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I can’t stop wizzing

CA650

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Joined
Apr 13, 2013
Messages
273
Actually a serious post.

My bronco makes a pretty noticeable whirring/wizzing sound right after startup and it seems to be mostly when in first gear. It’s a new sound and it coincided with a swap to my flex plate. it’s sort of a high pitched whir/wiz like a big gear spinning or a belt making a zzzzzzz sound.

My bronco ran well, no high pitched wizz/gear spin sound prior to this work being done. I know it’s a hard question to ask without hearing it but.. is this normal? I think it’s not since i’ve owned two broncos and only this one makes this weird and annoying sound. But my 69 bronco with the c4 didn’t wizzz like this and this 74 bronco didn’t use to sound like that either.

here’s what happened.
I converted from 3 speed manual to AOD no problem no strange sounds.

ran for a couple years with no problem but then had a starter malfunction.. stripped starter gears... no problem - i swapped in a new starter.. that one couldn’t engage properly.. could have been a bad starter but... I felt the edges of the flexplate and I thought some of the teeth felt rough so I decided to swap the flexplate and put a new/3rd starter in.

engine runs fine but this loud whine/wizz sound is present in low
gears and eventually as the engine is warm and I drive for a while it’s less noticeable .

to me it sounds likes it’s coming from the area near the flexplate and not the belts. I also don’t think it’s the belts because long after it started this sound, I swapped all the pulleys and belts for new when I did the recent timing chain cover and gasket job and the sound is present before and after this belt and pulley swap.

i know this is hard to debug without hearing it. i’ll try to capture the sound but i’m not sure my iphone will really pick it up.

Truth is that I don’t really trust the shop that did the flexplate job for me so I am suspicious of it and i’m wondering if anyone else has had similar issues.

this is a 302 with an AOD and the advanced adapters coupling.

the flex plate I used was the one in the picture below and summit link.
https://www.summitracing.com/parts/sum-g111sfi
I thought maybe just this flexplate has some weird acoustical characteristics.. maybe a different flexplate wouldn’t sound like that..
or someone did something wrong on the install. flexplates are cheap but the labor to put one in is not...

I think it was the correct plate for the AOD.
i’m looking for ideas.

maybe this?
Whining Torque Converter? —- the internet says - The most common issue with torque converters is damaged or worn out needle bearings, which arises due to low transmission fluid levels. If these needle bearings need to be serviced you will often hear a loud whizzing or grinding noise while your vehicle is in gear, but not when in neutra
 

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CA650

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Apr 13, 2013
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maybe I fried something when my transmission overheated twice.
I had a cooling problem that I think is now resolved but maybe there was some damage
 

El Kabong

Contributor
Driving stuff Henry built
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Oct 8, 2009
Messages
1,501
Sometimes you can get what I'd describe as almost a screaching sound when a starter doesn't disengage. If the starter is loose, crooked, wrong depth for the flexplate location, or a flexplate that isn't the right size, it might not be allowing the starter gear to retract.

Since you just changed the flexplate I'd think it will be something in that area. A loose torque converter nut, flexplate rubbing, & starter issues all come to mind. You might pull the inspection cover off & see what shiny places you can see in there with a flashlight.

As for constantly whizzing, I'd see a doc. They have pills for that.
 
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CA650

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Apr 13, 2013
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273
Sometimes you can get what I'd describe as almost a screaching sound when a starter doesn't disengage. If the starter is loose, crooked, wrong depth for the flexplate location, or a flexplate that isn't the right size, it might not be allowing the starter gear to retract.

Since you just changed the flexplate I'd think it will be something in that area. A loose torque converter nut, flexplate rubbing, & starter issues all come to mind. You might pull the inspection cover off & see what shiny places you can see in there with a flashlight.

As for constantly whizzing, I'd see a doc. They have pills for that.

Lol thanks. I could easily see the problem being something not put back together right. it has symptoms like I read about on the internet for a transmission problem with a torque converter.
 

75MIKE

Contributor
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Joined
Aug 22, 2001
Messages
963
Loc.
NE Washington
I had a shop that put the wrong flexplate in and filled the tranny full of metal. Was the wrong flexplate with too much dish and jammed stuff together.
 
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CA650

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I had a shop that put the wrong flexplate in and filled the tranny full of metal. Was the wrong flexplate with too much dish and jammed stuff together.

Right! that has been my experience too! Not necessarily with this transmission but the reason I now do most of my own Bronco work.

I had a new set of wilwood brakes put in backwards by my mechanic - more likely a kid that worked in his shop, I didn’t find that for almost a year untill a rotor bolt made contact with the brackets. totally unsafe. It took me three weeks but I replaced everything and put it back together right. in the process I found a large set of needle nose pliers the mechanic left in the engine..

Re: this flexplate - I believe it’s the correct one, I was careful sourcing it because the AOD transmission needs a different flexplate and different starter after the conversion.

My suspicion is that either something wasn’t put back right with the flexplate
OR I fried the transmission when it overheated a couple times before I fixed a problem with the fan and the transmission cooler.
the whining/wizzing sound is noticeably louder when I drop the transmission into gear in first or reverse.
 

Rustytruck

Bronco Guru
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Feb 24, 2002
Messages
10,875
what starter type original type or or newer type PGM starter if PGM how is it wired at the bronco solenoid.
 
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CA650

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Apr 13, 2013
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what starter type original type or or newer type PGM starter if PGM how is it wired at the bronco solenoid.

The starters come from Napa - I don't remember what the part # is i' have to crawl under there again and check it. Its wired directly to the right side of the solenoid and the engine block is the ground.

Engine fires straight right up. I don't suspect that its the starter failing to disengage but that is a thing to consider.
The noise comes in when the truck is put in gear.

Going to see a specialist I think.
I made an appointment at Bayshore near Burlingame, CA
Phone: (650) 579-7711

I spoke to them live and at least they said they had done one C4 to AOD conversion and were aware of advanced adapters etc. I'll let you know what I discover.
 
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gr8scott

Contributor
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Jul 1, 2011
Messages
1,857
The original style is larger and quite heavy. The PMGR mini starter is smaller, about half the weight, uses about half the power, and spins about twice as fast.
I love my PMGR starter, picked up from WH in 2011, still going strong.

Old on the left, new on the right.
https://www.youtube.com/watch?v=d6cF-J1iAsw
 

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CA650

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nothing yet, I was just about to read your thread to see what you found out.
I think I either smoked the transmission from a couple of overheatings or what I wrote earlier. either way I think I need to drop the transmission to find out
 
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CA650

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I wrote this thread because the wizzing noise I hear in low gear and when I put the bronco in gear was annoying. But the transmission has finally failed and I could use some help diagnosing it.

Now the transmission is slipping and the Bronco won’t move unless The engine is revved pretty high. It’s like the clutch or torque converter is not engaging. Reverse is a little better than forward/drive but the truck is not really drivable

The transmission is an AOD that I put in new a few years ago with the Advanced Adapter used to replace the 3 speed manual. I have a carbureted 302 with the lokar linkage to the transmission.

This has run fine for me for years but I overheated the transmission badly on a few long drives before adding a dedicated transmission radiator. I had some starter issues recently and fixed those and because I felt a few of the teeth might be fouled on the flexplate I put a new one in (even though the flex plate was new a few years ago when I did the transmission) anyway I had a local guy put this flexplate in for me. It was a lot of work and I didn’t have time. When I got the truck back the flexplate (or something under there) was making this wizzing sound that bugged me but I lived with it... might be unrelated IDK

What I do know is that the transmission is not engaging now unless the engine is revved pretty high so something is stuck or slipping in there...

What do you think? Is the torque converter a suspect? And is that a consumable part that could fail or is that unlikely?

I’d like to get the truck back on the road ASAP.. should I buy a new AOD and drop that in while I send the current one out for service?

Can’t remeber how much the AOD cost me.. I see them for $1500 and I see them for $3k what do they cost these days and where should I be shopping (I’m in Northern California)

I think I bought this unit from BroncoParts4you.. I think I heard the owner passed away a few years ago? Idk.

Looking for advice on the fast path to get the truck up and operational.
 
OP
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CA650

Full Member
Joined
Apr 13, 2013
Messages
273
I wrote this thread because the wizzing noise I hear in low gear and when I put the bronco in gear was annoying. But the transmission has finally failed and I could use some help diagnosing it.

Now the transmission is slipping and the Bronco won’t move unless The engine is revved pretty high. It’s like the clutch or torque converter is not engaging. Reverse is a little better than forward/drive but the truck is not really drivable

The transmission is an AOD that I put in new a few years ago with the Advanced Adapter used to replace the 3 speed manual. I have a carbureted 302 with the lokar linkage to the transmission.

This has run fine for me for years but I overheated the transmission badly on a few long drives before adding a dedicated transmission radiator. I had some starter issues recently and fixed those and because I felt a few of the teeth might be fouled on the flexplate I put a new one in (even though the flex plate was new a few years ago when I did the transmission) anyway I had a local guy put this flexplate in for me. It was a lot of work and I didn’t have time. When I got the truck back the flexplate (or something under there) was making this wizzing sound that bugged me but I lived with it... might be unrelated IDK

What I do know is that the transmission is not engaging now unless the engine is revved pretty high so something is stuck or slipping in there...

What do you think? Is the torque converter a suspect? And is that a consumable part that could fail or is that unlikely?

I’d like to get the truck back on the road ASAP.. should I buy a new AOD and drop that in while I send the current one out for service?

Can’t remeber how much the AOD cost me.. I see them for $1500 and I see them for $3k what do they cost these days and where should I be shopping (I’m in Northern California)

I think I bought this unit from BroncoParts4you.. I think I heard the owner passed away a few years ago? Idk.

Looking for advice on the fast path to get the truck up and operational.
 

EPB72

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Joined
Jul 13, 2019
Messages
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Loc.
Pleasant Hill, CA
Does the fluid smell burnt discolored maybe greyish/metalic color??? or clean red color?.

Drop the pan and inspect for metal debris in pan..From your previous post probable torque convertor issue and now slipping , As a tech a complete teardown/rebuild or replacement are your options no shop is going to do a partial repair that they can't warranty..
 
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CA650

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Fluid looks/smells ok to me.
re: a complete teardown/rebuild - I was afraid of that but it seems right since the labor to sort something out like this probably more than the labor to buy, install/replace.

But what about the wide variation in cost of these transmissions? I've seen $1500 and I've seen $3500 any advice on where in the bay area CA to shop? I'd like to just drop a new one in, send the old one out for re-build and then I'll have a spare that i can drop in myself at some point if i ever need to,
 

EPB72

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Messages
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Loc.
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Most trans we replace are Jasper they have 3 year warranty and nation wide the warranty process has been good compared to other warranty companys we've delt with ....

I f you get a replacement more then likly there going to want a core so ask about a core charge i've seen 200 to as high as 700 dollars for core ....also having a trans sit around 10 ,15 years maybe longer does that make sense???

as far as south bay shops really don't know ,,
 

DirtDonk

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Bronco Guru
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Nov 3, 2003
Messages
48,811
There's another possibility. Maybe...
If the filter/pickup has fallen out of it's press-fit hole you will sometimes lose pressure in the fluid and it can do all sorts of mischief.
This is also a fairly common issue with automatic transmissions. At least for Fords.

Worth a quick look into the pan before deciding to rebuild it would seem to me.

Paul
 

73azbronco

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Or, I thought I had a squeeling sound I could not locate, it was the air cleaner sound of air rushing through closed throttle plate on carb.
 
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CA650

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I dropped it off at bayshore transmission. Tom is taking a look at it. Lets see what he says.
He said he has done a few AOD transmissions he also said that the 28oz flexplate comes in multiple versions - I didn't know that so I likely have the wrong flexplate on there too.



IDK.
 
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CA650

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Update on this. The zipping/wizing type sound was something starting to fail in the torque converter. I’m on the peninsula in the Bay Area, CA and Bayshore transmission took care of it and offered to warranty their work which was really nice.

New torque converter and then when they road tested it they felt like the shift points were off between the 2/3 gears and they ended up swapping out the valve body too. It’s driving and shifting great now.

Unfortunately - ended up smoking the drivers side caliper and rotor last week on my wilwood front disks. Something must have been wrong with the pressure or alignment of the front left caliper.. another $1K of wilwood parts from summit this week. I’m going to focus on making sure the rotors are really well centered and that their is no pressure on the pads and I’m looking into the brake proportioning valve, I think I was running a stock proportioning valve with wilwood disk fronts and master cylinder.. probably another thread to post on this one
 
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