62 Starfire transmission

[Guest]

Anyone know the correct shift points for my 62 Starfire. Which gear should I be using for normal driving around town? When driving in the last gear (Highest on selector, numbers gone) it shifts from 1st to 3rd or 4th (not sure which). If I manually row thorugh the gears, they all work fine. I'm not familiar with these trans so any help would be greatly appreciated!

[Sgt Art]

Would that be the infamous "Slim Jim" tranny? I remember my buddy in high school had an early 60's 98 with a Slim Jim. It failed and it cost a bunch to repair. But I seem to recall it was only a three speed with "D" "S" (was that a marketing ploy?) and "1".

[rocketraider]

Unfortunately, it's working about like it's supposed to. I've seen very few SlimJims that didn't feel like they were skipping a gear between 1st and 2nd. I've got one in a 64 Starfire that feels like the engine's gonna stall when it shifts. It is officially a 3-speed unit, but every manual except 1961 refers to it as "4-S HydraMatic". It's a weird transmission, and was revised every year it was produced (1961-64), sometimes 2 or 3 times in one model year. Every year had different gear ratios and often different shift characteristics.

I recommend buying a 1962 Olds factory service manual and a set of 1962 Service Guild/Tech Bulletins. Also a parts requisition booklet for 1961-64 HydraMatic. These will show revisions and operation of the Roto-HydraMatic 375 Model 10.

So don't think it's acting up. It's probably working right! <img src="http://www.aaca.org/ubbthreads/images/graemlins/shocked.gif" alt="" /> <img src="http://www.aaca.org/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="http://www.aaca.org/ubbthreads/images/graemlins/crazy.gif" alt="" />

[Sgt Art]

How hard would it be to replace it with a TH350 or someother more reliable tranny? I've heard the Slim Jims were really dogs. Even back when I was a teenager we heard they were bad news.

[Guest]

Thanks for the info! I'm glad someone else is experiencing the "weirdness" of this tranny. Which gear do you normally use around town versus freeway cruising, or do you stay in one?

[rocketraider]

I just leave it in drive for all conditions. I have an original Hurst Dual/Gate shifter for SlimJim but don't know if I'll ever install it. That tells me the things had some performance potential. The one in the green Starfire works great, the blue one does the hucklebuck.

It's possible the TV rod from carb to tranny could be out of adjustment causing the weird shifts, but these things are a different animal.

The way Olds made their engine blocks, a Turbo HydraMatic case has to be modified to fit a 394 (or earlier) block. Couple of companies are doing it, and it's not cheap. Sometimes I think it would be worth it to get rid of the SlimJim/4GC combo <img src="http://www.aaca.org/ubbthreads/images/graemlins/tongue.gif" alt="" />.

Pontiac had the right idea on bolting them to the engine. SlimJims need a bellhousing to adapt to a Pontiac block. And that bellhousing just happens to be the same bolt pattern as a 1965-later Turbo HydraMatic. So the Pontiac guys have it made when their SlimJim quits. They can put a modern tranny in with no issues except driveshaft length and crossmember location.

Booey.