Blake Clark

Ok fellas, spent some time under my truck today, took a good look at the speedo set up. Its where I was told, rear of tcase attachs with what looks like a 1 inch nut. There is no physical cable going to it, it has a plug with a couple of wires that run back up to the main wiring harness. Im gonna take a GPS out tomorrow and get an accurate speed difference.

Couple of questions. the speedo gear, I assume that it is accesable once you take the speed sensor off. Looked like a plug in the tcase but wasnt sure if anything was in there. Also, do I have to replace this gear or would a simple reducer/adapter work. Thanks in advance for all the help.

Rick 12v CTD

sorry I didn't take those pictures I've been really busy just trying to get the truck on the road again.
Get an accurate readin of how much your speedo is out by and just order a an adapter to speed up the speedo. It's the easiest way as far as I know. I bought one from PATC
http://www.transmissioncenter.net/sp...n_______va.htm

What your looking for is about 1/5th of the way down the page listed under "GM / Dodge/ Ford Ratio Adapter". For me that's the cheapest place I could find one. If you're looking to speed up the speedo you'll need the #54RA2. When you find out how much you need to speed the speedo up, call them and tell them you need the #54RA2 with XX%. Once you get it you'll be set. I was impressed with their product. The whole thing is metal including the gears and you can take it apart too. The OEM one is all plastic and you have no access to the internal components and it costs twice as much... If you need a custom % it costs $10 extra. Still not bad considering how much the dealership wants for theirs...

Rick 12v CTD

Oh and yes you have access to the drive gear once you remove the VSS. Like I said before, the drive gear is a 15/16" nut. There isn't really any need to take it out unless you want to just so you know what you're looking at. The drive gears are also on the PATC site I linked for ya. It's about half way down the page.

Blake Clark

Okie dokie, Finally got my tires on my truck and the gps out and took it for a spin... When Im marking 45 mph the gps was reading 63 mph. Thats 71 percent. Now if Im thinking along the right lines the adapter wouldnt be to speed it up 71 percent, but to speed it up 29 percent to make it 100 (or close) percent accurate. Final input please before I go ahead and order. Thanks all for the help with this, I really appreciate it.

wannadiesel

71% would make it read way too fast. You wouldn't get many tickets, though.

You want to speed it up 40%.

Blake Clark

Yes Sir, Figured that 71 percent was just completely wrong, but I figured it would be 29 percent, if you dont mind me asking, how did you figure 40 percent. TIA, gonna order here shortly.

rollie

I just did this. Take numerous readings 20 mph, 30 etc all the way to 60, then call Kerry at PATC and he will set you up. I had to change my pinion gear from a 16 to a 15 (no 16 's avail) and it was a 28% decrease. The people at PATC were great I cannot give them enough praise. Cost of the reducer $78.00 with shipping.

Mark Nixon

Number 41 and 42 in the link above is IDENTICAL in appearance to the ones offered for the Getrag transmissions, certainly looks the same as mine.

Hey, an FYI for y'all, these were also used on some early-mid'90s 1 ton and 3/4 ton Dodge vans with 3.9 or 4.10 ratio rear ends, found 2 this way in the past.

Mark.