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f.monroe · 12-18-2006, 11:23 PM

I have been driving my 87 3/4 ton a lot lately . It has a factory 4.10 posi rear axle and the little 350 is wound pretty tight at highway speed . (My 05 work truck has a 4.10 rear and turns about 3300 in drive and 2500 in OD . I figure the final drive is around 3.0x with the OD . )I thought of an overdrive 4L80 but have been thinking 3.42 gears would help and is a lot cheaper . I think the 3.42's would still allow it to pull and with the 33x12.50x16.5's would offer a little releif on the highway . What do you think ? 3.42's or a 4L80 ? Also , has anyone here installed a 4L80 in one of these trucks and did you have any problems ? Frank

12-18-2006, 11:23 PM	#1
f.monroe Senior Member Join Date: May 2004 Location: Caldwell,Tx. Posts: 3,648	Overdrive or Gears I have been driving my 87 3/4 ton a lot lately . It has a factory 4.10 posi rear axle and the little 350 is wound pretty tight at highway speed . (My 05 work truck has a 4.10 rear and turns about 3300 in drive and 2500 in OD . I figure the final drive is around 3.0x with the OD . )I thought of an overdrive 4L80 but have been thinking 3.42 gears would help and is a lot cheaper . I think the 3.42's would still allow it to pull and with the 33x12.50x16.5's would offer a little releif on the highway . What do you think ? 3.42's or a 4L80 ? Also , has anyone here installed a 4L80 in one of these trucks and did you have any problems ? Frank __________________ Born and proudly residing in a Red State !