I've done some searching, but haven't found this exact issue.

I have an '85 with the Doug Nash 4+3. I've had it for 8 years and regularly changed the tranny fluid. It is now doing something that it has never done before.

When driving, and then engaging the OD, the rpm's sometimes drop, sometimes they do nothing. The light does come on indicating OD in operation. It almost acts as if it is slipping.

Today, the rpm's would drop, but the instant ANY load was put back on the engine, the rpm's would increase to the level they would be at if the OD wasn't engaged AND the light stays on. At no point is the light going off, as happens when the tranny will "kick down" into passing gear. It stays on continuously.

My first thought was it was low on fluid. I added about 8-10 ounces before it came out of the fill plug. Some of that was spillage. I then took a test drive and got the results mentioned above.

I do have a manual, and am capable of doing most things it suggests. Where I struggle is with electrical and chasing those demons.

I'm asking if anyone has had a similar experience or if someone can point me in a direction.

I'm thinking of the following as issues:

-relay (I did run the diagnostic, grounding A-B and the light came on)
-pressure switch (not sure how to test)
-relay harness (I've had it off recently to put some liquid electrical tape on the shrinking wire covering and added dielectric grease on the contacts)
-OD unit (my hopes are that it isn't this, and since I haven't lost reverse, I'm optimistic that it is something listed above or something I've missed)

The fact that the rpm's will drop if there is no "load" on the engine has me puzzled. That may be the key fact in all of this diagnosing.

Thanks for any replies.

Steve

 

hmmm...call Brian at SK Speed (in NY) and tell him what you posted here. They are the ONLY shop i trust with any 4+3 issues. Have you lost "engine braking" when you down shift (with OD on or off...doesn't matter)? How does the OD fluid look? If its got chunks in it, or the pan magnet is covered in clutch material, get ready to replace to unit, although i don't think thats your problem.

give us an update when you get a final answer.

 

Here's the info for S&K:

S&K Speed
631-957-9427
Brian
skspeed.com

 

I spoke w/ Brian the other day and he basically said that it is on its way to being toast.

The inner and outer race have worn, the car does have 165k on it, and basically the bearing is about to go. It can't hold once the load is put on it.

I'm thinking of going with the t5 swap. Anyone want to talk me out of it?

 

Today I drained the fluid, and it looks like mud and smells burnt. I was hoping to find some good-bad news in there, like no 12v to the pressure switch or something like that. No good news in this.

Anyone know where I can get a T5? I'm looking on ebay, any other sources recommended?

Thanks!

 

I am assuming that you have found the excellent information on this website setup by a forum member:

http://members.cisdi.com/~anesthes/f-car-t5/

As best as I can tell, the T5 is the best setup for a stock powered car when cost is a consideration.