Gear whine while accelerating

[Synyster06Gates]

Yes one more thread! My Cobra has a SRA swap with 4.10s and when I accelerate I notice a bit of gear whine. I knew that I was low on diff fluid so I changed the pinion seal and filled it up. The whine is still there, so I was just wondering what the issue could be. I know it has to do with the backlash of the gears, which can be adjusted at the pinion nut so I wanna give it a shot. If it's a bit of whine while accelerating, but fine while coasting and decelerating, which way should I turn the pinion nut and how much would you recommend turning it at a time?

Thanks!

 

[Wildman113]

Yes one more thread! My Cobra has a SRA swap with 4.10s and when I accelerate I notice a bit of gear whine. I knew that I was low on diff fluid so I changed the pinion seal and filled it up. The whine is still there, so I was just wondering what the issue could be. I know it has to do with the backlash of the gears, which can be adjusted at the pinion nut so I wanna give it a shot. If it's a bit of whine while accelerating, but fine while coasting and decelerating, which way should I turn the pinion nut and how much would you recommend turning it at a time?

Thanks!

You have 3 possibilities:

A bad pinion bearing
Noisy gears (bad cut)
Incorrect gear pattern (pinion depth/backlash)

None of these can be corrected by turning the pinion nut. In fact, turning the pinion nut will do absolutely nothing besides tighten or loosen the preload on the pinion bearings. The pinion bearing preload should be a certain spec measured in in/lbs or rotating torque, and is set when the pinion is installed.

The pinion depth (how far it meshes into the ring gear) is determined by the shim that is installed behind the gear itself and cannot be changed without disassembling the entire rear end. The backlash (distance between ring and pinion gear) is adjusted by shimming the sides of the ring gear carrier.

It would be best to have a professional check the gear pattern and make adjustments for you if it is necessary.

 

[Synyster06Gates]

Well damn... I changed the pinion seal and just set it back to where I had it marked. I guess I'll have to have someone look at it sooner or later. Appreciate it!

 

[Wildman113]

Well damn... I changed the pinion seal and just set it back to where I had it marked. I guess I'll have to have someone look at it sooner or later. Appreciate it!

That could be part of the problem actually.

If you only set it back to the mark you made, then you may not have preloaded the bearings enough, since the crush sleeve wasn't compressed any further.

When you use a mark for reference, always go slightly past that mark, so that you compress the crush sleeve slighly more which guarantees that you have taken up all slack between the bearings and have exceeded the previous preload amount at least slightly.

 

[006]

Also, whatever you do, do not use royal purple.

 

[notorious p.i.g]

I guess I'll have to get mine checked out too. My 03 gt and my 01 cobra both had that noise coming from the rear end, but our 05 gt never did so I always just assumed it was normal for the new edges.

 

[snakeraper11b]

I guess I'll have to get mine checked out too. My 03 gt and my 01 cobra both had that noise coming from the rear end, but our 05 gt never did so I always just assumed it was normal for the new edges.

Its not "normal" in any car. Either a bad install or cheap quality gears. Hence why you should on buy ford gears and make sure the shop is on point with pinion installs.

 

[Roots-type]

Also, whatever you do, do not use royal purple.

Whys that?

 

[soccerman002]

Also, whatever you do, do not use royal purple.

Never heard that before - their rear end gear oil is suppose to be a great product.

 

[Darkc0bra]

Also, whatever you do, do not use royal purple.

Never heard that before - their rear end gear oil is suppose to be a great product.

I have been running royal purple in the rear end of my cobra now for 2 years without any issues or whining. I'm not a fan of there Motor Oil but there gear oil is great.

 

[tistan]

4.10s are noisy gears. I have a set of ford racing gears in both my cars and they both whine. Both were setup by a guy I use that is very meticulous with his work and has 30+years experience building rears and transmissions. He said my whine isn't that bad. If i want to hear some loud whine get some motive gears. He won't install motive gears anymore because they all whine and too many people bitched about it. He said that in the last 10 years quality of ford racing gears has really fallen off too.

 

[01yellercobra]

Some of Ford's gear sets are now made by Motive.

 

[006]

Whys that?

Example:

Royal Purple – not a fan... - The Mustang Source - Ford Mustang Forums

Test results of their gear oil show them having the viscocity properties of water after as little as 500 miles. Their oil burns up.

http://www.925lube.com/AMSOIL_Onlin...es/A Study of Automotive Gear Lubes_20124.pdf

Bob is the oil guy (independent test results).

 

[Darkc0bra]

Example:

Royal Purple – not a fan... - The Mustang Source - Ford Mustang Forums

Test results of their gear oil show them having the viscocity properties of water after as little as 500 miles. Their oil burns up.

http://www.925lube.com/AMSOIL_Onlin...es/A Study of Automotive Gear Lubes_20124.pdf

Bob is the oil guy (independent test results).

That is crazy. All my buddies that have don't gear swaps, including myself, have been using that Royal Purple Gear Oil for a number of years now and haven't had any problems with whine or break down. It must just be the luck of the draw according to this :shrug:

 

[Gallows]

4.10s are noisy gears. I have a set of ford racing gears in both my cars and they both whine. Both were setup by a guy I use that is very meticulous with his work and has 30+years experience building rears and transmissions. He said my whine isn't that bad. If i want to hear some loud whine get some motive gears. He won't install motive gears anymore because they all whine and too many people bitched about it. He said that in the last 10 years quality of ford racing gears has really fallen off too.

My 4:10's were quiet the six years I ran them. My "new" IRS however has a very noisy set of 4:56's. Does FRPP make any of their own gears or do they all come from Motive?