On the way home from the store, truck warmed up, it shifted into OD at 37ish MPH and it felt like it was vibrating a bit. So at the next light I took it out of overdrive and got to 40 and it felt okay.
Then a couple miles down the road, I noticed an odd noise and thought it was car next to me. Same noise at the next light - like a fan blade hitting something.
Put the truck back into OD and it vibrated again. Did this at as I accelerated at every light or stop. Seemed to be tied to engine RPM a couple times. It's a hard feeling to describe. As if a tire is slightly out of balance.

Thoughts?

Thanks

 

Are you able to scan for codes?

Here is a bump at least.

 

I think the first thing I would suggest is that you pull the inspection cover off between the engine and transmission and make sure that you aren't dealing with a cracked flex plate. That sounds a lot like a cracked flex plate to me. Make sure that you can't move the ring gear forward and back and that everything looks good and tight in there.

 

This is what I thought of when I first read this thread, but I'm not an auto guy so i let the experts give their opinion.

 

Would it make sense that it did not do it consistently?
I imagine the trans has to be dropped to replace that.

 

Yes they can be intermittent and yes the trans has to come out to replace it.

 

Interesting. Would it effect the starter at all?

 

Yeah it could if the flex plate is completely broken. If it were me, I wouldn't drive it until you get a chance to check it out. That's a good way to bust the bell housing on the trans.

 

Will do. I'll pull the inspection plate this week.
If I drop the trans, I'm going to put the ZF5 I have back in

 

That's a pretty common swap. Was the truck originally a ZF truck? You have all the necessary parts and pieces to make the swap (PCM, Trans crossmember, driveshafts, clutch pedalbox,etc)? Auto vs Manual debate aside, the ZF is a more "bulletproof" setup in my opinion. This coming from a guy that currently needs to replace his clutch, (me) lol.

 

Hmm. Not sure why I wrote "back in" but no the truck is an all original e4od.
I have the drive shafts, trans, SBC clutch/flywheel, clutch/slave set up and pedals. I need the xmember, floor pan and rear trans harness.

 

Floor pan and xmember can be modified. I currently run both modified from an E4OD. Although I would prefer (and I'm currently looking) to run a true ZF xmember, just letting you know that can work. The floor pan is just a simple cutout.

 

You'll also need either the clutch safety switch and a manual PCM or to plan to do some wiring magic to make everything work. And the transmission is from a diesel pickup, correct (just making sure you know you can't use one from a gas engine)?

 

Well you can redrill a 460 ZF5 but some people don't like the gearing, at any rate yes the one I Have is from a diesel.

I will acquire a clutch switch as well. The automatic PCM Will work but people do prefer the manual programming.

 

Pulled the inspection plate down and it all seemed tight. What am I looking for exactly?

thanks!