The Ford Barn

4t8v8 · 02-24-2018, 12:01 PM

Have a lot of conflicting answers on what is the correct oil. Does anyone know the answer?

JSeery · 02-24-2018, 12:07 PM

The world class switched to ATF because of the synchros, I believe the nwc would still use the original OEM recommendations. Any reason you don't what to follow the original reccomendations?

4t8v8 · 02-24-2018, 01:04 PM

I would like to follow the OEM recommendations but can't seem to find them. Ive looked all over the internet and tried contacting Tremec to no avail. Just wondering what other folks are using. I'm using Royal Purple Gear Max in it now but having trouble with leaks. It has a little over 3000 miles on it since rebuild.

JSeery · 02-24-2018, 04:41 PM

Well, what I'm seeing is Synchromesh 12345577. Think this stuff is expensive and hard to come by. Let me do some checking (I'm a World Class guy which uses Dextron III).

Update, from Flat Ernie post:

All NWC T-5 use 70WT Gear Oil or Redline MTL.
ALL WC T-5 use ATF.
ALL subsequent manuals tell us to use ATF in ALL T-5. So, what's the story? The OEMs originally used a 70WT gear oil in the early NWC transmissions. As the automakers were focusing on NVH and MPG, the switch to ATF was made and this coincided with the WC upgrade. It is generally safe to use in the early T-5 as well. However, do NOT use gear oil in a WC T-5 though - it will ruin the blocker rings/synchros. Use a quality synthetic oil (regardless of which type you need to use) & change it frequently (every 15-20K). Fill to the fill plug; about 5-1/2 pints or 2-1/2 quarts.

If you are having a leakage issue you are most likely going to have to find where it is leaking and fix it.

Ronnieroadster · 02-24-2018, 04:53 PM

Quote:

Originally Posted by 4t8v8

I would like to follow the OEM recommendations but can't seem to find them. Ive looked all over the internet and tried contacting Tremec to no avail. Just wondering what other folks are using. I'm using Royal Purple Gear Max in it now but having trouble with leaks. It has a little over 3000 miles on it since rebuild.

I switched to ATF synthetic years ago gave up on any of the recommended lubes especially when it required a GM only lube. So far after two cross country round trips and another 20,000 miles or so all is fine. As far as leaks changing to ATF will not eliminate that problem.
Ronnieroadster

4t8v8 · 02-24-2018, 06:06 PM

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The Max Gear is 75W so ATF would leak worse I'm sure.
Thanks for the responses. Much appreciated.

JSeery · 02-24-2018, 06:16 PM

75W gear lube is in the viscosity range of 15W motor oil. Not what you want to hear, but don't think attempting to run a thicker lubricant is going to help. Bad news is you are going to have to fix the leaks. Who did the rebuild and why is it leaking? I have rebuilt a number of T5 and never had a leak issue, I would guess something is not correct somewhere.

V8COOPMAN · 02-24-2018, 07:04 PM

Quote:

Originally Posted by JSeery

75W gear lube is in the viscosity range of 15W motor oil. Not what you want to hear, but don't think attempting to run a thicker lubricant is going to help. Bad news is you are going to have to fix the leaks. Who did the rebuild and why is it leaking? I have rebuilt a number of T5 and never had a leak issue, I would guess something is not correct somewhere.

JSeery is correct...T5s are NOT leak prone. It is possible to use too much sealant on the mating surfaces where the tail shaft housing meets the rear of the main case, leading to leaks. That sealant which is used in place of any gasket should only be applied in a skinny bead. DD

Ken/Alabama · 02-24-2018, 09:11 PM

I have a non world class S-10 5 speed in my 40 and it uses ATF.

donald1950 · 02-24-2018, 09:19 PM

i used Mobil 1 Synthetic ATF in my T-5s

4t8v8 · 02-24-2018, 11:45 PM

I've rebuilt a few T5's also and never had a leak.That is why it surprised me. It finally got warm enough to get out and crawl under it. My rear main doesn't leak so I suspected the tranny. Found the leak. It was the oil pressure sending unit. Easy fix. Thanks again for the help. Learned a little about oil viscosity.

JSeery · 02-25-2018, 12:11 AM

That's good! Easy fix.

02-24-2018, 12:01 PM	#1
4t8v8 Senior Member Join Date: Nov 2011 Location: NW Arkansas Posts: 524	NWC T5 Oil Have a lot of conflicting answers on what is the correct oil. Does anyone know the answer?

02-24-2018, 12:07 PM	#2
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: NWC T5 Oil The world class switched to ATF because of the synchros, I believe the nwc would still use the original OEM recommendations. Any reason you don't what to follow the original reccomendations?

02-24-2018, 01:04 PM	#3
4t8v8 Senior Member Join Date: Nov 2011 Location: NW Arkansas Posts: 524	Re: NWC T5 Oil I would like to follow the OEM recommendations but can't seem to find them. Ive looked all over the internet and tried contacting Tremec to no avail. Just wondering what other folks are using. I'm using Royal Purple Gear Max in it now but having trouble with leaks. It has a little over 3000 miles on it since rebuild.

02-24-2018, 04:41 PM	#4
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: NWC T5 Oil Well, what I'm seeing is Synchromesh 12345577. Think this stuff is expensive and hard to come by. Let me do some checking (I'm a World Class guy which uses Dextron III). Update, from Flat Ernie post: All NWC T-5 use 70WT Gear Oil or Redline MTL. ALL WC T-5 use ATF. ALL subsequent manuals tell us to use ATF in ALL T-5. So, what's the story? The OEMs originally used a 70WT gear oil in the early NWC transmissions. As the automakers were focusing on NVH and MPG, the switch to ATF was made and this coincided with the WC upgrade. It is generally safe to use in the early T-5 as well. However, do NOT use gear oil in a WC T-5 though - it will ruin the blocker rings/synchros. Use a quality synthetic oil (regardless of which type you need to use) & change it frequently (every 15-20K). Fill to the fill plug; about 5-1/2 pints or 2-1/2 quarts. If you are having a leakage issue you are most likely going to have to find where it is leaking and fix it. Last edited by JSeery; 02-24-2018 at 04:51 PM.

02-24-2018, 06:06 PM	#6
4t8v8 Senior Member Join Date: Nov 2011 Location: NW Arkansas Posts: 524	Re: NWC T5 Oil Sponsored Links (Register now to hide all advertisements) The Max Gear is 75W so ATF would leak worse I'm sure. Thanks for the responses. Much appreciated.

02-24-2018, 06:16 PM	#7
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: NWC T5 Oil 75W gear lube is in the viscosity range of 15W motor oil. Not what you want to hear, but don't think attempting to run a thicker lubricant is going to help. Bad news is you are going to have to fix the leaks. Who did the rebuild and why is it leaking? I have rebuilt a number of T5 and never had a leak issue, I would guess something is not correct somewhere. Last edited by JSeery; 02-24-2018 at 06:22 PM.

02-24-2018, 09:11 PM	#9
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,260	Re: NWC T5 Oil I have a non world class S-10 5 speed in my 40 and it uses ATF.

02-24-2018, 09:19 PM	#10
donald1950 Senior Member Join Date: May 2010 Location: san antonio, texas Posts: 461	Re: NWC T5 Oil i used Mobil 1 Synthetic ATF in my T-5s

02-24-2018, 11:45 PM	#11
4t8v8 Senior Member Join Date: Nov 2011 Location: NW Arkansas Posts: 524	Re: NWC T5 Oil I've rebuilt a few T5's also and never had a leak.That is why it surprised me. It finally got warm enough to get out and crawl under it. My rear main doesn't leak so I suspected the tranny. Found the leak. It was the oil pressure sending unit. Easy fix. Thanks again for the help. Learned a little about oil viscosity.

02-25-2018, 12:11 AM	#12
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: NWC T5 Oil That's good! Easy fix.