Front Differential Bushing Replacement - the Easy way! (2 Viewers)

[WeCruise]

Well my front bushing was shot, and I managed to swap it over the weekend. But I could really use some help with the rear bushing/mount in the photo below. To start it off, when I went to put the bolts back in, I managed to strip the left bolt hole. I tried to clean out the thread with a tap because that's about all I could find but the threads are shot. I called about 10 shops and no one can actually give me an estimate on rethreading the bolt hole. The estimated number is $500-$800 which seems crazy to me. Options I guess would be retapping to a larger size bolt hole or using a helicoil? I've never done either of these. The bolt is a m14 x1.5 which is pretty big.

Also any tips for removing the bolt for the bushing? I've used an impact wrench, breaker bar, blow torch. Can't get any leverage on the top nut. I have no idea why it's not coming out but it's been tougher than my rear shocks . Could really use some input!

 

[ClassyJalopy]

The nut on the top of the bushing bolt is designed to not move! You should try to turn the bolt instead. It can be pretty tight (the factory torque is 137 lb ft). On my first truck I had to put a long cheater bar on it to get it moving. Even then I had to curl up in the fetal position and push with my legs! Once you break it loose, put a 19mm box wrench on the top and just turn the bolt out.

Well my front bushing was shot, and I managed to swap it over the weekend. But I could really use some help with the rear bushing/mount in the photo below. To start it off, when I went to put the bolts back in, I managed to strip the left bolt hole. I tried to clean out the thread with a tap because that's about all I could find but the threads are shot. I called about 10 shops and no one can actually give me an estimate on rethreading the bolt hole. The estimated number is $500-$800 which seems crazy to me. Options I guess would be retapping to a larger size bolt hole or using a helicoil? I've never done either of these. The bolt is a m14 x1.5 which is pretty big.

Also any tips for removing the bolt for the bushing? I've used an impact wrench, breaker bar, blow torch. Can't get any leverage on the top nut. I have no idea why it's not coming out but it's been tougher than my rear shocks . Could really use some input!

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[WeCruise]

The nut on the top of the bushing bolt is designed to not move! You should try to turn the bolt instead. It can be pretty tight (the factory torque is 137 lb ft). On my first truck I had to put a long cheater bar on it to get it moving. Even then I had to curl up in the fetal position and push with my legs! Once you break it loose, put a 19mm box wrench on the top and just turn the bolt out.

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Good to know about the top nut. I'll give it a shot. After stripping that other bolt hole, I'm worried about snapping the bolt.

 

[ClassyJalopy]

Good to know about the top nut. I'll give it a shot. After stripping that other bolt hole, I'm worried about snapping the bolt.

you can try to snap that bolt. That sucker is industrial size! And if you do it won't be stuck in your frame, you can easily replace it.

 

[WeCruise]

you can try to snap that bolt. That sucker is industrial size! And if you do it won't be stuck in your frame, you can easily replace it.

I was able to get it! Did exactly what you did, got a long cheater bar and pushed with my feet and it broke loose! Thanks for the tip.

 

[Slickspawn]

I did my front bushing and replaced the rear and side arms of my front diff on Friday afternoon last week.

I followed @flintknapper method and used a 1-1/2” hole saw to core out the rubber. Then I used a wood chisel since mine are flat on one side to bend the lip down with my handheld sledge tapping. Once I got a nice and clean gap between the front diff cover aluminum mount housing and the bushing lip I switched to cold chisel and 5lb sledge with a short handle. I worked it for a good 5 minutes and then it was ready to come out and further chiseling just wedged it back and forth. I grabbed the bushing with some channel locks and it pulled right out.

No need for air tools. While I have them I didn’t like all the mis-hits shown in this thread from the air hammer going awry.

I did freeze my replacement bushing overnight and used my ball joint press and installer cup BJP1-14A which is a 2-11/16” ID adapter and some M1 grease and it slid right in.

Nice incremental improvement in clunk reduction!

 

[TheRealPoser]

Slight tangent, but I installed a diff drop and my next step is to replace the front diff bushing. I replaced the support cross member, then with the diff supported I removed the rear support bolt, added the drop kit spacer, then put the new bolt and nut in place. I then removed the front support bolt, diff still supported with a jack. I was going to put the spacer in and put the bolt back just to hold everything in place until I can get back out to hammer out the bushing. However, the diff shifted a little and the front support is no longer aligned with the blind nut above. It's not a lot, maybe 1/4-1/2 inch both to the rear and driver's side, but it's enough that there is no way I can get the bolt back. I've been battling the thing for an hour now trying to "persuade" it back, but I can't get the thing to budge. Even my choicest words don't seem to help this time! Any tips? All the other bolts are not even finger tight, so it's not that I've tightened it down misaligned. I'm not about to try and force in that bolt at a wonky angle and strip out the blind nut, but I'm stuck.

 

[ClassyJalopy]

Slight tangent, but I installed a diff drop and my next step is to replace the front diff bushing. I replaced the support cross member, then with the diff supported I removed the rear support bolt, added the drop kit spacer, then put the new bolt and nut in place. I then removed the front support bolt, diff still supported with a jack. I was going to put the spacer in and put the bolt back just to hold everything in place until I can get back out to hammer out the bushing. However, the diff shifted a little and the front support is no longer aligned with the blind nut above. It's not a lot, maybe 1/4-1/2 inch both to the rear and driver's side, but it's enough that there is no way I can get the bolt back. I've been battling the thing for an hour now trying to "persuade" it back, but I can't get the thing to budge. Even my choicest words don't seem to help this time! Any tips? All the other bolts are not even finger tight, so it's not that I've tightened it down misaligned. I'm not about to try and force in that bolt at a wonky angle and strip out the blind nut, but I'm stuck.

Try using a pry bar on the diff body to align the holes better or may be even jack it up a little to see of you can better alignment

 

[TheRealPoser]

Managed to get it! I took out the large bolt on the driver's side front diff support mount, then with my left foot on the cross member and right hand prying on the jack handle wedged between the axle tube and the bolt that holts the tube to the diff I was able to pull hard enough with my right hand while threading the bolt with my left. Then I had to get under the axle tube and basically do a one handed bench press on the tube to get the bolt back in the other mount. That was my car yoga for the day for sure

 

[TheRealPoser]

Btw, used a flat head screwdriver and a chisel to slowly work the old bushing out. It was much easier than expected. Maybe 5-10 min tops and I wasn't trying to set any speed records. Not a job to be afraid of.

 

[yj668]

Does the diff just drop low enough for a ball joint C clamp to fit on with just the front bushing's bolt out or will loosening the side and rear support arm assy bolts be necessary to get the droop?

 

[flintknapper]

Does the diff just drop low enough for a ball joint C clamp to fit on with just the front bushing's bolt out or will loosening the side and rear support arm assy bolts be necessary to get the droop?

Diff cover dropped enough on mine to get the clamp in place with removal of only the bushing bolt

 

[yj668]

The rear arm's really close to the factory AC drain location. The condensation drains on the #2 plastic skid plate and moisture stays on the skid and it's difficult to get that fully dried up. Stuff surrounding the area might start to rust as a result (diff rear arm bolts, sway bar, sway bar bushing mounts etc). It is possible to get frame rot in that area for rust belt trucks.

On my SoCal no rust on frame LX, the long bolt of the rear arm had a coat of corrosion and rust. Torque wrench measured 193 ft lbs when breaking the bolt with nature's best loctite. It snapped loudly 3 times before it starts to take less effort to unbolt that. Bought a new set of bolts for the front diff rear arm for R&R. Never know how deep the corrosion went into the bolts.

You're probably having a similar issue breaking rust and corrosion on the bolt. If the top bolt spins, use a combination wrench, box wrench or adjustable wrench to hold that. Use the longest breaker bar or wrench you can find.
Car yoga is necessary, find points you can hold on (tires or frame) to while you kick/step on the wrench.

Well my front bushing was shot, and I managed to swap it over the weekend. But I could really use some help with the rear bushing/mount in the photo below. To start it off, when I went to put the bolts back in, I managed to strip the left bolt hole. I tried to clean out the thread with a tap because that's about all I could find but the threads are shot. I called about 10 shops and no one can actually give me an estimate on rethreading the bolt hole. The estimated number is $500-$800 which seems crazy to me. Options I guess would be retapping to a larger size bolt hole or using a helicoil? I've never done either of these. The bolt is a m14 x1.5 which is pretty big.

Also any tips for removing the bolt for the bushing? I've used an impact wrench, breaker bar, blow torch. Can't get any leverage on the top nut. I have no idea why it's not coming out but it's been tougher than my rear shocks . Could really use some input!

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[yj668]

Diff cover dropped enough on mine to get the clamp in place with removal of only the bushing bolt

Thanks, that worked really well. Hole saw and 30 minutes of beating the bushing out with a cold chisel. Was afraid I may butcher the front mount with my tired arms on air tools.
Replaced the rear arm cushion while I was working on the front bushes.

New FDS + hub flanges, new front diff bushings + greased drive shaft eliminated clunk and thunk.

 

[TheRealPoser]

Managed to get it! I took out the large bolt on the driver's side front diff support mount, then with my left foot on the cross member and right hand prying on the jack handle wedged between the axle tube and the bolt that holts the tube to the diff I was able to pull hard enough with my right hand while threading the bolt with my left. Then I had to get under the axle tube and basically do a one handed bench press on the tube to get the bolt back in the other mount. That was my car yoga for the day for sure

In case it's useful to someone in the future, I found that removing the large bolt through the bushing on the driver's side front support bracket on the axle tube was necessary to get the front diff mount to line up with the blind nut in the cross member. If you look closely at the picture I posted above, I was missing the large metal washer that goes below the bushing. I was so focused on trying to get the bolt aligned that I forgot to include it, so I had to take the bolt out again. Sure enough, pry as I might, I could not get it to line up again. So the 2nd time I also pulled that other bolt, and that allowed the diff to shift just enough to align with the hole, still with a fair amount of prying. However, it was a lot easier to get that other bolt back in by simply pushing the axle tube straight up. If anyone finds this because you're having the same issue, I recommend doing the same thing. I'm not sure I could get it otherwise. There aren't actually many good places to pry on if you want the diff to move forward, as the oil pan is above the diff.

Oh, I'll also note that I had a devil of a time getting the front bushing to go in straight. I also used a ball joint press, but the new bushing is so tight it wants to flip to one side every time. I didn't see any mention of this here, but I saw one passing mention in the comments on YotaMDs youtube video that it's ok if it's not going in straight. After that I just started cranking down more pressure with it cocked sideways and it eventually popped into place straight on its own. Before that I was afraid to smash it in at an angle and damage something or have to hammer it back out and damage the new bushing. Your mileage may vary, but it worked for me anyway.

 

[Tbone81]

I am stuck trying to remove the two bolts that secure the differential mount to the axle. I know they are tight from the factory but I have cranked my 1/2” torque wrench all the way up since it has a long handle and cannot get them free. I used a 1/2” impact and still nothing. I have pushed as hard as I feel comfortable with a cheater bar and am beginning to be concerned that I may round off the head. Anyone have other suggestions. Every other bolt on this truck has been a breeze to remove with no rust. I am at loss for how to proceed.

 

[flintknapper]

I am stuck trying to remove the two bolts that secure the differential mount to the axle. I know they are tight from the factory but I have cranked my 1/2” torque wrench all the way up since it has a long handle and cannot get them free. I used a 1/2” impact and still nothing. I have pushed as hard as I feel comfortable with a cheater bar and am beginning to be concerned that I may round off the head. Anyone have other suggestions. Every other bolt on this truck has been a breeze to remove with no rust. I am at loss for how to proceed.

Use a 'well fitting' 6 point socket and a 3/4" breaker bar. They are tight.....no doubt about it.

 

[Tbone81]

Use a 'well fitting' 6 point socket and a 3/4" breaker bar. They are tight.....no doubt about it.

Will heat help at all?

 

[Slickspawn]

@Tbone81 you are using your torque wrench to loosen bolts?

 

[Tbone81]

@Tbone81 you are using your torque wrench to loosen bolts?

It was the longest thing I had to get max torque on it at the time. Then became curious as to what torque it would actually let loose. Cranked incrementally until maxed out torque setting at 250 ftlbs. No luck. Then I borrowed an impact and no luck again. I will go borrow 3/4 drive breaker bar tomorrow and try again. It just seems strange that impact rated at 400 ftlbs in reverse did not remove.