72 F100 - Rear Differential Lube?

jlb · Post by **jlb** » Wed Jun 27, 2018 1:13 pm

What is the correct weight and should I use a certain brand? Pinion seal is leaking. So I thought I'd better check the level and its little low. I just want to top it off until I can have it done.

Please advise. Thank you in advance.

1972 F100 302v8
3speed. No idea if its a 9" or 8" rear.

Post by **Ranchero50** » Wed Jun 27, 2018 2:08 pm

Should be a 9" on all of the trucks. Block the wheels, knock it out of gear and check for looseness in the pinion shaft. Seals usually don't leak until the bearings get loose.

jlb · Post by **jlb** » Wed Jun 27, 2018 2:31 pm

Ranchero50 wrote:Should be a 9" on all of the trucks. Block the wheels, knock it out of gear and check for looseness in the pinion shaft. Seals usually don't leak until the bearings get loose.

I'll have to check. I know it drips on the floor in the garage. What kind of lube do you suggest to top it off.
Thank you.

cep62 · Post by **cep62** » Wed Jun 27, 2018 5:37 pm

This may not be an issue on a 2wd ,
but I've seen 4wd vent tubes get plugged and create a pinion leak.
clean out the vent and the leak stops.

Post by **Ranchero50** » Wed Jun 27, 2018 8:24 pm

jlb wrote:
Ranchero50 wrote:Should be a 9" on all of the trucks. Block the wheels, knock it out of gear and check for looseness in the pinion shaft. Seals usually don't leak until the bearings get loose.
I'll have to check. I know it drips on the floor in the garage. What kind of lube do you suggest to top it off.
Thank you.

I honestly don't remember what I put in, whatever the service manual recommended in a dino version.

jlb · Post by **jlb** » Wed Jun 27, 2018 8:54 pm

cep62 wrote:This may not be an issue on a 2wd ,
but I've seen 4wd vent tubes get plugged and create a pinion leak.
clean out the vent and the leak stops.

Thank you. I'll check that. I did notice today that the tube that connects to the vent was broken off.. .I'll have to get another tube to connect to the vent.

sargentrs · Post by **sargentrs** » Thu Jun 28, 2018 4:39 am

I've always used 90w gear oil in the squeeze bottles with the pointed tip.

jlb · Post by **jlb** » Thu Jun 28, 2018 7:22 am

sargentrs wrote:I've always used 90w gear oil in the squeeze bottles with the pointed tip.

Thank you

ezmerf · Post by **ezmerf** » Fri Aug 24, 2018 8:28 pm

I also used the 90 wgt that's supposed to mix with any.Later on I found on back of glove box door the transfer and stuff took a 50 wgt I'm sure it was gear oil.

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72 F100 - Rear Differential Lube?

72 F100 - Rear Differential Lube?

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