Tercel differential rebuild questions

[Esaus]

An update on the rear differential.
I removed the rear axles and noticed when rotating the hub that it was notchy and noisy. After taking the rear axles out i felt that there was some noise and play in the wheel bearing in the axial direction. I ordered new wheel bearings for the rear with all the gaskets. They also looked rusty on the outside and that grease had leaked out from them alittle.

Today i removed the differential itself. It looks ok with no noticable wear that I can see. It rotates fine and no wierd noises from any bearings or gears. I can see marks from old paint on the pinion gear so someone has been in the diff at some point.

I tried pushing down on the pinion bearing while rotating and i neither felt or heard any noises or rough patches on the bearings. Im assuming the pinion bearings themselves are ok. I dont have a bearing puller to remove the bearings from the front so I didnt want to start tearing it apart just to look.

I have purchased a dial indicator to check backlash etc.
The ringgear runout was well within 0.07mm.
RIng gear backlash was 0.2mm so its outside of the 0.1-0.15 mm. I will try to adjust the adjusting nuts to fix this.
I also checked the tooth contact with paint and it was somewhat off center. I will recheck this after i adjust the backlash. I dont have any shims to fix any more than the backlash so it will have to do with whatever the results are.

When i started to remove the axle nut I notived it started loosening at 100Nm. According to the workshop manual for an 85 tercel that I have it should be set at 140 Nm. It was 9 revolutions out from the axle.
I replaced the dust seal and reassembled the axle nut to 100 Nm again.

Should i tighten it to 140 Nm to be sure? I don't have a torque guage to measure the preload to that sensitivity of 0.4-0.7 Nm as the manual suggests.

whats your thoughts or experience?

[xirdneh]

Maybe it’s the rear axel bearing
It’s easy enough to pull axles
Cup bearing in hand and spin shaft
Should be silent and smooth

It’s not worth rebuilding rear diff
Just find a replacement

[Esaus]

Maybe it’s the rear axel bearing
It’s easy enough to pull axles
Cup bearing in hand and spin shaft
Should be silent and smooth

It’s not worth rebuilding rear diff
Just find a replacement

Ive already checked the bearing. My last post had the details. I think the side gears might be worn. I will check backlash on them today.

[Esaus]

Another update.
Checked the sidegear backlash which was 0.2mm. The spec says it should be between 0.02-0.15mm. I would need to shim them up abit but i dont have any shims so I will leave them at that.

I adjusted the ring gear backlash from 0.2 to 0.13 by adjusting the adjusting nuts one notch. Loosened on one side and tightened on the other side. I toruqed the bearing cap nuts to 59Nm according to the manual.

The wear pattern was slightly improved but not perfect.

had to make a gasket for the diff from gasket paper. Ill assemble it all next week when the new bearings arrive.

[Esaus]

Conclusion:
Ive test driven the car. In 4WD the car runs smooth without any noise at all. Its noticeably nicer to drive. I guess the new wheel bearings, adjustment and thicker oil did its work.

Still when i lay off the gas and the rear coasts i hear the noise.
Its quieter and wont always come. I suspect its the play in the side gears that cause this as they rotate freely without load and the axle just rotates.

I cant do anything about it. The diff wasnt that worn or had much metal in it so i wont be too bothered with it. I guess i will keep a look out for a shim kit or replacement side gears if any come up on ebay or such.

Hope some finds this information useful in their fault finding or questions about the diff.

[Paul]

Good to hear you're back on the road. Thanks for following up with the details. A conservative adjustment of ring gear backlash sounds like a step in the right direction. Maybe the noise will reduce some after the gear teeth wear in to the corrected contact pattern.
The other day I jumped into my Jetta after driving the wagon for a few weeks. I was shocked at how smooth and quiet it drove. I guess there's a trade-off to driving a T4WD!

[dlb]

The other day I jumped into my Jetta after driving the wagon for a few weeks. I was shocked at how smooth and quiet it drove. I guess there's a trade-off to driving a T4WD!

I had a similar incident recently. I had been driving the Tercel for a month or so, then needed to drive our 1991 Corolla wagon and was amazed at how much quieter, faster, and more powerful it was. But that said, it still didn't have the magic that the Tercel does. Sold the Corolla not long after that.

[Esaus]

I have a corolla wagon 1988 with the 4wd. It is indeed more powerful. Mine has issues and im restoring it currently. The mechanical issues are soon fixed. just needs to be prettier

[Toyotise]

Highly recommended this for ameliorating gear noise in worn gear sets. No downside if it’s just going into the rear diff.
https://www.liqui-moly.com/en/us/mos2-a ... tion-title

[Esaus]

Highly recommended this for ameliorating gear noise in worn gear sets. No downside if it’s just going into the rear diff.
https://www.liqui-moly.com/en/us/mos2-a ... tion-title

Ive thought about the exact same addative. I might get it. The diff has ran well since the rebuild. I just did a 4000km trip over christmas without issues.