slodat Posted September 10, 2009 Report Share Posted September 10, 2009 I have a '79 620 that I'm giving a once over prior to it assuming daily driver duties for my girlfriend. I pulled the rear wheels off today and found a bunch of muck everywhere. It is the gear oil from the rear end. I pulled the axles out and started cleaning everything up to reseal it. The inner seals were both installed with the flat side(with the rubber) facing inward (toward the third member). I have a factory service manual for the truck. The photos and narrative do not specify which way the seal should be installed. Needless to say, I'm picking up new seals tomorrow and would like to make sure I install them correctly. Anyone know for sure? Quote Link to comment
72wagun Posted September 10, 2009 Report Share Posted September 10, 2009 (edited) You're right, they are in backwards. Flat part should be out. The "groove" should be toward the 3rd member. Not an H190, but this pic shows the same idea. The brownish gold part is the flat side. Edited September 10, 2009 by 72wagun Quote Link to comment
slodat Posted September 10, 2009 Author Report Share Posted September 10, 2009 Thanks! That's what I thought. Mine were installed the opposite of that photo by someone.. Quote Link to comment
slodat Posted September 12, 2009 Author Report Share Posted September 12, 2009 Another question. I'm working on a '79. According to my '79 620 FSM it should have a 4.11 ratio. I have pulled the pinion flange to replace the pinion seal. The third member case is made of aluminum and the ring gear is stamped 35:8 which makes the ratio 4.375. The seal that the parts store gave me is too big. I looked at CSK's web site and it lists different 620 pinion seal part numbers for '72-'73 and '74-'79. I had thought the aluminum third members were from the early trucks and 510 wagons. Can anyone shed some light on what this thing might be? The rear axle has been apart for sure because the axle seals were installed backwards. Quote Link to comment
DISLEXICDIME Posted September 12, 2009 Report Share Posted September 12, 2009 well 30+ year old truck some one probably had to replace the rear end at one time Quote Link to comment
yello620 Posted September 12, 2009 Report Share Posted September 12, 2009 Another question. I'm working on a '79. According to my '79 620 FSM it should have a 4.11 ratio. I have pulled the pinion flange to replace the pinion seal. The third member case is made of aluminum and the ring gear is stamped 35:8 which makes the ratio 4.375. The seal that the parts store gave me is too big. I looked at CSK's web site and it lists different 620 pinion seal part numbers for '72-'73 and '74-'79. I had thought the aluminum third members were from the early trucks and 510 wagons. Can anyone shed some light on what this thing might be? The rear axle has been apart for sure because the axle seals were installed backwards. Steve, that is exactly what i always thought the aluminum carriers came from too. And the 72-73 truck should have had 4.375 gears too. Quote Link to comment
slodat Posted September 12, 2009 Author Report Share Posted September 12, 2009 Plot thickens a wee bit. The rear wheel cylinders are 5/8" which is correct for a '79. Me thinks someone switched out the third member somewhere along the line.. Thoughts? Quote Link to comment
yello620 Posted September 12, 2009 Report Share Posted September 12, 2009 Plot thickens a wee bit. The rear wheel cylinders are 5/8" which is correct for a '79. Me thinks someone switched out the third member somewhere along the line.. Thoughts? Measure the WMS to WMS to verify the axle width. 78/79 truck are about 2.25" wider than the 77 and earlier trucks. This would tell you if the housing is correct to the truck, and just third member was changed. However, i do not know the width's of the different years of trucks, just that they are different. But it can be found with enough searching, i have seen the numbers posted before. Quote Link to comment
slodat Posted September 12, 2009 Author Report Share Posted September 12, 2009 Is the aluminum carrier desirable for any reason? Quote Link to comment
yello620 Posted September 12, 2009 Report Share Posted September 12, 2009 Not necessarily. I have one in my truck with 3.89 gears. The aluminum was no advantage though. I like seeing it look clean under my truck though.:D Mine came from a 510 wagon. Quote Link to comment
slodat Posted September 12, 2009 Author Report Share Posted September 12, 2009 Some info for anyone headed down this path in the future: Early (to '73) H190 pinion seal - Nissan#38189-A6100 (the SKF seal I got was not near the quality of the original seal) All inner axle seal - Beck Arnley#0521575 All outer axle seal - Beck Arnley#0521542 or National#1974 The pinion seal does not have a crush washer under it. The pinion yoke just bolts to the pinion. I'll post up results once I get a new pinion seal and get it all back together. Quote Link to comment
datzenmike Posted September 13, 2009 Report Share Posted September 13, 2009 Not necessarily. I have one in my truck with 3.89 gears. The aluminum was no advantage though. I like seeing it look clean under my truck though.:D Mine came from a 510 wagon. Goons and Roadsters also had the aluminum case but different ratios and side gears from the 521/620. Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.