Inliners International Forums General Discussion Drive Train th2004r with 3.38 rear

Hi! I posted last week asking about trans options for my 62 lwb chev truck. I looked at a lot of standard options but came across a really nice th2004r for cheap. If anyone has ideas about mount options, interference with and modification of the torsion bar cross member let me know. The rear end was changed from the 3.90 to a 3.38. With a 2.54 first gear and a 261 six how will the truck peerform?

I would like the 3.90 rear end myself, especially with an overdrive transmission like the 2004R. The launch would be much more fun, and you still have a 2.61 overall ratio for high speed cruising. The attached link (borrowed from the TCI website) discusses the pros and cons of tall rear ends. link from TCI website on the 200r4

I still have the 3.90 gear set if I need it but performance aside, will the 3.38 work with the 2004r? The site you linked me to suggested a 3.55 for the guys Chevelle which probably has 2.5x the power my 261 6 does. Thanks

I think the 261 will be straining in overdrive with the 3.38 rear end. As a teenager I had a 52 Chevy with a hopped up 261, a Packard overdrive transmission and a 3.55 pontiac rear end. It would cruise Ok in overdrive on a level but would bogg-down on hills. Now (50 years later) I have 40 Chevy with a mild 302 GMC and a T5 overdrive running a 4.11 rear end. It runs fine -- great pickup and it will cruise all day at 70 without strain.

I would agree with Radar. An automatic, like the 200r4 will be a little more forgiving than a T5, but with a 3.38 in overdrive and 28" (not 281" tires as in my firt response) tires, 70 mph is only 1900 rpm. It will need to downshift too often, at least for my tastes. As TCI points out, cruising at too low low of an RPM can create excess heat.

Thanks for the good advice people. I originally changed to a 3.38 when I was building the truck so I could drive on the hiway with my sm420. I'm really not thrilled with that trans and while I was in to change a rear main seal/oily clutch I figured I'd see about options. I'll go ahead and put that trans back in and think about it. I like the idea of OD and I guess I could go back to 3.38.