I swapped a 4th gen rear with 4.10s in my 91 Z28 TPI, with a 87 T-5WC transmission.

Now the speed shows 70 at 55, so I called around to transmission shops, and one of the guys told me I need to change something in the PROM. So I searched for it, but I couldnt find any information.

Do I need a new speed-o gear, to change a table in tunercar, or get a dakota digital box?

 

Need to change the gear(s) in the transmission.

RBob.

 

gears yes.

I'm trying to find the right gear for ya for a VSS; I found the one for a cable speedo.

 

jmd--Do you have a site that will tell me what speedo gears to run with a T5, 3.23's and a cable speedometer? I found the one for 700R4--it said a 19 tooth. Would that be the same for a T5?

 

700 has different drive and driven gears than a T5 so it's totally different. I'll look ya up in a bit here.

 

This seems as good a place as any to ask this,

Do all VSS setups use a gear too? I was under the impression that the VSS in the back of say a 700R4 was a magnetic pickup type deal, like an ABS sensor working on (correct me if I'm wrong) the Hall Effect?

The reason I bring this up is I have an LT1 out of a 93 Cop car w/ the 700R Tranny (I think, now I'm starting to second guess), digital dash, etc in my garage lined up for the next project. I thought you had to either change the calibration in the computer or someone told me there were DIP switches on the back of the speedo head.

Anyway, long story even longer, I popped the VSS out of the tranny when I got it and found no gear.

 

jmd did you find what gear I need? Also a place to buy one? There are no shops locally that have them in stock, so I might as well just buy one and put it in myself.

 

how do you like your 4:10 gears??

 

Steven, give me a shout on AIM. I got just the gear you need. And I'm local.

Lou

 

Lou--Finally got registered on the Austin board--do you have a gear for a T5 with 3.23's? There's a great parts house in my town but I have to know how many teeth I'm looking for.

 

Hmmm, don't you have a cable driven speedometer? I'm not sure if they use the same gears. If so, then it's not a problem to calculate.

Tell me all you know about the tranny, rear end (did you do a swap?), tires, speedometer deviation etc. Every little bit of info helps.

Lou

 

Yup--I took out the automatic and put in a '91 WC T5. It has a dynamite rear end that my brother built with Moser axles and posi 3.73's--but he's a drag racer and I'm a road racer so I'm going to 3.23's.
I'll get you the tire size and all this evening--got to go do some stuff right now--thanks!

 

I have a 90 camaro with a 5speed electronic speedo and a 9 bolt 3.27 originally a 3.08 what gear would i need?

 

Does your speedometer show 6% more now? E.g. 85 when you're going 80?

I don't have the sheet right here with me but I'll get it and post an answer after lunch.

Lou

 

Spdfrk1990, unfortunatelly, there is no gear combination for your application. There are only 2 drive gears and 2 driven gears for the T-5 so that creates only 4 combinations, for 2.73, 3.08, 3.42 and 4.10 gears. You are closer to the 3.08 so I would stay with those gears.

Somebody mentioned the Dakota Digital box, you can try that.

Sorry I couldn't help.
Lou

 

not all.

in the 3rdgens case, they made a VSS sensor that goes in place of the cable connector.

the sensor is turned by replaceable plastic gears to give the rate of 4000 pulses per mile.


in most modern cars, like the 4thgens T56 trans, the VSS wheel is permantly attached to the output shaft, and a regular hall effect sensor is stationary on the side...
this gives X number of pulses per driveshaft revolution.
the PCM calibrates this signal according to whats programmed into it.

so with a 4thgen, you would use a PCM programmer to set your speedo with a gear swap.

with a 3rdgen, you swap the plastic gears in the trans.

with a 3rdgen that has a 4thgen trans, you use a calibration box that multiplys or divides the signal to make it correct.

 

ahhh, my thread was hijacked!

Me and lou took a look at my VSS gears and we found that I need to drop 2 gears on the gear on the tailshaft, red to purple(9 to 7) to get a 'close enough' setting for the 4.10s.

And ramair21, I like the 4.10s alot, but I wouldn't recommend getting them if you drive on the highway alot, unless you have a 6 speed tranny. Put some slicks on and watch the competition in your rearview, hehe :lala: