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4.22 vs 3.9

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kcbugeye1275

kcbugeye1275

Jedi Knight
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I've had the Bugeye 25 yrs and never been into the diff. In the last couple yrs I've scrapped a couple spridgets ad have a 3.9 and a 4.22 diff. Last night a buddy came over and with the help of a few brewskies, a big hammer and several pry bars, we got the drums off. After that getting the pumpkin out was easy. Anyway I got gskts for the pumpkin and each axle and I'm going to put the 3.9 in Sat. It seems like it'll be an easy project, but its always good to ask if there is anything I'm missing. Thanks! Oh yeah, when talking to friends you really get a strange look when you say that a friend is coming over to work on my rear end. The key word is differential. /ubbthreads/images/graemlins/cheers.gif
 
I forget which way it is but the 4.22 and 3.9 had different filler plugs. One on the diff, one on the banjo.
You will end up with no filler plug or 2 filler plugs.
If none, just fill it via the axle hole before you install the axle.
 
All the housings have a drain plug and fill plug, so you will be alright in that regard. Not much to the job really, being a racer, I got it down to about a hour taking my time. Biggest advice I can give you is let the silicone cure and completely dry before refilling the rear end.
 
Got it done, It was an easy and enjoyable sat afternoon project. The bugeye with the 4.22 had a fill hole in both the housing and the pumpkin. The 3.9 didn't have a fill hole. With the 1275 I have, the higher ratio's performance by myself was like the difference of riding by myself to carrying a passenger. Not much, but a little. I don't know if I'd keep it if I wasn't going to do an engine switch this winter, but I think it'll work out okay then. The car is a lot quieter at 75mph (3750rpm) vs (4000rpm).
 
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