rear differential "replacing pinion seal" info/inquiry

Here's some good repair guides for your Tercel :) Look here for help first!
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xirdneh
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My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

rear differential "replacing pinion seal" info/inquiry

Post by xirdneh » Sun Jul 22, 2018 12:55 pm

i watched the noted (below) video and thought it was excellent
it got me to thinking about how to re-tighten the nut after replacing the pinion seal on our Tercels

https://www.youtube.com/watch?v=dAqAqODmcj4

so i made a new pinion seal video
https://youtu.be/z_eGBPxU5Jk
Last edited by xirdneh on Sat Aug 11, 2018 4:32 pm, edited 1 time in total.
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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Petros
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Re: rear differential "replacing pinion seal" info/inquiry

Post by Petros » Mon Jul 23, 2018 12:22 am

that might work if the nut was well lubricated and came loose at the preload value after it has been in the car for 30+ years. Seems that would be a tall order.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
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splatterdog
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Re: rear differential "replacing pinion seal" info/inquiry

Post by splatterdog » Mon Jul 23, 2018 4:04 pm

Another method is to scribe a line accross the tip of the pinion shaft, nut, and driveshaft flange and put it back exactly the way it was. Red loctite on threads..

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xirdneh
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My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: rear differential "replacing pinion seal" info/inquiry

Post by xirdneh » Mon Jul 23, 2018 8:24 pm

clarification The preload is not the tightness of the nut measurement
Its the pressure on the bearings tested by rotating pinion shaft and measuring the torque it takes to rotate it.
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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xirdneh
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My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: rear differential "replacing pinion seal" info/inquiry

Post by xirdneh » Thu Jul 26, 2018 11:42 pm

Tercel 4WD Rear Differential Pinion Seal Removal and New Seal Installation
I studied the 1983 Factory Service Manual (FSM), Chiltons ’84-94 and Bentley manual for ‘83. This is what I gather.
1. The pinion shaft has two bearings.
2. The bearings are the angled roller style with race.
3. The bearings have a spacer between them that is adjustable.
4. The manuals show crush type bearing spacer as the adjuster .
6. The purpose of the adjuster is to get the correct pressure (aka Pre-load) on the bearings.
7. The manuals say to replace the bearing and the spacer. The bearing race can be pulled with a special puller and the bearing and bearing spacer removed.
8. The pressure on the new bearing can be set by tightening the 24mm nut on the forward end of the pinion shaft. I say “can be” because it’s really the spacer that determines this. With the crush type spacer it’s the crushing that determines it. With the crush type you can crush it too much. When that happens, you have to start over with a new crush type bearing spacer. That being said you do have some control with the tightening of the 24 mm nut.
9. The correct pressure is measured by using an inch/pound torque wrench (preferably one with a dial on it). This is done by putting a 24mm socket on the torque wrench and using the torque wrench on the pinion nut to rotate the pinion/ring gear assembly that is the complete assembled rear differential. How much torque does it take to rotate all of the the gears around? It should be between 5.2 and 9.6 inch pounds. If differential is still in the car the axles have to be pulled to do this test.
10. I have two 85-88 differentials (4.1 ratios) that have never had the pinion seal replaced. I tested them and one was 5 in/lbs and the other 2.5 in/lbs. So if I replace the seal they should be ok if I get them back to those numbers and probably ok if between 5.2 and 9.6 in/lbs. (Note: the manuals do not recommend doing it this way)
11. The 83 FSM and Chilton manual says that maximum torque on the 24mm nut is 174 ft/lbs (minimum 69 ft/lbs). The Bentley manual just states a maximum of 144 ft/lbs.
12. Your supposed to tighten the 24mm nut in 9 ft/lb increments, checking pre-load at each increment until you get between 5.2 and 9.6 ft/lbs of pre-load.
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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ARCHINSTL
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Re: rear differential "replacing pinion seal" info/inquiry

Post by ARCHINSTL » Thu Jul 26, 2018 11:59 pm

Another "sticky" for xirdneh!
Props, Bro!
Tom M.
T4WD augury?
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xirdneh
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My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: rear differential "replacing pinion seal" info/inquiry

Post by xirdneh » Fri Jul 27, 2018 1:51 pm

This is what I did.
I replaced the seal on a ’83 (3.73 ratio) differential. It already had the 24mm nut removed so I did not get a baseline pre-load measurement before doing anything. I hand tightened the nut as hard as I could and checked the pre-load at about 2.5 in/lbs. then I torque it to the minimum 69 ft/lbs and the pre-load check stayed the same. The original locking notch on the nut was now about 1/4” from the shaft locking slot. I tightened the nut another ten ft/lbs and checked the pre-load, still no change. I repeated this until the notch on the nut lined up with the locking slot. It ended up around 115 ft/lbs. I am positive the nut is back to its original tightness. I believe taking the nut around 360 degrees more (so notch lines up with slot again) would put the torque way over the 174 ft/lb maximum. Pre-load ended up about 3 in/lbs.

When I do the next one I plan to: 1. Measure pre-load first for baseline. 2. Carefully count the rotations of the 24mm nut as I remove it. 3. After replacing seal carefully count the nut rotations getting it back to the same place but also checking pre-load every 10 ft/lbs as I go. 4. Hopefully pre-load will match the baseline when the nut reaches required rotations and the original nut notch lines up with locking slot.
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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xirdneh
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Posts: 1836
Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: rear differential "replacing pinion seal" info/inquiry

Post by xirdneh » Sat Aug 11, 2018 4:33 pm

i edited the first post
adding this new video for replacing pinion seal
https://youtu.be/z_eGBPxU5Jk
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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