GreenieG

i got a 85 iroc that i wanna swap the t5 out for a t56, i've done alot of reading on it but im still stumped on how to get my speedometer to work with the t56? i wanna keep the stock gauges. what exactly do i need to achieve this? thanks for any help.

sofakingdom

iTrader: (1)

Best way is to have the extension housing modified to accept a speedo gear. Then all you gotta do, is put your T-5 gears into it.

Be forewarned though, the mod is NOT trivial; not something you can do yourself unless you have a fairly well-equipped machine shop and know what you're doing before you start.

I don't know what gears you have in your car's rear, of course; but you'll probably find that they're WAY too low. The T-56 will want at least a 3.42, and preferably 3.73 or even 4.10. Otherwise taking off from a stop will feel about like it's in 2nd in your T-5, and you'll NEVER be able to use 5th gear. Try that a few times before you swap so you'll be prepared for what's coming.

There used to be a member on here that did that mod. IIRC his userid was Alloy. No idea how much he charges or if he still does it. Given what's involved though, it won't be cheeeeeep; expect the cost to be something in the $200 - 300 kind of range, and that you'll need to send him your ext hsg and wait for it to get done. (JTR used to be the same way and cost about the same, but AFAIK stopped doing it years ago)

GreenieG

i have 3.73 in the rear. so there isnt a conversion kit or something i could get thats less intense?

jmd

iTrader: (4)

3.73 is the minimum so that'll be fine.

$300 isn't intense.
His mod leaves the stock VSS setup in place. So if you later go to a later model engine, the VSS still works for that.

InfernalVortex

iTrader: (4)

Can you get a gauge cluster from an 89 and use an 89 VSS? Or is the 89 still an analog speedo?

sofakingdom

iTrader: (1)

Nope, can't use a 89 VSS.

In all of the 3rd gen transmissions, the VSS (the trans-mounted ones anyway) are offset from the center of the mainshaft, such that a speedo gear can ride next to it.

In the T-56, the hole for the VSS is pointed RIGHT STRAIGHT AT the mainshaft; and the mainshaft has a reluctor on it with IIRC 17 teeth. So even if you used a T-56 VSS you'd still be getting 8½ times as many pulses as the 3rd gen system wants. (will think it's going 8½ times as fast as it really is)

You could overcome that with the Dakota Digital divider, or the like; but by the time you do that, you'd have around $200 in it. PLUS, then you'd have to get some other dash, wire it all up and get it to work, etc. etc. etc. etc. Probably about the same $$$ by the time you were done, but ALL KINDS of extra WORK, and RISK. 2 of the ugliest 4-letter words ending with the letter K, in my vocabulary.

What I described earlier IS the "conversion kit". Frankly that doesn't seem particularly "intense" to me, either. People waste more than that on .... all sorts of useless things for their cars, not least of which, is "appearance" related trifles. Doesn't seem out of line at all for something that actually ACCOMPLISHES something USEFUL.

Wanna play, ya gotta pay. No way around it. Either ya wanna, or ya don't. Make up yer mind.

zenish

no buck method...download a speedometer app for your phone and mount it in a bracket in your car.they work pretty well and are free.i'll admit,*******.

InfernalVortex

iTrader: (4)

Is an 89 Dash that expensive that an $80 convertor box makes it financially impractical compared to the $200+ Analog->Digital Converter box? And to be clear, that's exactly what Iw as insinuating. Convert it to an electronic speedo to just use the cheap electric converter box.

Did any of the other gauges change significantly by that point? Or is it only the speedo?

jmd

iTrader: (4)

A 90 gauge cluster doesn't fit an 89-down dash.
Wiring changes aren't that bad.

Gauges should be the same resistance.

Removing a T56 tailhousing is EASY and so is setting the countershaft extension bearing endplay while you're in there.

Need cable drive? Modify the tailhousing.

Got a modified tailhousing? You can run a third gen VSS. Or 4th gen style. Or cable and 4th gen style.

No longer run cable drive but are keeping the transmission? Swap an unmodified one on and sell the modified one.

Yes, it's all simpler and less intense than
Replace the whole effing dash
rewiring stuff and adding a buffer device.

GreenieG

okay yeah it does seem easier to go with the conversion so thats what ill probably do. thanks for the info guys.

naf

iTrader: (7)

I have seen some discussion of using the firebird speedo with the converter box. Firebirds went to electric speedo in 86 and the gauge 'should' (I haven't tried it) swap into the Camaro cluster. Should even be able to swap guage faces (the Firebird speedo has a different background pattern).

85Z28NOS

iTrader: (2)

http://www.jagsthatrun.com/Pages/Spe...eedometer.html
or
http://www.jagsthatrun.com/Pages/Par...pp6-3_6-4.html

jmd

iTrader: (4)

You're just being optimistic.

I've seen the bird speedo swapped into other GM clusters, but there are plenty of other OEM speedos that accept the same 4004ppm signal.

alloy

iTrader: (16)

Jags that run hasn't done the conversions for years now. I wish they would pull that page down.

GreenieG: If you need the tail housing conversion done PM me. I"ve been doing them since 2008.

Read about what my customers think of the service I give them from the link below.

https://www.thirdgen.org/forums/clas...xcellence.html

www.t56cablespeedometer.com

tom86iroc

iTrader: (1)

I used this and had a small speedo cable made since i mounted the box under my pass. seat it like 340 now it went up but it's another option http://www.abbott-tach.com/cablex.htm

irocdis

Yup ALLOY....(DAN) Solid Guy, excellent service, no issues, only catch you have to ship your tail housing to Vancouver, WA.

t56cablespeedometer@yahoo.com

absaraka

I will be contacting you in the next week regarding my T-56 build.