Posted: 10/17/2012 6:39:29 PM EDT
|
I have a tenant that dropped her 04 TB at a local garage for a tire repair....upon picking up the TB she drove it about 10 miles and a grinding, lurching condition developed to the point that the vehicle became inoperable.
The local garage was called and she was towed back there. She was told that a "plug" or "cap" had come off the front differential and she had lost all lubricant. Garage has advised that the diff is un repairable. She is now driving and rental and called me out of desperation feeling that she has been set upon be this garage. I know very little about front diffs, but agreed to stop by the garage in the morning and get some answers. 1. What should I look for to determine root cause of described anomaly? 2. Is it possible to just loose lubricant from a front diff. 3. would driving the truck 10 miles with no lube destroy the diff. 4. could new fluid be added and make the truck driveable? 5. could the front diff be disabled to essentially make it a 2 wheel drive? thanks to all my arfcom brothers for your help and opinion! Chuck |
I'm not a mechanic but I do drive a 4WD truck (off-road!). 
1. What should I look for to determine root cause of described anomaly? Poor maintenance? Blown seals? There might be leak stains or a missing filler plug. 2. Is it possible to just loose lubricant from a front diff. Yes - they're separate sealed systems from the transmission, engine, transfer case, and rear differential. 3. would driving the truck 10 miles with no lube destroy the diff. Not likely. But if it had a locking front diff and she locked it and made lots of turns on pavement ... really bad ju-ju. 4. could new fluid be added and make the truck driveable? It's worth a shot but not likely. The stuff isn't cheap by the bottle but it's a whole lot cheaper than an new diff! 5. could the front diff be disabled to essentially make it a 2 wheel drive? Yes, separate the shaft from the transfer case - on my truck it's done with U-joints. This is a field modification that rarely has to be done on the trail when someone "Glocks" a diff. |
|
Quoted:
04 TB???  Trail Blazer? And Diff plugs seldom [if ever] come out on their own without help. It is possible some quickie oil change place pulled it to check the gear oil level and forgot to replace it and driving on a low tire for awhile caused it to exacerbate the issue. |
|
Quoted:
Quoted:
I believe there is about 96K miles on the TB Yep...04 TB...only about a zillion out there She is worried that maybe the shop pulled the plug to gain a repair fee.... yet to be determined. WTF IS A TB???? Hey OP what vehicle is this: 01 NF Easy there big guy.... |
|
Quoted:
Quoted:
I believe there is about 96K miles on the TB Yep...04 TB...only about a zillion out there She is worried that maybe the shop pulled the plug to gain a repair fee.... yet to be determined. WTF IS A TB???? Hey OP what vehicle is this: 01 NF Nissan Frontier. 
|
|
Quoted:
Quoted:
Quoted:
I believe there is about 96K miles on the TB Yep...04 TB...only about a zillion out there She is worried that maybe the shop pulled the plug to gain a repair fee.... yet to be determined. WTF IS A TB???? Hey OP what vehicle is this: 01 NF Nissan Frontier.
I didn't ask you!!!1!11!! 
|
|
Diff plugs dont just "fall out". Then again, it would be a huge pain in the ass to get to it when doing a tire change.
Were they doing any other work to the vehicle? Maybe they took it out doing a "Check up" and forgot to put it back in. Diffs do not last long with out oil in them. Either way, i would be claiming the shop did it and wouldnt leave until they fixed it. Easy Solution: Go to the junk yard. TB's are a dime a dozen, just pull one and replace it. Also, use a little internet sleuthing and find a similar vehicle that shares the same front diff and swap that in from a junk yard to save yourself some coin. Wrong Solution: Pulling the Driveshaft. Do not do this. It will not fix or even offer you a bainaid aid to your solution. The CV shafts press into your unit bearings, which are directly linked to the rotation of your tires. Which means it moves the gears inside your diff at all times. period. |
|
TB front diffs are grenading at a rapid rate...diff is integral to the oil pan on the engine, so no cover to remove. It only holds about a pint and a half of oil, so a small leak results in rapid damage. Often I see a seal leak as the source of all the trouble
Job to remove and replace is about 10 hours, so not an easy access to look inside...the center axle actually passes through a tunnel in the engine oil pan and the case is trapped in the frame until the pan is removed. I have done 3 in the last 6 months |
|
Quoted:
Quoted:
Should be a plug to drain and fill. I agree whoever was working on it forgot to tighten it either on purpose or negligently.  I tend to agree also....why is it that women seem to get hit with this crap proportionally more than guys..... arrrrggggg Take pics of where she parks the TB, , to show proof that there were no leaks, or very little, BEFORE she took it to the shop and now she probably needs a new diff. if they don't make it right go to the local news station.
|
|
Without pics of .... inside differential, we cant be sure. It is certainly worth pouring a few pints of gear lube in, to see if the thing returns to drive-able condition.
Probably the last geek worked on it left the fill plug out. ten miles probably didnt destroy it. She needs a new mechanic. |
|
Quoted:
Quoted:
Should be a plug to drain and fill. I agree whoever was working on it forgot to tighten it either on purpose or negligently. I tend to agree also....why is it that women seem to get hit with this crap proportionally more than guys..... arrrrggggg Differential plugs are in my experience (F-150 and Merc Mountaineer) on TOP end of the differential. It is doubtful that even if the plug was left out all the fluid would drain out in 10 miles. I bet she just never had it checked. |
|
Quoted:
Quoted:
Should be a plug to drain and fill. I agree whoever was working on it forgot to tighten it either on purpose or negligently. I tend to agree also....why is it that women seem to get hit with this crap proportionally more than guys..... arrrrggggg suspicious timing |
|
Assuming she had no problems previous to the tire repair I highly doubt on a 4wheel drive - not all wheel drive - a disengaged front diff would detonate in only 10 miles with no fluid. Under normal driving conditions.
It's a stretch however they could have broken something in the diff if trying to take off the lug nuts and the wheel was trying to turn at the same time. Was it s front tire repair? They also could be full of shit and its something with the brakes or back plate causing the noise. They should show you the fluid without hesitation to see if it sparkles. Try to see if you can pinpoint where the noise is originating. If you are really not trusting them get the "TB" to another garage or to someone you can trust. She has had no other recent repairs? that could be related ? Any leaks in the driveway or parking spot at work ? Edit: some of you guys are quick man ........ last post I saw before started typing was about this shit happening more to women .... |
|
Quoted:
Repair was on the left rear tire.... last oil change was at a Jiffy Lube @ 2 weeks ago. Not sure if pulling diff plugs is SOP for a routine oil change there. Bingo! Plug is on the front right side of the Diff housing. Jiffy Boobs removed it and forgot to replace it. 2 weeks would just about do it............... |
|
1. First determine if the front diff has a drain plug or if it is one that you have to pull the cover off to drain the gear oil. If it has a bolt on cover with a rubber stopper type fill plug, i call major BS!!! I just don't see all of the oil coming out of the fill hole... If it has a drain plug, ask to inspect the threads, do they appear to be stripped? The shop I worked at always applied teflon tape to the drain plugs after a service to avoid leaking, is there any tape on the threads...? Ask your friend how many times the diff has been serviced (probably just one around 60k or so).
2. Yes it is possible to lose the gear oil from just the front diff. It is a completely seperate sealed unit from any other systems. 3. Hard to say without inspecting the gears prior to the breakage... What exactly failed, spider gears, ring gear, pinion gear..? If the gears were worn prior to losing the gear oil... its possible. 4. Probably not. If the damage was bad enough to make the vehicle inoperable, there was probably some sort of catastrophic failure, ie one of the gears broke... 5. Yes, you'll most likely have to pull both front CV axles and the front driveshaft though. However, if it is some sort of all-time 4wd or AWD this will throw all kinds of diagnostic trouble codes... There are a shit load of sensors on awd and full time 4wd cars... Do a little research about how a differential works prior to showing up. Learn how the spider gears, pinion gear, and ring gear work so that you'll know what you're looking at, |
|
Quoted:
Should be a plug to drain and fill. I agree whoever was working on it forgot to tighten it either on purpose or negligently. There's a fill plug, but no drain plug on most differential covers. You pull the cover to drain the diff, replace it, and fill it up to the fill hole. If the vent plug came off it could take weeks or months to drain the diff. But, since she said it was making noise, and she kept driving until she couldn't drive it anymore, the diff is most likely toast. If the fill plug was taken off, it would lose the fluid a lot, lot quicker. |
|
Can you take any pics of the carnage ?
If it is what I think it is, somebody is going to be making a trip to a junkyard and pulling a complete front differential. When these things grenade to the point of not being driveable, the case will be wiped out also. OBTW, pics of the female tenant please. |