Whining Noise in Rebuilt C4

[RM351 207]

I had my C4 trans rebuilt a few months ago, before it was rebuilt It had a whine to it.

Now it's rebuilt the whine is still there. This noise is consistent when idling, going through each gear, just the pitch changes when revving higher.

Went under the bonnet and the sound coming from the rear of the engine so I'm assuming it's the transmission. Took it back to the transmission builder and he said it's normal for a C4 to make a noise after being rebuilt.

I had a C4 rebuilt years ago in another car I had and I don't recall any whining noise so I'm a little sceptical of the builder response.

 

Anyone now if this true and what's causing this whine?

[Rod Racer 273]

No, it's not normal, but they are getting on and new replacement gear sets are harder to find. I had one years ago that was noisy, so I changed the filter in the pan and used Castrol TQF fluid, and bugger me if the noise disappeared, never to return. Make sure the correct fluid is used (TQF), NOT Dexron 2 or 3, it's too thin for the C4/C6 transmissions. If it whines at idle, that is usually a blocked filter and/or too light a fluid.

[RM351 207]

The C4 has only done 1400k's so far, surely the filter isn't blocked already?

 

I'm using Penrite Type F fluid, is the Castrol TQF fluid similar or better?

[gregaust 332]

Certainly not normal. What type pan and filter ? By chance a Dacron filter ? Like a B+M pan comes with?  Not seen it in a Ford but VERY common in T400 to make odd noises if a dacron filter is used , restricting pump feed 

 

Dexron fluid works fine and wont be the cause of the noise 

[RM351 207]

I have a Peformance Automatics Deep Pan PA-26404 and TCI filter to suit deep pans TCI-528550.

[Rod Racer 273]

18 hours ago, RM351 said:

The C4 has only done 1400k's so far, surely the filter isn't blocked already?

 

I'm using Penrite Type F fluid, is the Castrol TQF fluid similar or better?

Penrite Type F is very good, likewise Castrol TQF. I mention these 2 because both are very good in severe use (trans brake @ 4000 rpm flat throttle hold), as I can attest to, having used both.

Do NOT use Dexron 2 or 3 in early Ford Transmissions (C4/C6), unless you like rebuilding them often. I speak from experience. Their pumps don't work well with the thinner fluid.

I also change filter and fluid after the first 1000 km of use, regardless, as the new parts wearing in create some debris that can restrict the filter, and as mentioned, don't use the dacron filters.

[RM351 207]

On 12/6/2024 at 10:15 PM, Rod Racer said:

I also change filter and fluid after the first 1000 km of use, regardless, as the new parts wearing in create some debris that can restrict the filter, and as mentioned, don't use the dacron filters.

 

Yeah looks like it's what I need to do,  check the filter and see what's going on.

[Rod Racer 273]

7 minutes ago, RM351 said:

 

Yeah looks like it's what I need to do,  check the filter and see what's going on.

It's not unusual to have a lot of trash block the filter in rebuilt units.

[RM351 207]

OK, did a quick video of how it sounds.

 

 

 

I've taken the pan off and it looks pretty clean.

 

 

Filter looks fairly clean.

 

 

 

So could it be the front pump making the noise or convertor?

[gregaust 332]

Really need to look at the pump first . Since it was noisy previous the clearances in the pump and crescent "should" of been checked.

 

It "should" of had new pump bush fitted.  

 

if there is contact with the crescent to inner gear there is a mod you can do 

 

Was converter split open or replaced during the rebuild?   If it was then comes back to pump. If it wasn't then it possibly could be converter 

[RM351 207]

3 hours ago, gregaust said:

Really need to look at the pump first . Since it was noisy previous the clearances in the pump and crescent "should" of been checked.

 

It "should" of had new pump bush fitted.

He was told about the noise when I dropped the transmission off. I'm thinking he's forgotten about it after it took 7 weeks to have it built even though he said it would be ready in 2 weeks.

 

3 hours ago, gregaust said:

Was converter split open or replaced during the rebuild?   If it was then comes back to pump. If it wasn't then it possibly could be converter 

I asked if he could increase the stall so I don't know if he actually did it or not. The convertor is painted that's all I know.

[RM351 207]

Another issue I have with the transmission, the oil is spitting out of the breather only when I put my foot down. Checked oil level and its not over full.

 

Think I'm regretting taking the C4 to this guy.

[Rod Racer 273]

I could have sworn it was just a blocked filter, obviously, I was wrong. It appears there are other issues causing your problems. I'd be going back to him and complaining. He might fix the problems, he might not (most likely).

[RM351 207]

7 hours ago, Rod Racer said:

I could have sworn it was just a blocked filter, obviously, I was wrong. It appears there are other issues causing your problems. I'd be going back to him and complaining. He might fix the problems, he might not (most likely).

Seems like these days there's not many people taking pride in their work, all they care is the $$$$$$.

See what happens, he did say if the noise gets worse come back to him, probably come up with some other BS excuse.

 

Did some research about transmission oil pissing out of the breather when stomping on the accelerator There are two possibilities I found which is overfilling (which is not the case for me) or transmission filter valve is missing.

 

This:

 

Which goes in this:

 

The spring is there but not the valve. Hopefully that will solve the issue once I get one.

 

[gregaust 332]

Oh now that valve missing is a hug issue. How the hell did someone rebuild and leave that out? Just WOW !!!!!     With that missing it's a wonder it's not slipping.

 

As to oil level , be sure to verify the stick is correct. Run sting alongside tube and see where the "full" level is exactly 

[gregaust 332]

With that valve missing , the guy clearly has no idea what he is doing. What else was done to valvebody? Makes me want to question if pressure reg valve is fitted right or what else he might of F___ked up

[Rod Racer 273]

My advice (hard earned) is to use the FACTORY tube and dipstick. Do NOT assume an aftermarket tube and dipstick will read correctly (almost all do NOT). I know this from bitter experience. The AOD in my F100 always spewed out fluid from the breather at the 'correct' level, until I sourced a factory Ford tube and dipstick, to find it was almost a quart overfull. Now, no more breather spillages and no more frothing fluid trying to exit the tube when checking.

Just my $0.02.

[RM351 207]

5 hours ago, gregaust said:

With that valve missing , the guy clearly has no idea what he is doing. What else was done to valvebody? Makes me want to question if pressure reg valve is fitted right or what else he might of F___ked up

This is what's done.

[RM351 207]

3 hours ago, Rod Racer said:

My advice (hard earned) is to use the FACTORY tube and dipstick

 

Not easy to find a good one plus isnt there a fitment issue with extractors?

[Rod Racer 273]

24 minutes ago, RM351 said:

 

Not easy to find a good one plus isnt there a fitment issue with extractors?

Never had any issues using headers (Tri-Y or 4 into 1's). I'm sure I DID have a dipstick and tube for a C4 somewhere, I'll have to have a look.

[Rod Racer 273]

Just listened to the video. I'm gonna say, that is the flex plate rubbing on the sandwich plate. Either the plate has a dent or buckle in it, causing it to rub on the flex plate and/or convertor nuts/studs, or the convertor is not fully seated and is forcing the flex plate forward to touch the sandwich plate. If you had this same noise before, something isn't sitting right there. The other cause could be using an aftermarket manual starter, which has a shorter snout, it could be interfering on the flex plate teeth. The factory used a spacer under the standard factory starter because the flywheel ring gear sits closer to the block rear face than the flex plate does. The whine I had in my C4 was MUCH quieter and more high pitched.

[RM351 207]

On 12/26/2024 at 8:54 PM, Rod Racer said:

I'm gonna say, that is the flex plate rubbing on the sandwich plate. Either the plate has a dent or buckle in it, causing it to rub on the flex plate and/or convertor nuts/studs

Flex plate is new and I'm assuming it's the correct one for the C4.... Pioneer FRA-205.

 

On 12/26/2024 at 8:54 PM, Rod Racer said:

or the convertor is not fully seated and is forcing the flex plate forward to touch the sandwich plate. If you had this same noise before, something isn't sitting right there.

Is it possible to check that without pulling the transmission off like undoing the convertor nuts and see if there's some movement?

[Rod Racer 273]

8 hours ago, RM351 said:

Flex plate is new and I'm assuming it's the correct one for the C4.... Pioneer FRA-205.

 

Is it possible to check that without pulling the transmission off like undoing the convertor nuts and see if there's some movement?

May be contact with a buckled sandwich plate. Don't assume it's the correct flex plate, make sure.

 

Yes, undo the nuts and see if you have some movement in the convertor on the studs. Should have 2 - 4 mm movement, at least. More could be an incorrect flex plate (unlikely, but possible).

[deankxf 20,904]

I've had that sandwich plate rubbing before on a clevo/C4 combo. definitely worth checking. 

I'd also tip water over the fan/alternator belts, as silly as it sounds i've had them causing noises that sound nothing like you think

[RM351 207]

Righto, may have an issue, I removed all the convertor nuts and could not move the cnvertor back or forth. Even gave the convertor a bit of a tap with a flat punch and hammer, no movement at all. So I'm wondering if the covertor is not in properly causing it to be tight against the flexplate.

 

I do remember the convertor bolt holes on the flexplate not being perfectly aligned by only a smidgen, wasn't easy getting the transmission in. I thought abouty making the holes bigger but was concerned about affecting the flex plate balance.

So there is a chance while I was battling to get the transmission on, either the convertor move forward a bit or the convertor is not sitting flat on the flex plate.

 

Have to say while turning the engine manually didn't feel any unusual resistance either.

 

 

 

Don't think the staerter motor is an issue.