3 speed RAT trans noisy in 3rd gear?

[Bustedbroc]

74 stock EB, 302 3 speed RAT trans finally on the road and sorting out the bugs. All new, clutch, u-joints, seals, axle bearings, fluids, etc. Truck drives well EXCEPT when in 3rd gear and NOT under a load. Quiet during acceleration or deceleration. I get a noise that I THINK is the trans. Sounds to me like a worn thrust washer or something. A rattle/whine. When I had the rear diff out changing the fluid I could see that the truck must have sat with moisture. Portions of the ring n pinion have some rust/pitting but it only makes the noise in 3rd gear. Checked thru the posts but couldn't find anything close to the same. Thoughts anyone? FYI, when the trans was out and I had the top cover off to clean it out, it looked pretty clean except for the normal type of sludge found in old gear oil. No filings and the gears looked good to my eye. Trans seems to shift pretty well also. Thanks.

 

[DirtDonk]

You said it’s stock, but does that mean suspension also? No lift or other modifications?
You replace the u-joints, but did you do it yourself or have someone do it?
Reason I’m asking about this, is driveline vibration can transmit itself from the rear end, through the driveshaft, right up into the transfer case and transmission.
The fact that it happens in third only, does tend to point to the transmission. But it’s not 100% guaranteed.

 

[Bustedbroc]

You said it’s stock, but does that mean suspension also? No lift or other modifications?
You replace the u-joints, but did you do it yourself or have someone do it?
Reason I’m asking about this, is driveline vibration can transmit itself from the rear end, through the driveshaft, right up into the transfer case and transmission.
The fact that it happens in third only, does tend to point to the transmission. But it’s not 100% guaranteed.

All stock, no lift. I did all the work myself. Tight, quiet, smooth and greased. Only in 3rd gear and a hard noise for mean to describe with words but it sounds like something is worn/loose whether it be a bearing/bushing/thrust washer. Like there is too much lash somewhere. No grinds going into gears unless I shift too fast, then it may crunch a bit. I did install a Duff floor shifter to replace the 3 on the tree. I was just wondering if the RAT trans has a weak link that is common.

 

[DirtDonk]

My 71 should have the same transmission as your 74 (I thought anyway) and the only thing that ever broke on that one was the rear main output bearing when I was doing a reverse burnout. With the original gear lube and very low.
So it was a three strikes kind of a thing.
Otherwise, they are generally very reliable unless abused.

When that bearing grenaded, it made a harsh rattling noise that mostly went away, and only returned under certain circumstances. It never made a constant noise in any gear.
When you’re in third gear, the input and output shafts are locked together. So you’re kind of right thinking it would be a bearing. Only the two main bearings are in full play at that point, but someone else will have to answer the question as to what the countershaft and idler gears are doing at this point.
Maybe it’s one of those.

Sounds like it’s all new fluid in the trans. Correct? Did you double check its level just to be sure?
What type of lube did you use by the way?

 

[DirtDonk]

Oh, and you installed the transmission just as it was when you bought it, correct? It was never gone through or rebuilt?

 

[Bustedbroc]

Oh, and you installed the transmission just as it was when you bought it, correct? It was never gone through or rebuilt?

Funny you should ask about the fluid. I double checked this am since I filled it per owners manual when the trans was out. It is full drooling out. That is the type of noise though, metallic rattle. Really didn't drive truck when I got it. Pulled trans and xfer case, cleaned then up, inspected trans thru the top cover, and replaced seals. Tranny looked good to me but what do I know. I did not separate trans and xfer case. I guess it could be transfer case? I would think it would make the noise is all gears even though with 4.11's 1st and 2nd don't really "coast". Also, I had the truck up on jackstands. Really only heard it in 3rd. FYI, There is no cardan coupling on the rear drive shaft.

 

[DirtDonk]

Well, I hate to say finish putting it together first, because that’s just a little more work for you, but I don’t really know what, if any, noises might come from running it all unloaded like that.

Since the only real changes is putting on the driveshaft, I would do it.
Get it out there running before you pull the transmission out again, and just see how it sounds when it’s driving around.
If you still have the noise, then fine, go ahead and pull it apart and see what’s up. Until then, I wouldn’t make too much hay on it until you’ve loaded it.

 

[Bustedbroc]

Well, I hate to say finish putting it together first, because that’s just a little more work for you, but I don’t really know what, if any, noises might come from running it all unloaded like that.

Since the only real changes is putting on the driveshaft, I would do it.
Get it out there running before you pull the transmission out again, and just see how it sounds when it’s driving around.
If you still have the noise, then fine, go ahead and pull it apart and see what’s up. Until then, I wouldn’t make too much hay on it until you’ve loaded it.

DD, I should have said I "also" had the truck up on jackstands. Truck is on the road and the symptoms described are during normal driving. Sorry bout the confusion.

 

[DirtDonk]

Ah, ok. Not a problem. I probably wasn’t following along closely enough in my head.

 

[DirtDonk]

And just to be sure… Your transfer case is verified 2 Wheel Dr. Correct? You can reach under there and spin the front drive shaft easily by hand?

 

[Bustedbroc]

And just to be sure… Your transfer case is verified 2 Wheel Dr. Correct? You can reach under there and spin the front drive shaft easily by hand?

Yes, correct. When I had the tranny/xfer case out I replaced the J shifter with a 2 stick from Jeff's. I also replaced the 3 on the tree with a Duff floor shifter. I think I may put all 4 wheels up in the air and just engage the front drive to see it it makes the noise. Im not too worried about the noise. Trans shifts great. Believe it or not, the more I drive it the more I almost suspect it's one of the shift rods rattling. Thanks.

 

[Bustedbroc]

UPDATE: 1974 EB 302 purchased 10/23. It appears that the noise I hear is coming from the rear and resonating up the driveshaft. Strange because when you drive it seems like it's from the trans area. I was starting to think it was shift linkage rattling but I eliminated that. Also it REALLY is noticeable only in 3rd gear. My friend and I put it up on jack stands to try to eliminate things. With a 2 stick xfer case setup I could engage just the front axle, no noise. With the just the rear engaged what a racket. Also, turning the rear driveshaft back and forth by hand there seems to be ALOT of lash/slop. In 3rd gear that rear is really spinning I guess. If you listen close you can actually hear it a bit coasting in neutral. Over the winter I had The rear diff out changing the gear oil and replacing the axle bearings. Upon removal it was clear that the diff had issues. Water in the diff and pitting on some of the pinion/ring gears. I decided to roll the dice and run it since I had so many other issues to address at the time. Well looks like I am full circle now. Ford 9" factory 4.11 limited slip. Any tips on rebuild kits or where to get a GOOD center section to swap in? I would like to keep the cost as close to $1k, (or less?) if possible. I am a bit skeptical of some of these gear sets. This truck will never see any real serious offroad or daily use in my ownership. Thanks.

 

[Speedrdr]

Here’s a company that has complete 3rd members for Ford 9” rears, Speedway Motors, and they are under $1K. Southwest Speed also has complete 3rd members under $1K. I’m sure that Currie Enterprises has them but no idea of price. Hope this helps.

Randy

 

[Bustedbroc]

Yes, thank you. Google search shows Speedway and others, ( NEclassicford, quick performance, etc). Some new, some rebuilt. I guess what I am asking is does anyone on this forum care to recommend one over the other? I am tempted to go with one of these if anyone has experience with this vendor.

Ford 9" inch rebuilt center section / third member limited slip, posi

Ford 9" inch rebuilt center section / third member limited slip, posi

www.northeastclassicfordparts.com

 

[Bustedbroc]

Yes, thank you. Google search shows Speedway and others, ( NEclassicford, quick performance, etc). Some new, some rebuilt. I guess what I am asking is does anyone on this forum care to recommend one over the other? I am tempted to go with one of these if anyone has experience with this vendor.

Ford 9" inch rebuilt center section / third member limited slip, posi

Ford 9" inch rebuilt center section / third member limited slip, posi

www.northeastclassicfordparts.com

Also, since the truck is still usable for local cruises, is there a way to ID/verify EXACTLY what I have to order a replacement before I yank the axles and remove the center section? From what I have read on this forum it is 99.9 % 28 spline, VIN shows 4.11 gears, but I thought I read something about different yokes or pinion bearing sizes?

 

[.94 OR]

I don't mean to cause mission creep, but are new axles in the budget? Seems folks are experiencing metal fatique in this area and it could save you some additional grief in the future.
Reason I ask, if you are replacing the center section and then possibly axles, you could move from a 28 spline to a 31 spline for close to the same dollar and have a little stronger axle despite you saying it won't do much more than make ice cream runs.

 

[Bustedbroc]

I don't mean to cause mission creep, but are new axles in the budget? Seems folks are experiencing metal fatique in this area and it could save you some additional grief in the future.
Reason I ask, if you are replacing the center section and then possibly axles, you could move from a 28 spline to a 31 spline for close to the same dollar and have a little stronger axle despite you saying it won't do much more than make ice cream runs.

Eh, I hear you but where does it ever end?

 

[.94 OR]

You think there's an end?

 

[Shimmy]

maybe something to consider, but check with these vendors on their build times or if there items are ready to go. I bought my 3rd member from Quick Performance in May and I'm still waiting for it to ship. I think they last told me mid-August? Quick had the best pricing for what i wanted, but i didn't anticipate the wait time till 2 weeks after my order and i was wondering when i'd get a shipping notice. Some of these vendors also have a 15-20% restock fee even though their items are on shelf.

 

[Bustedbroc]

maybe something to consider, but check with these vendors on their build times or if there items are ready to go. I bought my 3rd member from Quick Performance in May and I'm still waiting for it to ship. I think they last told me mid-August? Quick had the best pricing for what i wanted, but i didn't anticipate the wait time till 2 weeks after my order and i was wondering when i'd get a shipping notice. Some of these vendors also have a 15-20% restock fee even though their items are on shelf.

Good tip, thanks. I also read somewhere on one of forum threads knocking the factory Ford limited slip.