So basically I am considering tracking down a truck Muncie 330 3 spd with the 3.03/1.75/1.1 and slightly deeper reverse for my 70S. A car tail shaft and input bearing retainer would needed along with a Hurst floor shifter. Good gear ratios to work with my planned 3.08 gears. They are supposed to be extremely strong. Here is my thoughts on GM automatics below.
In cars maybe the 4L60E were fine, although my BIL's 95 Z28 died well under 200,000 km. Even with all the upgrades like the 5 pinion planet gear set, they still failed a lot in trucks, I saw a lot of GM Reman stickers, only a few year out. GM had a TSB for years, they still have, last I checked. GM has a pretty affordable replacement because of it. I got lucky when my 94 Z71 GM reman trans got the weak reverse. To be fair it towed my Inlaws cattle trailer with no auxiliary cooler and probably had quite a few miles. The fluid was not great when I changed it. The replacement was a $500 wrecker replacement that was rebuilt shortly before the truck was wrote off. It shifted great till the truck burnt to the ground. I also cooked the 3/4 clutch pack towing a light trailer with the 5.3 work truck. I think like the 2004R, I would trust a 700R4/4L60E to only specific builders who have a good reputation for building them. Our local trans shop did one behind a stock 6L truck, made it just over the year warranty, as an example. I have 2004R in the 70S, probably won't live a long life, the usual. I haven't had great luck with the TH350 either, weak reverse and total death behind 165HP of raw Olds 350 power. I threw a Transgo shift kit in one that was behind an Olds 403. Fair bit of clutch material in the pan and some on the magnet. It was shifting pretty lazy, see how long it lives with the shift kit, if I have to use it.
In cars maybe the 4L60E were fine, although my BIL's 95 Z28 died well under 200,000 km. Even with all the upgrades like the 5 pinion planet gear set, they still failed a lot in trucks, I saw a lot of GM Reman stickers, only a few year out. GM had a TSB for years, they still have, last I checked. GM has a pretty affordable replacement because of it. I got lucky when my 94 Z71 GM reman trans got the weak reverse. To be fair it towed my Inlaws cattle trailer with no auxiliary cooler and probably had quite a few miles. The fluid was not great when I changed it. The replacement was a $500 wrecker replacement that was rebuilt shortly before the truck was wrote off. It shifted great till the truck burnt to the ground. I also cooked the 3/4 clutch pack towing a light trailer with the 5.3 work truck. I think like the 2004R, I would trust a 700R4/4L60E to only specific builders who have a good reputation for building them. Our local trans shop did one behind a stock 6L truck, made it just over the year warranty, as an example. I have 2004R in the 70S, probably won't live a long life, the usual. I haven't had great luck with the TH350 either, weak reverse and total death behind 165HP of raw Olds 350 power. I threw a Transgo shift kit in one that was behind an Olds 403. Fair bit of clutch material in the pan and some on the magnet. It was shifting pretty lazy, see how long it lives with the shift kit, if I have to use it.
