The Ford Barn

fortyonerag · 06-18-2018, 05:35 AM

Driving home sedately in my bone stock 41 SD convert. At about 45, the gearbox erupted into a terrible gnashing crashing sound.

It got my full attention! After I depressed the clutch and shoved it back into gear the cacophony subsided. Happened twice on the 30 min drive home.

I have cars jump out of gear before, but usually into neutral. Is this noise normal?

A check of the gearbox oil showed nothing that would register to my limited knowledge, although the oil might have been a little low (failed the pinkie test).

I have replaced the oil. Do I have a gearbox rebuild in my future, or am I overreacting?

Charlie ny · 06-18-2018, 07:08 AM

Meticulously examine your linkage.....rubber/brass bushings......neutral position must
be clean blah blah. Sounds like maybe 1st and rev slider going it's own way which
might be linkage.
Charlie ny

alanwoodieman · 06-18-2018, 07:14 AM

did you lube the universal joint? had something like this happen to me and that is what it was. any metals at all in the drained out doping?

fortyonerag · 06-18-2018, 09:01 PM

Charlie, thanks for the tip. I'll have a close look at the linkages

Alan, I had the whole back end out recently for a diff rebuild. I can't recall what I did with the uni

. I'll check it out also.

The gearbox drain out had a kinda pearly sheen but no metal fragments as such.

Many thanks for the replies gents.

alanwoodieman · 06-18-2018, 10:16 PM

mix 1/2 half synthetic trans fluid 85W140 and 1/2 synthetic grease-stir to the consistency of mustard--use the tube from the grease, fill it up and use an air grease gun and pump the fitting on the u-joint cover-use all of the "goop" don't let anyone tell you it will not get to the u joint, it will and I can prove it!

Tinker · 06-18-2018, 11:14 PM

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might have chipped a tooth and it ran through. pull the tower and check the gears.

fortyonerag · 06-21-2018, 04:29 AM

The linkages are are smooth and clean however I found a spot where there may have been a bit of interference/chafing. There are heim joints at the gearbox ends of the selector rods and one of the grease nipples may have been interfering and is now (hopefully) remedied.

A couple of queries:

The gear selector rods are retained on the gearbox selector arms by cotter pins. The shaft taking the cotter pin (01A-7331) is able to rotate on the 1st & rev lever selector (21A-7285). Is this correct?

I refilled the gearbox the other day and have not yet driven it but the selector shafts are already weeping. Is it correct to assume they are bad and need replacing.

Apols for the long winded email and dodgy descriptions, your assistance is greatly appreciated.

George/Maine · 06-21-2018, 10:12 AM

I guess this could happen again.
I bought a 46 ford and the trans was rebuilt and the owner paid plenty .
I was having shifting trouble I 1st and rev.
It jumped out of 1st and chipped a tooth.
Then it took out the cluster.
I took it down and found they left out the bolt that holds the uj on.
If take the cover off and use the 2 nd gear that is held solid on shaft and pry back and forth you don,t want like 1/4" movement.
Leaking is very bad on bearing and oiling uj.

06-18-2018, 05:35 AM	#1
fortyonerag Senior Member Join Date: Sep 2016 Location: Melbourne Australia Posts: 540	Gaaaa! My 41 gearbox sounds like its full of rocks! Driving home sedately in my bone stock 41 SD convert. At about 45, the gearbox erupted into a terrible gnashing crashing sound. It got my full attention! After I depressed the clutch and shoved it back into gear the cacophony subsided. Happened twice on the 30 min drive home. I have cars jump out of gear before, but usually into neutral. Is this noise normal? A check of the gearbox oil showed nothing that would register to my limited knowledge, although the oil might have been a little low (failed the pinkie test). I have replaced the oil. Do I have a gearbox rebuild in my future, or am I overreacting?

06-18-2018, 07:08 AM	#2
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Gaaaa! My 41 gearbox sounds like its full of rocks! Meticulously examine your linkage.....rubber/brass bushings......neutral position must be clean blah blah. Sounds like maybe 1st and rev slider going it's own way which might be linkage. Charlie ny

06-18-2018, 07:14 AM	#3
alanwoodieman Senior Member Join Date: May 2010 Location: upstate SC Posts: 2,963	Re: Gaaaa! My 41 gearbox sounds like its full of rocks! did you lube the universal joint? had something like this happen to me and that is what it was. any metals at all in the drained out doping?

06-18-2018, 09:01 PM	#4
fortyonerag Senior Member Join Date: Sep 2016 Location: Melbourne Australia Posts: 540	Re: Gaaaa! My 41 gearbox sounds like its full of rocks! Charlie, thanks for the tip. I'll have a close look at the linkages Alan, I had the whole back end out recently for a diff rebuild. I can't recall what I did with the uni. I'll check it out also. The gearbox drain out had a kinda pearly sheen but no metal fragments as such. Many thanks for the replies gents.

06-18-2018, 10:16 PM	#5
alanwoodieman Senior Member Join Date: May 2010 Location: upstate SC Posts: 2,963	Re: Gaaaa! My 41 gearbox sounds like its full of rocks! mix 1/2 half synthetic trans fluid 85W140 and 1/2 synthetic grease-stir to the consistency of mustard--use the tube from the grease, fill it up and use an air grease gun and pump the fitting on the u-joint cover-use all of the "goop" don't let anyone tell you it will not get to the u joint, it will and I can prove it!

06-18-2018, 11:14 PM	#6
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Gaaaa! My 41 gearbox sounds like its full of rocks! Sponsored Links (Register now to hide all advertisements) might have chipped a tooth and it ran through. pull the tower and check the gears.

06-21-2018, 04:29 AM	#7
fortyonerag Senior Member Join Date: Sep 2016 Location: Melbourne Australia Posts: 540	Re: Gaaaa! My 41 gearbox sounds like its full of rocks! The linkages are are smooth and clean however I found a spot where there may have been a bit of interference/chafing. There are heim joints at the gearbox ends of the selector rods and one of the grease nipples may have been interfering and is now (hopefully) remedied. A couple of queries: The gear selector rods are retained on the gearbox selector arms by cotter pins. The shaft taking the cotter pin (01A-7331) is able to rotate on the 1st & rev lever selector (21A-7285). Is this correct? I refilled the gearbox the other day and have not yet driven it but the selector shafts are already weeping. Is it correct to assume they are bad and need replacing. Apols for the long winded email and dodgy descriptions, your assistance is greatly appreciated. Last edited by fortyonerag; 06-21-2018 at 04:42 AM.

06-21-2018, 10:12 AM	#8
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: Gaaaa! My 41 gearbox sounds like its full of rocks! I guess this could happen again. I bought a 46 ford and the trans was rebuilt and the owner paid plenty . I was having shifting trouble I 1st and rev. It jumped out of 1st and chipped a tooth. Then it took out the cluster. I took it down and found they left out the bolt that holds the uj on. If take the cover off and use the 2 nd gear that is held solid on shaft and pry back and forth you don,t want like 1/4" movement. Leaking is very bad on bearing and oiling uj.