends. What I lost in zero to 60 time I more than gained in fuel economy.

[brian.b]

right now my car is comfortable around 45 mph if the speedo is right but id like to get it to at leat do 55 or 60 and not have the rpms out of sight..........how does your do with overdrive.......

[Fid]

joefrazer, thanks for clarifying how it performs without changing the rear end. When we did ours, we had a spare rear end which was listed in the shop manual so we did the whole change.  I know when you go from different engine tranny types in the J it can be a big problem if you don't have the correct match but I never knew how it behaves in the big cars.  Sounds like all you miss is a bit of "off the line" acceleration. It makes sense that top end would be fine if the rear end wasn't changed.