Front Diffierential Seals leaking

I have a '97 Blazer 4dr.
I have noticed that I have gear lube leaking under the vehicle. A mechanic told me that it was my front differential seals. I was quoted $500 to replace them. At this point that is a lot of money to throw down. Is it ok to just keep filling lube periodically and limping along with the problem. I pretty much never put it in 4wd, and I understand that might be the root cause of the leak, since the seals dry out if not used.
Is the front differential engaged/spinning when not in 4wd? If all the fluid were to leak out and I never use 4wd would the front differential lock up and make the vehicle undriveable?
The vehicle has a lot of miles on it, and hesitate to throw a lot of $$ at it.

keep it full and you will be ok for a while.
if it does not have lock-outs the diff. will spin.
If it spins and runs out of oil, your screwed.
try a heaver lube.
When I was a kid I would put a hand full or two of fine saw dust right in the rear end with the oil.
stoped every leak, every time.

keep it full and you will be ok for a while.
if it does not have lock-outs the diff. will spin.
If it spins and runs out of oil, your screwed.
try a heaver lube.
When I was a kid I would put a hand full or two of fine saw dust right in the rear end with the oil.
stoped every leak, every time.
By lockouts, if you mean the ones in the center of the front wheels, then I do not have those. The saw dust trick scares me a little though:smile: I will definitly keep it full then. Thanks

Yea, I would not recomend for anyone to ever do that, just telling you what we used to do back when. Still consider steping up to a heavyer fluid.

Is it leaking from the front pinion seal? If it is, the seal is about $10 but it will take an hour or so to replace it.

Is it leaking from the front pinion seal? If it is, the seal is about $10 but it will take an hour or so to replace it.
I do not know what a pinion seal is or its location. I will look in a repair manual to educate myself and try to see for myself where the leak is actually coming from. At this point I am just taking the mechanics word for it, which is not always a good situation for an ill informed customer.
A little more history on the vehicle, this is not the first time I have had the front diffierential seals replaced. They were done about 4-5 years ago. I hate to pay for them again. But if it is something like a $10 part and an hour of labor, that does not sound too bad to me. I will look into it.
Thanks,
N8

Seals are cheaper than the rear end.
May just be one seal or all of them.
Have a look and see what one or ones are leaking.
Post back which ones and someone can help you with the replacement.
MT

Seals are cheaper than the rear end.
May just be one seal or all of them.
Have a look and see what one or ones are leaking.
Post back which ones and someone can help you with the replacement.
MT
It for sure looks like the drivers side seal on the front differential is leaking. The passenger side is more difficult to tell since it looks like the drive shaft rides inside an outer tube that connects to the passenger side front differential. Closer to the CV joint on the passenger side it is wet from what appears to be gear lube by the feel and smell of it.
On the aft side of the front differential there does not appear to be any leaking where the shaft comes in from the transfer case.

Yea, I would not recomend for anyone to ever do that, just telling you what we used to do back when. Still consider steping up to a heavyer fluid.
The owners manual calls for 80w-90 in the front and rear differential. What weight of fluid are you recommending?

It for sure looks like the drivers side seal on the front differential is leaking. The passenger side is more difficult to tell since it looks like the drive shaft rides inside an outer tube that connects to the passenger side front differential. Closer to the CV joint on the passenger side it is wet from what appears to be gear lube by the feel and smell of it.
On the aft side of the front differential there does not appear to be any leaking where the shaft comes in from the transfer case.

You should be able to remove the axel shaft and pull out the stub in rear end and put in a new seal.
You can do it DIY a lot cheaper than 500 the shop wanted.
A seal and a 1-2 hrs labor should get it.
Good Luck
MT

You should be able to remove the axel shaft and pull out the stub in rear end and put in a new seal.
You can do it DIY a lot cheaper than 500 the shop wanted.
A seal and a 1-2 hrs labor should get it.
Good Luck
MT
Have you seen any good How To's on the front differential seals? In the How TO section is saw a Thread on Ball Joint Replacement that got me part way there.

A good factory service manual.
Check E bay.
All data online sub.
http://www.alldata.com/products/diy/index.html
Public Libary has some car repair info.
AZ web site may have some info.

But it is remove the axel shatf.
Some you will need to take off or cut off and replace the sway bar link to get axel shaft out.
The stub in rear end where the axel bolts on will pops out just like a front wheel axel shaft.
It has a lock in ring on the end of it to hold it in.
Quick jerk or tap while turning it usually gets it out.
After stub is out you can see the seal.
A seal puller bar with a hook on the end will get seal out.
Drive seal in with a seal installer.
Az may have a rental or loaner seal installer or seal remover.
I have used a 3/4 in socket that fits the outer enge of seal works good for a driver.
Good Luck
MT

MT-2500
Thanks for all the helpful adivce. I am actually starting to gain some confidence to give this a try. I live in WI and it has been far too cold to do this kind of job. I will have to limp along for a couple of months and maintain the front differential lube level. I will start looking for a good manual, probably start with the library like you suggested. Thanks again!

You are welcome and good luck.
Also brouse the AZ web site they sell all data and have some of the info online in there site.
MT

You are welcome and good luck.
Also brouse the AZ web site they sell all data and have some of the info online in there site.
MT
Yes, I found a good diagram and procedure on the front differential in the free repair guide from AZ that is posted on the main page of this Blazer forum.

Sounds good.
And they sometimes have the special tools to rent or loan.
Let us know how it goes.
Good luck.
MT