leaking 14 bolt ff - The 1947 - Present Chevrolet & GMC Truck Message Board Network

85raiderburban · 02-06-2021, 08:17 PM

i havent drained the gear oil ever since ive owned the truck, will do so soon. What fluid should I use? 1980 G80 14 bolt FF and is there any type of sealant i can use instead of pulling the axle apart?

farmall · 02-06-2021, 08:42 PM

Lots of good info here.

http://www.billavista.com/tech/Artic...tup/index.html

**Getter-Done** · 02-06-2021, 10:22 PM

The first thing I would check,
Would be,
Those bolts holding the pinion in the housing.
They may be loose causing it to seep through the shims.

Also about the type of oil,
I would pull the cover to see if by a slim chance that
It may have a posi-traction unit in it.

If not there is a few choices.

Food for thought: found on this site in the link below.

Link: https://lugnut4x4.com/axles/best-14-...%20fill%20hole.

Why Use 75W-140 Gear Oil?
75W-140 gear oil is a good option for a wide range of temperatures. Unlike 80W-90 or 75W-90, 75W-140 offers protection at both colder temps (75) AND fairly high temps (140). While gear oil shouldn’t spend a lot of time at very high temperatures, it’s good to have protection in those scenarios. Likewise, you want protection at the lowest temperature possible for those few minutes when everything is still cold after start-up.

The downside to using 75W-140 gear oil is the cost. It’s about twice as expensive as conventional 80W-90, and maybe 30% more than conventional 85W-140 gear oil.

Still, the absolute cost difference is typically less than $20. For $20, it’s kind of a no-brainer.

.

**kwmech** · 02-06-2021, 10:28 PM

That is one of the easiest leaks to fix on a 14b. Remove the driveshaft--then the 6 bolts. Clean surfaces and the shims. Very thin application of an ultra silicone on surfaces and bolt back together. Bolts torque to about 50-55. G80 diff is the gov-loc and should only require the 75/90 gl-5 rated oil. A tube or 2 of modifier wouldn't hurt

02-06-2021, 08:17 PM	#1
85raiderburban Registered User Join Date: Nov 2014 Location: between AZ & NV Posts: 67	leaking 14 bolt ff i havent drained the gear oil ever since ive owned the truck, will do so soon. What fluid should I use? 1980 G80 14 bolt FF and is there any type of sealant i can use instead of pulling the axle apart? Attached Images __________________ UNDER CONSTRUCTION '80 Suburban C20 (C6P) (Silverado) - '68 472 (Edelbrock 1813, PH8026 LT's, H pipe) / '91 4L80 (manual shift,vac modulator, 350 converter) / 14B FF 3.21 G80 34' s/ '96 GMT400 interior

02-06-2021, 08:42 PM	#2
farmall Registered User Join Date: Jun 2011 Location: Central OR Posts: 728	Re: leaking 14 bolt ff Lots of good info here. http://www.billavista.com/tech/Artic...tup/index.html __________________ 1955 GMC 250 8 Flatbed 1971 C30 157" 350 4spd 10' Flatbed 81 GMC K30 CnC 9' Flatbed 454 T400 89 GMC Jimmy Stock https://67-72chevytrucks.com/vboard/...d.php?t=810958 71 LT1 Convertible, 72 Coupe 69 CJ5, 75 CJ6, 67 M715, 72 M35A2 Bobbed, 95 XLC2

02-06-2021, 10:22 PM	#3
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 8,413	Re: leaking 14 bolt ff The first thing I would check, Would be, Those bolts holding the pinion in the housing. They may be loose causing it to seep through the shims. Also about the type of oil, I would pull the cover to see if by a slim chance that It may have a posi-traction unit in it. If not there is a few choices. Food for thought: found on this site in the link below. Link: https://lugnut4x4.com/axles/best-14-...%20fill%20hole. Why Use 75W-140 Gear Oil? 75W-140 gear oil is a good option for a wide range of temperatures. Unlike 80W-90 or 75W-90, 75W-140 offers protection at both colder temps (75) AND fairly high temps (140). While gear oil shouldn’t spend a lot of time at very high temperatures, it’s good to have protection in those scenarios. Likewise, you want protection at the lowest temperature possible for those few minutes when everything is still cold after start-up. The downside to using 75W-140 gear oil is the cost. It’s about twice as expensive as conventional 80W-90, and maybe 30% more than conventional 85W-140 gear oil. Still, the absolute cost difference is typically less than $20. For $20, it’s kind of a no-brainer. . __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build

02-06-2021, 10:28 PM	#4
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,631	Re: leaking 14 bolt ff That is one of the easiest leaks to fix on a 14b. Remove the driveshaft--then the 6 bolts. Clean surfaces and the shims. Very thin application of an ultra silicone on surfaces and bolt back together. Bolts torque to about 50-55. G80 diff is the gov-loc and should only require the 75/90 gl-5 rated oil. A tube or 2 of modifier wouldn't hurt



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