so we finally finished my project.... a year later..... and one part being swapping out the 700r4 for a zf. i bought it brand new. it shifts fine and everything. but when the clutch is not engaged, there is an obvious rattling. i have no clue what it is. i searched for reasons why, but i couldnt find a straight answer.

 

Does it sounds like rocks in a can? Did you use a aluminum fly wheel? Does the sound go away when you depress the clutch?

 

exactly what it sounds like, i used a steel flywheel, and yes... it makes no noise with the clutch engaged

 

That just the ZF trans. It rocks the loudest when the trans heats up, and the oil thins down. You are lucky, it worse with the aluminum fly wheel.

 

that sucks. it just sounds so wrong. but thats kinda the same answer i found when doing my own research. but all i could find was about the ford diesel zf's. and they had the same thing going on. thanks very much. looks like ill be turning the volume up higher nowadays

 

. . . this is your former automatic transmission talking. . . .I told ya so.....

 

 

Also not happy with the ZF trans noise & I was about ready to pull it & put either a 5 or 6 speed in that I have in the shop. Going against all that is posted about the quality & weight of the trans oil that is required & considering the fact that I was ready to pull the POS out anyway & throw it in a corner I drained the trans & installed 90W synthetic & one bottle of STP with the following results:
Note: I stll have the stock dual mass flywheel. The vehicle had 32K on the clock when the trans oil was switched.
At idle with the clutch out it makes a whirring noise & does not rattle.
It has a nice gear whine through 1, 2 & 3.
At cruise in 4th it has a slight "chuckle" noise which I contribute to the counter shaft just being along for the ride. This is speculation on my part, without opening the trans or investigating parts illistrations the counter shaft on most manual transmissions is just along for the ride when the trans is in a 1 to 1 gear ratio.
No change in gears 5 & 6.
When the engine is cold @ 30* shifting effort has increased a small amount but returns to what I consider normal after 3 or 4 trips through the gears.
I have only put 2k on the trans since the oil change & so far I am pleased with the results. I work it through the gears quite a bit on the 2 lane mountain roads & if it makes it through the summer without a failure I'll keep it in the car & install a short throw shifter.

 

I'd be real careful about putting 90W in a ZF6. Neither of the recommended fluids are anywhere near that thick. 90W also dosn't have the correct additive package to be safe on the synco's.

I'm surprised it shifts at all. Some ZF6's won't even shift right when you use one or the other of the recommended oils.
Will

 

I will be more specific. I do not care for or about this transmission. The oil change is just something I thought I would try before pulling it out. It will find a new home in the corner of the barn anyway when the alloy flywheel gets installed.