Originally Posted By: 440Magnum
Originally Posted By: NHHEMI
Originally Posted By: 440Magnum
I do miss the days when the old 727s and 904s had convertor drain plugs and you could easily change 100% of the fluid- the irony being that those transmissions were so overbuilt that they rarely ever *needed* a fluid change...
Preach on Brother. Preach on!
WHY auto mfg's in general no longer have the TC drain plugs is beyond me?
I gather that when Chrysler was scrambling to get their first lockup TC design in place (remember this was circa 1976, one of those not so good eras for Chrysler financially) that the lockup clutch material was located right where the drain plug would have to pass through it. So the drain plug was deleted rather than coming up with a fundamentally different convertor housing, which would have had a lot of ripple-down changes.
Now why OTHER companies lost the drain plug, and why Chrysler didn't put it back in later years, like the early 90s when they were swimming in money, remains a mystery to me. Being a bit of a cynic, I think it has to do with making things appear to be "sealed for life" which appeals to a lot of buyers out there. Same as with Toyota and Chrysler removing dipsticks from their automatics now
As for 904 vs 727- have you ever opened both up? The 904 is for all intents and purposes just a scale-model of the 727. They even can swap valve bodies and a few other parts. The 904 has lighter gears and lighter/smaller clutch packs so its got significantly less parasitic power loss. In stock form, I wouldn't put it behind anything bigger than a 318, but with some modifications, it can handle a lot. The later "A998" and "A999" versions of the 904 had a deeper first gear ratio and extra clutch plates for truck and copcar use. For a while, drag racers liked to put built 904s behind big blocks and hemis (even though adaptors are required- no 904 was ever made with the big-block bolt pattern) because they lost less power in the transmission than with a 727. Of course they weren't going for longevity, either... I'll keep my 727s!
Yes, I have seen both tranny's in pieces and yes they are similar. I have never rebuilt a tranny personally but watched it done. I have the distinction however of being a 904 killer of the highest degree. Even behind a mildly modified 318 the 904 dies pretty easy in "stock form". TRUST ME!
I did mention they can be built to take abuse but that costs a lot more than buying a used 727 from a small block powered cruiser and just freshening it up and throwing it in. Well, it did back when I was into that stuff with cars. These days I imagine a 727 out of a small block cruiser is getting scarce as an honest Politician and would bring a premium price tag even if blown up. Might be cheaper these days to build a 904?
I would love to be able to adapt a 727 w/ an aftermarket overdrive to my HEMI Ram. NOTHING shifts like a 727. My last Road Runner was a Volare version with a 300+ HP 318. I killed the original 904 I had freshened up( B&M rebuild kit they used selective parts out of, added a shift kit, and synthetic fluid )in about 2 weeks. I got a 727 from a 360 powered Crusier and added a shift kit and some synthetic fluid( was in GREAT shape - came out of a 40K totalled cruiser ). LOVED IT!
The 727 was one of the best auto tranny's ever built along with the GM TH400( Ford C6 was OK but not as good, IMO as the other two ).