Jump to content

Speed Sensor Buffer DRAC

Joe Fortenberry
 Share

Recommended Posts

Mikebtte Enthusiast

Mikebtte

Posted
Posted

You most likely have a 700R4/4L60 and not a 4L60E. 4L60E had the DRAC and you would swap it for a Box with DIP switches or add them yourself. 

4L60E was not used until 93. You have a TV Cable and will need to approach a little different in fixing your issue.

Mikebtte Enthusiast

Mikebtte

Posted
Posted (edited)

TV cable runs to the throttle body and controls pressure in the transmission for shift points. Should be adjusted using a pressure gauge.

You should have a cable coming off the transmission going to the speedometer for speed.

The DRAC was used as a buffer box to send a digital signal received from the transmission to the ECM/cruise and the dash on new year model trucks.

88 had no DRAC but 89 did. If you received and early 89 its possible to have one. It will look like one of the many combinations below. In the Vans it was behind the dash on the drivers side, on the trucks it was behind the glove box.

Warrperformance offers units with a DIP switch installed if needed. Also a usefull source of information on the units.

 

https://warrperformance.com/?product=modified-gm-drac-to-adjust-for-different-tires-gear-ratios-tbi

 

DRAC.jpg

Edited by Mikebtte
Joe Fortenberry New Member

Joe Fortenberry

Posted
  • Author
Posted

I do not have a cable coming off the transmission going to the speedometer nor can we find a DRAC. However one of my mechanic friends even gave me one for possible use. It is definitely not under the glovebox or anywhere under the dash.  That's why we're so befuddled. 

Mikebtte Enthusiast

Mikebtte

Posted
Posted (edited)

That makes since as the 88 had no DRAC, I think you are good on that point. Forgive me as it has been a while, You should have a 2 wire sensor putting out a magnetic pulse the the speedo and a TV cable at the throttle body.

 

1913175329_TVCable.jpg.b35d9c84b3e406d6f223e83eaf6d3c56.jpg

 

Edited by Mikebtte
riverbanks Senior Enthusiast

riverbanks

Posted
Posted

Yup,educated me too,been a while also,can't explain my post,cause I didn't see the drac,I assumed it was not on 2 wd ,found more good info on udmodule.com

  • 3 years later...
  • 5 months later...
CouchRider New Member

CouchRider

Posted
Posted

I have a 97 Tahoe &speedometer is 10 mph fast wheel and tire are factory size and I’ve already changed the VSS  in transmission..

What can I do next to correct this problem?  97  Tahoe 4x4  5.7 Vortec I’m getting doesn’t have drac. 
Does anybody know if it has one or not and where it is . Or what else could be causing my speedometer to be 10 mph fast.

  • 4 months later...
Austin s New Member

Austin s

Posted
Posted

This issue ever get solved? I have the same issue with a 1997 GMC Sanoma 4.3l 4L60E. Speedometer is off by 10 MPH at 70 and after driving a while it causes the trans to shift hard and code for p1870 which is a general trans component slippage because the truck isn’t moving as fast as it the computer thinks it is. Could this be a PCM issue or is there a DRAC box?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.6k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    343,007
    Total Members
    8,960
    Most Online
    Brendan C
    Newest Member
    Brendan C
    Joined

  • Who's Online   2 Members, 0 Anonymous, 1,117 Guests (See full list)

  • Latest Articles

  • Posts

    • Z45
      2026 6.6 L5P oil cooler leaking oil at 4,000 miles

      By Z45 · Posted

      The oil filter has NOTHING To do with oil leak. GM sources parts from 1,000's of vendors and as with anything mass produced, flaws are unavoidable.    Putting a larger oil filter will do nothing but satisfy emotions. The OEM filter is designed for the engine and perfectly capable of handling the demands on the engine. Oversize oil filter could result in reduced flow and overall lower oil pressure.
    • Grumpy Bear
      Joke Thread

      By Grumpy Bear · Posted

    • Grumpy Bear
      The Peckish Synapse

      By Grumpy Bear · Posted

      You're better read than that Atlas. 😏   British science fiction writer Arthur C. Clarke formulated three adages that are known as Clarke's three laws, of which the third law – that "any sufficiently advanced technology is indistinguishable from magic" – is the best known and most widely cited.   Stribeck and the pivotable Hersey Number isn't voodoo nor snake oil. That part is physics. It's what marketing and bean counters do with it that is snake oil and voodoo.    Stribeck is the relationship between Hersey and the Coefficient of Friction. Within the Hersey Equation if viscosity and viscosity is 'Dependent' on.......heat.......and.......viscosity index or the temperature to viscosity slope.    Specifically Hersey is the viscosity AT THE TEMPERATURE IN THAT LOCATION FOR THAT SLOPE.   Hydrodynamic lubrication exist when the film thickness in the location is 3X the Ra roughness of the surface. This is irrespective of the hardness of the substrate. To obtain that thickness X viscosity is required for Y velocity at Z load. That's a lot of moving parts. It is also impossible to maintain in an ICE but nearly possible with a turbine under constant load.    What does that mean? Error heavy and operate light. Wear is inevitable but the rate of wear and the milage obtainable are a function of prevailing conditions and HABITS. The only penalty is viscous drag and at fractions so low as to be well worth the effort. Double the life, half the manufacturing carbon foot print. Greed is the only impediment.    The materials generated by SwRI are the RESULT not an estimation or a hypothesis.    Don't delude yourself sir, EV's have as many pitfalls as ICE's. We just don't know what they are yet and it will take longer to sort as MARKETING and GREEDY CEO's have had more time to polish the turd they are selling. 
    • Grumpy Bear
      The Peckish Synapse

      By Grumpy Bear · Posted

      You can always count on greed to prey on ignorance and stupidity.    Friend bought a 2019 Ford Flex and asked me about using Valvoline R&P 5W30 in it. Told him give the miles on it and the fact it wasn't yet using oil that it was a good plan. He uses a Valvoline quick change shop for his oil service.   First they tell him that isn't the oil the OEM recommends. He told them he didn't care what the OEM thought. Then they floated the, "But it will void your warranty"    His reply was it's a 2019, there is no warranty and informed them their knowledge of the law was lacking.    Then they tell him 'But it will ruin your motor"!.    Mine to ruin he says. Finally they give in and charge him 150% the semi-syn price    Point it the brainwash is so embedded that even the service industry is drunk on their swill. The public is right behind them. Echoing the same lies on every forum and media platform. If the end goal is indeed EV then I'd say that ship is about built. 
    • CamGTP
      Gas Prices

      By CamGTP · Posted

      Diesel hit $6.00 here today at the truck stop.   Payed $2.79 for E85 today too.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...