05-09-2023, 10:17 PM | #1 |
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1968 GMC Rear End
Hello...
I am going to be pulling the cover on my rear end to replace the gasket and fluid and have a few questions. 1. What weight gear oil is recommended? 2. What brand gear oil does everyone recommend? 3. How do I determine what gears I have? Thank you! |
05-09-2023, 10:29 PM | #2 |
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Re: 1968 GMC Rear End
GL-5 90 weight oil is okay for the older stuff.
Amsoil has good products. And the ratio is stamped in the ring gear.
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05-09-2023, 11:09 PM | #3 |
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Re: 1968 GMC Rear End
That being a Dana 44, there's a good chance you could have some 3.54 gears.
I've been using 80w-90 in my old axles and haven't noticed any issues. If you've got a limited slip, make sure you have either some additive on hand or use a gear oil that comes with the limited slip additive already mixed in
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06-03-2023, 08:34 PM | #4 |
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Re: 1968 GMC Rear End
Finally got some time. Open rear end with 3.54 gears. New gasket and fluid in.
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06-04-2023, 10:02 PM | #5 |
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Re: 1968 GMC Rear End
Always my recommendation to take it apart and look and change fluid. But I believe I see the Dana tag under the cover bolt at 11 o’clock? That would tell you as well. But you can’t always believe it… I have an 86 K30 with Dana 60 in front and it had the 3.73 tag under the bolt but a set of 4.10’s inside!
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07-09-2023, 09:02 PM | #6 |
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Re: 1968 GMC Rear End
I have a leak at the rear end after putting on the new cover gasket. The leak is not coming from the cover. I believe it is leaking where the driveshaft enters the rear end so I am going to replace the pinion seal. Any tips on doing this? Do I need a special tool to insert the new seal? Thanks ..
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07-09-2023, 10:39 PM | #7 |
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Re: 1968 GMC Rear End
The Dana axle doesn’t use a crush sleeve, so it is easier to get it exact when you put it back together since you can torque to spec. I would get a new pinion nut. You cannot use a seal installer because of the pinion (maybe a ball joint boot installer?) I just use a wide, flat hammer to go around the seal tapping it in.
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44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
07-20-2023, 05:32 PM | #8 |
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Re: 1968 GMC Rear End
Ok. What is the truck to getting pinion nut off? I don't have an impact. I tried using an 18 inch breaker bar with a 2 foot pipe added to it for leverage. It's not budging.
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07-20-2023, 07:01 PM | #9 | |
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Re: 1968 GMC Rear End
Quote:
I have a Dana 44 in my '56 Ford and I wanted to replace the pinion seal during some other resto work I was doing. I made a "pinion holding tool" that prevents the pinion from turning when applying torque. I'll post a pic. I made it myself with scrap I had laying around. After that I put a good 18" breaker bar(Proto) and used a hydraulic car jack to "lift/turn" the end of the breaker bar but the socket kept slowly coming off. So I had to jury rig a weird thing that basically bolted the socket to the bolt. I applied so much torque that the breaker bar looked like a banana. It was EXTREMELY tight. I've never experienced anything that tight before, other than maybe 50 year old lugs on a 2-ton truck. |
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07-21-2023, 08:59 AM | #10 |
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Re: 1968 GMC Rear End
When removing the pinion nut, should the transmission be in neutral? Should parking brake be on?
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07-23-2023, 03:13 PM | #11 |
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Re: 1968 GMC Rear End
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