Transmission Swap

[profaqualung]

Has anyone out there replaced the Stude transmission that originally came in their Avanti II, with a GM unit - specifically a 200R4 ?

If so, what was involved in hooking up the factory speedometer to the GM transmission ?

I know Gunslinger is using an after market speedo in his 70 Avanti II, but if at all possible, I would like to keep all the gauges original.

All suggestions will be appreciated.

[WayneC]

All suggestions will be appreciated.

I don't see it as a serious problem, it should be just a matter of finding the correct length speedo cable and using

the right plastic driven speedo gear in the transmission, which is easily changed, it simply slides in/out.

After all, 70's Avanti II's came with a GM tranny and use a mechanically-driven speedo cable

and they work fine... question is whether the internal "gearing" of your speedo is the same as those later

Avanti II's, and I can't answer that, though I suspect it is. If you could get your hands on a later speedo you

could hook it up to your current cable and see if it matches your current mph reading at a specific rpm in high gear

(or vice-versa, connect your speedo in a car with a 200R4).

Worst case, perhaps you could get a newer speedo, disassemble it, and put your old speedo face in the newer speedo

(or farm that work out to a repair shop).

This listing might help: http://www.montess.org/speedo_gears.html

But that requires knowing which drive gear your 200R4 currently has, and that will be a function of the number of teeth on it...

perhaps a tranny shop could answer that, or if you know what car it came from, perhaps a Chevy parts dealer can look up

the part number.

There also are variable-speed adjustable adapter boxes that can be mounted inline somewhere on the

speedo cable route, but they are pretty expensive and comparatively bulky.

Edited November 7, 2008 by WayneC

[Gunslinger]

After all, 70's Avanti II's came with a GM tranny and use a mechanically-driven speedo cable

and they work fine...

Wayne...

FYI...Avanti II's came with the Borg Warner automatic until either late in the '70 model year or sometime in the '71 model year. My '70, a September 1970 build car, came with the B-W, as did Profaqualung's, which is an earlier '70 RQA model (mine is an RQB).

[WayneC]

Wayne...

FYI...Avanti II's came with the Borg Warner automatic until either late in the '70 model year or sometime in the '71 model year. My '70, a September 1970 build car, came with the B-W, as did Profaqualung's, which is an earlier '70 RQA model (mine is an RQB).

I understand that... I once owned a '66, and a '69 with BW's... I've also owned a '63, '71, '80, and '89 over the past 35 years.

My point was that the later cars had a GM tranny with a mechanical cable to their speedo, as did the Borg Warner Avanti's,

so barring some gear issue within the speedo, replacing a Borg Warner with a 200R4 should only require finding a suitable

cable and the proper tranny driven speedo gear to match his differential and tire size.

But I have not done a tranny swap, so maybe I misunderstood his question?

Edited November 8, 2008 by WayneC

[profaqualung]

THANKS GUYS - I SEEM TO HAVE MADE A MOUNTAIN OUT OF A MOLE HILL.

TURNS OUT THAT THERE ARE ANY NUMBER OF PLACES WHO CAN TAKE THE OLD CABLE, AND PUT A NEW END TO FIT IN THE 200R4 - THEN IT JUST BECOMES A MATTER OF SELCTING THE CORRECT PLASTIC GEAR TO FIT ON THAT END. THE HARD PART BEING THE REMOVAL OF THE OLD CABLE, AND THEN REINSTALLING IT WHEN IT COMES BACK.

IN CASE ANY ONE ELSE RUNS INTO THIS PROBLEM, HERE ARE SOME OTHERS THAT WILL FIX THE PROBLEM

SPEEDO SERVICE - PORTLAND, OREGON - 1-800-6342145 - SUGGESTED BY STEWART WARNER

BLOOMENTHAL TRANS - OKC, OK [GO SOONERS] - 1-800-2629557

AND THE LISTING WAYNE SUGGESTED - THEY HAD AN E-MAIL WAITING FOR ME FIRST THING THIS MORNING.

WOULDN'T IT BE NICE IF ALL PROBLEMS WERE THIS EASY TO FIND A CURE FOR ? ? ?

THOMAS