Jeremy Cusick

The '95 1 ton I just bought had a gearvendors OD unit in it, but the guy I bought it from had it removed so he could install it in his new truck. My problem is that the speedo reads 10 mph faster than my actuall speed. Is there and easy fix to this, or do I need to change the speedo gear in the tailshaft housing? Any idea what gear I'd need? I think I have 3.54 gears... it runs about 2100RPM at 70MPH ( if I remember right... I may recheck that statement after bit).
I'd appreciate any help I can get.

linetrash75

my 3.54 equipped truck runs 2250rpms @75, 2125@70, and 2000@65mph. sounds as if your speedo is correct if you have factory sized tires.

jed

Fat Framer

the gear vendor does not alter the speedometer gear, it adds an entension to the speedo cable and then reads off the output side of the gearvendor which spins the same speed as the driveshaft.

Jeremy Cusick

THat was corrected speed. It shows 80 MPH at 2100 or so. Dad was following me home in mom's car, and told me what speed I was running at. I didn't know if maybe the gear vendors unit needed a different gear or not. I'm wondering if maybe when they took it out they put the wrong speedo gear in the tailshaft housing.
The tires are stock size, so that's not it. I'm thinking of going to the dealer and asking for a new drive gear for my truck. That is unless there's something outside the transmission I could change. Is there an adjustment I could make to the thing the cable hooks to that has 2 wires that (I assume) go to the speedo?

j-fox

I believe the 95 used a gear for the speedo calibration.
You can go to a dealer and get it corrected.
Do you know what gear is in it?
BTW, to find it, remove the cable then the gear holder assm, and count or read the number cast into it.
A general rule is 1 tooth will change the speedo by 2-3 mph at 60.
If it is reading high by 10 at 70 you need 3 more teeth.

Jeremy Cusick

So I can change this gear without pulling the output shaft housing? That's a relief! I'LL run by the local dealer and see if they can help me out. They should know what gear is supposed to be in it from the factory. I looked at the spec tag under the hood... says it has a 3.5 gear and limited slip dif.

Smokee

THe shop manual has a listing of the different gears. Make sure that you look at the manual to get the orientation of the gear ans housing correct.

Jeremy Cusick

I have no shop manual. :-( How much does dodge charge for one? Is the one on CD cheaper?

Jeremy Cusick

Went to the dodge dealer today. They were very helpful, but their computer shows 2 different gears for my truck (31 and 32 tooth). He suggested that I pull mine and count the teeth. My question is: Is this thing gonna dump oil when I pull the speedo gear housing from the tailshaft?

Jeremy Cusick

I went and pulled it... it has a 27 tooth gear, and the parts man says it's supposed to have a 31 or 32 tooth, so therein lies the problem.
I also found that I have a throttle return spring missing, along with a small bracket that it hooks to, so I'm going back to order some more parts tomorrow.

Then it's a trip to cummins for some parts and filters.