The Ford Barn

twostickmutt · 02-15-2016, 07:58 AM

what is a good way to flush trans and rear on the 39. i'm going to change the oil in both and they probably need a little cleaning. they are still in a running car and what weight gear oil is recommended ? thanks !

Macdozer · 02-15-2016, 11:20 AM

I have to do the same with my rear end. I was thinking of draining it and then filling it with kerosene and letting it sit a day or two then draining and refilling.
Not sure on what type of oil to refill it with, hopefully someone will jump in and let us know.

19Fordy · 02-15-2016, 11:48 AM

The owners manual says the following is used for both transmission and rear end:
"Drain, flush and refill: with MILD EXTREME PRESSURE GEAR OIL. SAE 90 IN WINTER. SAE 140 IN SUMMER." Here's some gear oil info.
https://www.fordbarn.com/forum/showth...oil+banjo+rear

JSeery · 02-15-2016, 11:51 AM

In the transmission you need to be sure that the gear oil you use is "yellow" metal compatible. In the past this required GL-4 or lower, but some GL-5 gear oils now claim compatibility. If it was me I would stick with GL-4. The rear axle does not contain "yellow" metal so GL-4 vs GL-5 is not an issue.

"When someone tells you that their GL-5 oil covers GL-4, remember they are correct as far as EP protection, but that is only half answer. When they say their sulfur/phosphorous additive will not corrode the yellow metals, they are also correct, but if there are enough protection to meet GL-5 requirement, meanwhile they will slowly peel away your brass synchronizers in the manual transmission.
Just remember that API GL-4 and GL-5 are gear oil ratings, not transmission oil ratings. Transmissions have gears and synchronizers which seemingly conflicting requirements must be met differently.
A normal GL-4 gear oil with any given viscosity has about 1/2 level of sulfur/phosphorous additive that would be in the GL-5 product, so the bond is not as strong, and therefore can be peeled off without peeling a layer of brass (or less brass). This means that the GL-4 product provides a little less extreme pressure protection, so in the differential of a high powered car, it would not be the ideal product in the differential. To understand this need we should be aware of the fact that the differential is where the final torque is applied to the wheels.
When we use a GL-5 product in a transmission that requires GL-4, we normally find 2 to 4 times as much copper in the used oil as we would with a GL-4 product Eventually the synchronizers wear to the point that they no longer make contact with the other half of the cone, bottoming out before stopping the opposing gear."

twostickmutt · 02-15-2016, 12:29 PM

thanks for the replies !

moefuzz · 02-15-2016, 12:36 PM

Sponsored Links (Register now to hide all advertisements)

I agree on flushing with Kerosene or even cheaper Diesel fuel.
Or my favorite is a 50/50 mixture of both (works excellent on old seized blocks/pistons)

.

Admiral · 02-15-2016, 12:37 PM

If you suspect the transmission is really grungy inside (after draining the lube) you might consider pulling the floorboards and tunnel cover to gain access to the lid. Once removed, you'll have a bird's eye view of what's going on in there. Doing this would also make cleaning a severe mess up a lot easier. Of course, this might only be necessary if the oil came out like tar or was full of gunk.

moefuzz · 02-15-2016, 01:06 PM

Put a magnate in your oil drain pan and swish your oil once drained.
It's always interesting to see what turns up on the magnate.

...Don't be surprised if you find that your syncro mesh gets lazy after removing a sludgy mess.

Kinda reminds me of a guy who never once changed the oil in his brand new Cadillac (1960's), he just kept adding oil when needed.

When the second owner acquired the 65,000 Coupe De Ville, he changed the oil and threw a rod bearing,
And it wasn't ju$t any rod bearing,
It wa$ a Cadillac Rod Bearing..

.

twostickmutt · 02-15-2016, 01:13 PM

Quote:

Originally Posted by moefuzz

I agree on flushing with Kerosene or even cheaper Diesel fuel.
Or my favorite is a 50/50 mixture of both (works excellent on old seized blocks/pistons)

.

i wonder if it would hurt to jack one wheel up start the motor in first gear and just let it do a slow spin for a minute or two and then let it drain extra good ?

moefuzz · 02-15-2016, 01:22 PM

It would not be a problem draining the stuff, filling with diesel/kerosene
and rotating the tires as per your engine and safely hosted vehicle.

The diesel kerosene mix will help flush the entire system if allowed to run for a few minutes under light load.

twostickmutt · 02-15-2016, 01:26 PM

sounds good. i'll give it a whirl. thanks.

Talkwrench · 02-15-2016, 07:17 PM

How bad do you think it is? Personally I would buy enough mild EP - GL4 , they don't take much. Put it in run it round for a week or one long good hard run for a day , drain it and refill and a way you go.

rotorwrench · 02-15-2016, 07:44 PM

Put some straight grade SAE 30 (or higher if you can find it) motor oil in there and drive it around for a while. The detergents in the oil will loosen most of the crud and drain it out ASAP after last drive.

Most FBOs at airports carry straight 100 grade SAE 50 motor oil but I would run that all the time and not waist it for a flush. SAE 50 motor oil is a direct cross over for SAE 90 gear lube as far as viscosity goes. There is no EP in it as long as you don't purchase anything with plus or + on the label. The plus has TCP for cam follower anti scuff additive in it.

moefuzz · 02-15-2016, 08:51 PM

That's what the diesel fuel does, it has much stronger detergents than engine oil.

Drbrown · 02-15-2016, 11:45 PM

Concerns: If your axle and/or drive tube seals are in poor condition, whatever you use for "flushing" may contaminate your wheel bearing grease etc. or even promote new leakage. Notice that the manufacturers stopped including "flushing" in later years, granted PERHAPS due to newer gear oils.

Personally, as long as I change it frequently enough and what drains-out looks reasonably clean, I don't flush. I use StaLube GL-4 90 in my tranny and SAE 140 in my BW-OD and rear end.

Tom/SC · 02-16-2016, 01:20 PM

Please consider Browns advice. I have not yet seen a trans or rear axle that was sludged up. you just might damage more than you would help by adding cleaning agents. The advice to perhaps run some 30 wt. in these for a short time and then drain and add proper lube is good. When you do anything to remove existing lube coating from the gears, you risk metal to metal wear and i dont think you want to risk that. When I was a teenager I bought a"used" 40 Ford engine to put in my 40. Some old putz told me to "clean" the engine with a Quart of Esso engine clean and kerosene. The engine did not smoke before I did this but it did smoke always after this. Fill both units with proper lube and drive it. It will probably outlast all of us!

twostickmutt · 02-16-2016, 02:36 PM

i haven't done anything yet so i'm just gonna run it around when the weather up here gets better,get the gear oil good and warm and pull the plugs and see what comes out. i may not be bad off so maybe i can just refill the trans and rear even if i have to do it a couple of times.

Drbrown · 02-16-2016, 06:34 PM

Tom/SC .... Ha ! Kerosene, the miracle drug. I knew an old timer in the '50s who said he flushed engines with a quart of kerosene and 10w oil. I never did it and certainly wouldn't have wanted to run an engine long on that. I can imagine what could slide-down into the oil pan from the valve gallery.

I worked in a service station in the '50s and there was a Ford Owner who came in for oil & lube every 1000 miles. He always sprayed the underside of his car with kerosene and light oil every 1000 miles. Last I knew the car never rusted but I bet it was a 1000 lbs heavier after all the road dirt combined with that mix, and if it ever caught fire it would have been a sight to see.

rotorwrench · 02-16-2016, 06:58 PM

All I do with kerosene is run it in the turbine helicopters. Jet A is mostly kerosene with a small amount of what most people would call white gas or naptha base gasolene. These are fuels & solvents. Kerosene has some lubricating qualities such as lubricating the fuel pump that moves it but that is about it. Solvents have a tendency to open up more problems than they solve unless you are cleaning parts and blowing them dry with compressed air. They can keep the lubricant from adhering to the bearings, races, and gears for a while if still in the pores of the metal. This can do more damage than good.

Tom/SC · 02-16-2016, 11:19 PM

DRBrown, the 40 I bought in 1956 had a manifold heater which worked. My Dad had a service station that I hung around in. Another old Putz about the age I am now said" boy take that thing off, it will put you to sleep," so I threw it in the garbage! Live and learn! Now they are very rare. I still have the 40 Ford.

02-15-2016, 07:58 AM	#1
twostickmutt Senior Member Join Date: Oct 2015 Location: hinsdale,ma Posts: 200	flushing trans and rear end what is a good way to flush trans and rear on the 39. i'm going to change the oil in both and they probably need a little cleaning. they are still in a running car and what weight gear oil is recommended ? thanks !

02-15-2016, 11:20 AM	#2
Macdozer Senior Member Join Date: Jun 2012 Location: Central NH Posts: 192	Re: flushing trans and rear end I have to do the same with my rear end. I was thinking of draining it and then filling it with kerosene and letting it sit a day or two then draining and refilling. Not sure on what type of oil to refill it with, hopefully someone will jump in and let us know.

02-15-2016, 11:48 AM	#3
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,921	Re: flushing trans and rear end The owners manual says the following is used for both transmission and rear end: "Drain, flush and refill: with MILD EXTREME PRESSURE GEAR OIL. SAE 90 IN WINTER. SAE 140 IN SUMMER." Here's some gear oil info. https://www.fordbarn.com/forum/showth...oil+banjo+rear Last edited by 19Fordy; 02-15-2016 at 11:56 AM.

02-15-2016, 11:51 AM	#4
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: flushing trans and rear end In the transmission you need to be sure that the gear oil you use is "yellow" metal compatible. In the past this required GL-4 or lower, but some GL-5 gear oils now claim compatibility. If it was me I would stick with GL-4. The rear axle does not contain "yellow" metal so GL-4 vs GL-5 is not an issue. "When someone tells you that their GL-5 oil covers GL-4, remember they are correct as far as EP protection, but that is only half answer. When they say their sulfur/phosphorous additive will not corrode the yellow metals, they are also correct, but if there are enough protection to meet GL-5 requirement, meanwhile they will slowly peel away your brass synchronizers in the manual transmission. Just remember that API GL-4 and GL-5 are gear oil ratings, not transmission oil ratings. Transmissions have gears and synchronizers which seemingly conflicting requirements must be met differently. A normal GL-4 gear oil with any given viscosity has about 1/2 level of sulfur/phosphorous additive that would be in the GL-5 product, so the bond is not as strong, and therefore can be peeled off without peeling a layer of brass (or less brass). This means that the GL-4 product provides a little less extreme pressure protection, so in the differential of a high powered car, it would not be the ideal product in the differential. To understand this need we should be aware of the fact that the differential is where the final torque is applied to the wheels. When we use a GL-5 product in a transmission that requires GL-4, we normally find 2 to 4 times as much copper in the used oil as we would with a GL-4 product Eventually the synchronizers wear to the point that they no longer make contact with the other half of the cone, bottoming out before stopping the opposing gear." Last edited by JSeery; 02-15-2016 at 12:11 PM.

02-15-2016, 12:29 PM	#5
twostickmutt Senior Member Join Date: Oct 2015 Location: hinsdale,ma Posts: 200	Re: flushing trans and rear end thanks for the replies !

02-15-2016, 12:36 PM	#6
moefuzz Senior Member Join Date: May 2010 Location: Under A Clean V8 Posts: 228	Re: flushing trans and rear end Sponsored Links (Register now to hide all advertisements) I agree on flushing with Kerosene or even cheaper Diesel fuel. Or my favorite is a 50/50 mixture of both (works excellent on old seized blocks/pistons) .

02-15-2016, 12:37 PM	#7
Admiral Senior Member Join Date: Jul 2011 Location: Oakland County, Michigan Posts: 562	Re: flushing trans and rear end If you suspect the transmission is really grungy inside (after draining the lube) you might consider pulling the floorboards and tunnel cover to gain access to the lid. Once removed, you'll have a bird's eye view of what's going on in there. Doing this would also make cleaning a severe mess up a lot easier. Of course, this might only be necessary if the oil came out like tar or was full of gunk.

02-15-2016, 01:06 PM	#8
moefuzz Senior Member Join Date: May 2010 Location: Under A Clean V8 Posts: 228	Re: flushing trans and rear end Put a magnate in your oil drain pan and swish your oil once drained. It's always interesting to see what turns up on the magnate. ...Don't be surprised if you find that your syncro mesh gets lazy after removing a sludgy mess. Kinda reminds me of a guy who never once changed the oil in his brand new Cadillac (1960's), he just kept adding oil when needed. When the second owner acquired the 65,000 Coupe De Ville, he changed the oil and threw a rod bearing, And it wasn't ju$t any rod bearing, It wa$ a Cadillac Rod Bearing.. .

02-15-2016, 01:22 PM	#10
moefuzz Senior Member Join Date: May 2010 Location: Under A Clean V8 Posts: 228	Re: flushing trans and rear end It would not be a problem draining the stuff, filling with diesel/kerosene and rotating the tires as per your engine and safely hosted vehicle. The diesel kerosene mix will help flush the entire system if allowed to run for a few minutes under light load.

02-15-2016, 01:26 PM	#11
twostickmutt Senior Member Join Date: Oct 2015 Location: hinsdale,ma Posts: 200	Re: flushing trans and rear end sounds good. i'll give it a whirl. thanks.

02-15-2016, 07:17 PM	#12
Talkwrench Senior Member Join Date: Aug 2012 Location: Perth, Western Australia Posts: 2,687	Re: flushing trans and rear end How bad do you think it is? Personally I would buy enough mild EP - GL4 , they don't take much. Put it in run it round for a week or one long good hard run for a day , drain it and refill and a way you go. __________________ *"Came too close to dying to stop living now!"*

02-15-2016, 07:44 PM	#13
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,422	Re: flushing trans and rear end Put some straight grade SAE 30 (or higher if you can find it) motor oil in there and drive it around for a while. The detergents in the oil will loosen most of the crud and drain it out ASAP after last drive. Most FBOs at airports carry straight 100 grade SAE 50 motor oil but I would run that all the time and not waist it for a flush. SAE 50 motor oil is a direct cross over for SAE 90 gear lube as far as viscosity goes. There is no EP in it as long as you don't purchase anything with plus or + on the label. The plus has TCP for cam follower anti scuff additive in it.

02-15-2016, 08:51 PM	#14
moefuzz Senior Member Join Date: May 2010 Location: Under A Clean V8 Posts: 228	Re: flushing trans and rear end That's what the diesel fuel does, it has much stronger detergents than engine oil.

02-15-2016, 11:45 PM	#15
Drbrown Senior Member Join Date: Oct 2013 Location: Glens Falls NY Posts: 1,267	Re: flushing trans and rear end Concerns: If your axle and/or drive tube seals are in poor condition, whatever you use for "flushing" may contaminate your wheel bearing grease etc. or even promote new leakage. Notice that the manufacturers stopped including "flushing" in later years, granted PERHAPS due to newer gear oils. Personally, as long as I change it frequently enough and what drains-out looks reasonably clean, I don't flush. I use StaLube GL-4 90 in my tranny and SAE 140 in my BW-OD and rear end. Last edited by Drbrown; 02-15-2016 at 11:51 PM.

02-16-2016, 01:20 PM	#16
Tom/SC Senior Member Join Date: May 2010 Location: Blythewood, SC Posts: 242	Re: flushing trans and rear end Please consider Browns advice. I have not yet seen a trans or rear axle that was sludged up. you just might damage more than you would help by adding cleaning agents. The advice to perhaps run some 30 wt. in these for a short time and then drain and add proper lube is good. When you do anything to remove existing lube coating from the gears, you risk metal to metal wear and i dont think you want to risk that. When I was a teenager I bought a"used" 40 Ford engine to put in my 40. Some old putz told me to "clean" the engine with a Quart of Esso engine clean and kerosene. The engine did not smoke before I did this but it did smoke always after this. Fill both units with proper lube and drive it. It will probably outlast all of us!

02-16-2016, 02:36 PM	#17
twostickmutt Senior Member Join Date: Oct 2015 Location: hinsdale,ma Posts: 200	Re: flushing trans and rear end i haven't done anything yet so i'm just gonna run it around when the weather up here gets better,get the gear oil good and warm and pull the plugs and see what comes out. i may not be bad off so maybe i can just refill the trans and rear even if i have to do it a couple of times.

02-16-2016, 06:34 PM	#18
Drbrown Senior Member Join Date: Oct 2013 Location: Glens Falls NY Posts: 1,267	Re: flushing trans and rear end Tom/SC .... Ha ! Kerosene, the miracle drug. I knew an old timer in the '50s who said he flushed engines with a quart of kerosene and 10w oil. I never did it and certainly wouldn't have wanted to run an engine long on that. I can imagine what could slide-down into the oil pan from the valve gallery. I worked in a service station in the '50s and there was a Ford Owner who came in for oil & lube every 1000 miles. He always sprayed the underside of his car with kerosene and light oil every 1000 miles. Last I knew the car never rusted but I bet it was a 1000 lbs heavier after all the road dirt combined with that mix, and if it ever caught fire it would have been a sight to see.

02-16-2016, 06:58 PM	#19
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,422	Re: flushing trans and rear end All I do with kerosene is run it in the turbine helicopters. Jet A is mostly kerosene with a small amount of what most people would call white gas or naptha base gasolene. These are fuels & solvents. Kerosene has some lubricating qualities such as lubricating the fuel pump that moves it but that is about it. Solvents have a tendency to open up more problems than they solve unless you are cleaning parts and blowing them dry with compressed air. They can keep the lubricant from adhering to the bearings, races, and gears for a while if still in the pores of the metal. This can do more damage than good.

02-16-2016, 11:19 PM	#20
Tom/SC Senior Member Join Date: May 2010 Location: Blythewood, SC Posts: 242	Re: flushing trans and rear end DRBrown, the 40 I bought in 1956 had a manifold heater which worked. My Dad had a service station that I hung around in. Another old Putz about the age I am now said" boy take that thing off, it will put you to sleep," so I threw it in the garbage! Live and learn! Now they are very rare. I still have the 40 Ford.