Not really slant six related, I know, but what year(s) was it that chrysler was having all the problems w/ the 4 spd autos? I'm looking at potentially picking up a very nice '93 Ram, but it's got the OD tranny and I'm a little leary.

All 518 and a500 trans will eventually wear out. The problem with 4spd auto is mostly the a604 in the (fwd)vans. The truck trans is basically old torqueflite with a plantary reduction overdrive onthe end of the case. I think that for 93 they were still using non computer controlled lockup on the trucks but I could be mistaken.

Mcnoople's right that the FWD/AWD 4-speed automatics, based on the 1989 A604 "UltraDrive" (ProbleMaticâ„¢) are far worse than the RWD truck transmissions. Still, the A500/A518 RWD units aren't nearly as bulletproof as the A904 and A727 upon which they were based. Any trans man worth his salt will be able to list off the problem areas and their respective preventive fixes. One I know offhand is that the rear bearing (in the O/D, if I'm not mistaken) tends to suffer from inadequate fluid feed, starving it for lubrication and failing it expensively. Don't assume you're good to go just because it's not an A604-based transmission; Chrysler pissed away their well-earned reputation for the industry's best automatics with the A604, but they flushed it with the "adequate but not superior" A500/A518.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

A 93 A500 or A518 would be a good swap behind a Slant with the adapter plate - right, no complex electronic controls, just 2 solenoids.

I believe some simple mods to the valve body that firm up shifting should keep those trannys alive. I don't know the limits on the A500 yet, but I will test them eventually on my 68...

Lou

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Home of Slant6-powered fun machines since 1988

The problems were with the front-drive minivan 4-speeds (A-604/41TE), not the rear-drive A-500 and A-518. Early (pre-92, I think) versions of the A-500 and A-518 did have a weaker overdrive unit than the later ones, but it still wasn't a raging problem like the FWD trannies had.

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Another thought:

After having now seen both installations in person and not just in print, I have to say that a Gear Vendors Overdrive bolted onto an original A-727 is a MUCH nicer installation than shoehorning an A-518 or A-500 in. Especially if said A-727 is behind a slant-6 or a big-block, since an A-500/A518 will only go behind a smallblock v8 without an adaptor plate. The GVO unit doesn't even require a lot of floor pan welding (in a B-body, it only requires a little massaging with a body hammer, probably no work at all in a C-body, maybe no welding in an A-body). Plus it needs no changes to the crossmember. An A-518 requires floorpan mods, a revised rear mount, and crossmember modifications on A, B, and C-bodies. The one thing that the GVO needs that the others don't is a shortened driveshaft. But that's cheap, reversible, and easy compared to the floor and crossmember mods.

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