T-5 5-speed Speedo Adapter and AWD 4L60E VSS- Same Size?

[Casey]

Is the speedo adapter housing from an Astro T-5 (the part which bolts into the trans tailhousing and holds the speedo drive gear for a cable driven speedo) the same size/diamter as the VSS on and AWD Astro?

I'm going from a 4L60E to a T-5, so I'd like to avoid buying a cable-to-electric speedo drive conversion box. Paging through the Advance Auto 'site it appears the AWD Astro VSS is much smaller in diameter than the 4L60E's VSS which I currently have, so I'm curious if the AWD VSS is a direct bolt in to a cable driven trans case. I'm not concerned about the reluctor ring on the tailshaft at this point, just the physical size of the holes in the trans/transfer case. I don't really want to plunk down $55 just to measure the AWD VSS's diameter and I don't have the T-5 trans yet, so I'm just trying to think/measure ahead.

The AWD ('95 in this case) VSS is shown in the attached pics.

[Casey]

I did more research and found two VSS diameters- 54mm and 22mm. I believe the T-5 uses the 22mm VSS, and I've found other GM vehicles use the same size VSS, so I might get lucky.

[doyoulikeithere]

Just Curious, Which T5 are you using?
I have a 1352-164 2wd, and a 1352-043 4wd.
I am contemplating to steal the mainshaft and tailhouse from the 043, in order to modify the -164 to work with a transfer case, and keep the nice "Astro" gearing.
Fortunately, I wont need to adapt the speedo , I can just use the cable set up.

[Casey]

Just Curious, Which T5 are you using?
I have a 1352-164 2wd, and a 1352-043 4wd.
I am contemplating to steal the mainshaft and tailhouse from the 043, in order to modify the -164 to work with a transfer case, and keep the nice "Astro" gearing.
Fortunately, I wont need to adapt the speedo , I can just use the cable set up.

I'm using an '86 -164 T5. I see no reason why your idea wouldn't work.

The VSS is my last hurdle. Mounting the reluctor ring on the output shaft wasn't hard, but finding a VSS I can modify is a bit of a challenge. I'll figure something out.

[astro355]

I'm not sure why you found different sizes but on the 3rd gen Firebirds and Camaros, all of the VSS's regardless if it was for a manual or automatic were the same size diameter. The automatics for those cars is a 700R4.

[Casey]

I'm not sure why you found different sizes but on the 3rd gen Firebirds and Camaros, all of the VSS's regardless if it was for a manual or automatic were the same size diameter. The automatics for those cars is a 700R4.

I've found lots of variation in VSS sizes and styles, from hybrid to fully electric, 2WD to 4WD, and so on. Most of the late model ('93+ using the 4L60E in trucks) VSSs are approx. 15/16" in diameter, so none will fit iside the driven gear tailhousing bore in an Astro T5 tailhousing. With and S-10 tailhousing it's a breeze, but not with the unique Astro piece. Plus there's no ideal place to tap into the tailhousing to mount a threaded VSS in the Astro T5 tailhousing.

My issue is I need a 40,000 pulse/mile signal, and none of the gear driven (hybrid) VSSs can provide more than 17,000ppm. I want the ABS, cruise, and speedo to work properly.

[astro355]

What setup uses the 40,000 ppm?

[Casey]

What setup uses the 40,000 ppm?

'93+ trucks and '94+ cars. 40 pulses/driveshaft revolution x 1,000 revolutions/mile = 40,000 ppm

[astro355]

What year is the T5 you want to use? If you get a newer T5, why will there be an issue? What difference does the diameter make if the connector is the same? I'm missing something here, please help me.

[Casey]

I posted this question before I got my '86 T5, so the original question is a bit outdated at this point.

I have an '86 T-5 out of an Astro which is going in my '95 Astro, and the bore in the T-5 tailhousing (TH from now on) into which the sleeve fits (the sleeve holds the driven gear, which in turn drives the speedo cable) measures about 7/8". I need to replace the speedo cable drive setup with a VSS, so I was hoping to fond a VSS which had the same O.D. as the TH bore's I.D., but the closest VSS I found has an O.D. of just under 15/16", so it doesn't quite fit in the bore.

Hopefully that clears up what I'm doing for now. I'll post some pics when I'm finished.

[astro355]

Yes, thank you. Now I get it. The T5 being older is what was throwing me off. Any chance you could find a newer T5? Or if the tailshafts are comparable from the 86 T5 to the 95ish T5, maybe just swap them?

[Casey]

Yes, thank you. Now I get it. The T5 being older is what was throwing me off. Any chance you could find a newer T5? Or if the tailshafts are comparable from the 86 T5 to the 95ish T5, maybe just swap them?

I wish. Since the Astro tailhousing casting is unique to Astro/Safaris, that's the only choice to retain the proper shifter mount position. The S-10 shifter mount is at the very front of the TH casting, while most of the car (Camaro/Mustang/280ZX) mounts are at the rear of the TH case. If I was desperate I could use and S-10 TH and create an offset shifter stick to allow it to poke through the Astro's floorpan in the porper location, but the top of the offset shifter mechanism passes through the floorpan and into the cab area slightly, so that really wouldn't work either.

I made the '98 Blazer sensor fit and have it installed, so when I get the new clutch M/C installed I'll be able to test it all out and see if it works.

[Casey]

Well, I finally got the new clutch master cylinder installed and the line bled, and the clutch works great. I shifted the trans through all five forward gears and reverse while the van was still on jackstands and it shifted great, so I dropped it back on all four tires and took it for a test drive.

Unfortunately, the VSS setup I made isn't working, so I'll have to go back to the drawing board. I figured that would be the #1 problem, and that is in fact the case. Because the VSS isn't sending a signal the ABS, cruise and speedo aren't working, but I can deal with that until I get the VSS figured out.

I did notice the engine idle dropped a bit too low (as expected) as I depressed the clutch and came to my second stop, but after that it seemed to be ok. I'm not sure that the PCM can re-learn where the correct engine idle rpm should be (the battery was disconnected for a few days) now that the 4L60E is gone, but I'll get a better idea of how the idle speed is reacting once I drive it a bit more. I was low on gas and only did a two-mile test loop with three stops, but did go through all gears at speed and it sure feels good to shift it myself!