93 D350 Speedo Query
 

Having a hard time getting the right parts to repair my speedo.
I have replaced the speedo drive pinion gear, the gear retainer,and VSS.
It sworking but reading from 30-40mph over.
The dealer is now telling me that this truck should have a reverse gear reducer as well.
I had thought only the 4WD used the gear reducer? Anyone got a 93 D350 they can crawl under and look for me? Its a $110 part, so I dont want to spend the money if I dont need it and the problem is somewhere else....

No help on this? The parts guy at the dealership had two exploded veiws.. one wiht the gear reducer and one without....

Yes, mine has the right angle do-dad between the trans and the VSS.

Thanks Dave.. teh truck didnt have one on it when I got it, and with there being two pics of it, I want to be sure I am not wasting $$ Idont have...
"no returns on special order parts"..

Mine too.
There are two different versions. One for 3.54 and one for 4.10 ratios. My truck has the 3.54 reducer but I have 4.10 in the rear. Speedo reads 12mph(+/-) fast
Just for more info, you cant get drive gears to adjust the speedo like the other tranys (non Getrags) the Getrag has adifferent tooth geometry and MOPAR only has drive gears for slight (1 tooth) changes. So you need the correct ratio/direction adapter.
Bill

replaced the drive gear.. they had a hard time finding it in the book, so i finally pulled the old one and took it in for them to compare... got the correct replacement( assuming the correct one is in there in teh first place)
I have the 3:54 rear end and the #52 yellow(30 tooth count) speedo gear...

From what I can tell by looking at my '91 parts manual, you want the .625:1 ratio adapter, P/N 4428480. Gear number ought to be 2538930.

Thanks again dave.. I'll check on the number he ordered.

my '93 D350 has a green nylon gear that follows the worm drive on the tail shaft. The shaft from that drives what (local) Transport Control Systems calls a ratio drive, which I estimate @ 3:2 ratio. My VSS is on the end of that, and wired to the speedo head. Problem I had was a broken 1" shaft square one end and hex the other, square end driven by the output shaft, and the hex end driving the ratio drive. Couldn't get one so had to mill out a piece of Allen key square one end. Not pretty but it works. Dunno what my diff ratio is but my speedo checks out on the hi way marked miles, or marked "clicks" in our case.