Questions about the Warn ovderdrive with D18 / T90

[spenceuiuc]

I recently removed a t90 mated to a Dana 18 with a warn od attached from some parts scouts I just bought (anybody need parts from a '65 or a '67 with a sportop?). I am not very familiar with the overdrive units, but am excited to get some additional gears onto the 1962 Scout 80 I am working on.

I was testing out the t90 before I swap it into the Scout (turning input shaft by hand, shifting through gears) and it seems to go through all the gears smoothly. When I engage the od, the input shaft becomes quite a bit more difficult to turn, and as expected the output shaft rotates more per rotation of the input shaft, so the od seems to be working. However, when engaging the od, there is not a very noticeable feel of shifting between gears (or clicking into gear) like when shift into a gear on the transmission.

So here are my questions:

1) should the input shaft be significantly more difficult to turn with od engaged? I know it should be a bit tougher as your spinning the output shaft more, but it seems like it might be more difficult than it should be.

2) when engaging the overdrive, should there be a very noticeable feel of shifting between gears like when shift between gears on a transmission (I.e., should I be able to feel a distinct click when engaging the od)?

Sorry about my novice questions and thanks for any input on this one.

-tony

 

[Greg R]

1) should the input shaft be significantly more difficult to turn with od engaged? I know it should be a bit tougher as your spinning the output shaft more, but it seems like it might be more difficult than it should be.

If by output shaft you are referring to the transfer case's output shaft, yes it will be more difficult. You are speeding up the whole transfer case(and oil bathed) as they are constant mesh. How much more difficult I can't say as I never thought to "check" that scenario. Driving it will bring out any strange noises or problems. Just go.

2) when engaging the overdrive, should there be a very noticeable feel of shifting between gears like when shift between gears on a transmission (I.e., should I be able to feel a distinct click when engaging the od)?

The od shifts pretty easily with no clear detent feel like a transmission. All that's being done is sliding the synchronizer slider ring or collar to lock the spline shaft to the bowl gear for direct or the case for planetary action speed change. There's not a lot of mass to move or change speed for engagement. You can increase spring tension on the poppet ball for the shift rod to get a more positive feel of shifting though it will be harder to move.

 

[spenceuiuc]

if by output shaft you are referring to the transfer case's output shaft, yes it will be more difficult.

Oops, didn't clarify that very well in my 1st post. By input shaft, I meant the t90 input shaft--- the t90/d18/od are all still mated to one another. Still got the info I needed from your response though--- thanks, greg r.