Broken motor mounts

[bigd7315]

I have a 92 gmc sonoma 4.3 5 speed and I keep breaking motor mounts on the drivers side I have replaced it 3 times since 3/05 and that is rediculous I think I don't kick the truck around much and only tow a small 4x8 trailer that weighs 220lbs empty to haul a atv that weighs 600lbs I want to know how many others have this problem if any and did you solve it and how email me with answers at [email protected] thanks

[OverBoardProject]

I'll just post my reply, so everyone knows the answer.
It should get forwarded to you.

Poly urithane (sorry that I'm a bad speller) motor mounts are way stronger than stock. And should last way longer.

But they really shouldn't be braking like that.
I haul 3/4 cord of firewood behind my Blazer without any problems.

Do you have oil leaking onto it?

[herkyhawki]

Are you 100% sure the passenger motor mount And the transmission mount are good. If you have had that much trouble, I'd suggest changing all 3 at once.

[bigd7315]

I just checked the other mounts and the tranny mount is good and passenger side is good i have a rachet strap on the drivers side now to help since the poly mounts are not available no oil leaks so i am back to square 1 any other answers please

[sector95]

Three broken motor mounts in 5 months..... what have you been doing with the vehicle since the beginning of this year that you weren't doing before? When you do "kick the truck around" what are you doing? Pulling a hole shot or a burn out by dumping the clutch is an excellent way to snap a motor mount... or 2 or 3. Hauling way more load (firewood, a Bobcat, etc) than the truck is capable of is another way to bust mounts. "Brisk" driving while towing (starts and engine braking downshifts) can also put a lot of additional strain on mounts. IMHO, polyurethane mounts are not the solution on a stock truck. The engine needs to be able to move and have load shocks absorbed by the flexibility of the mounts. Also, normal idle vibrations from the inherently "shakey" 90 deg 4.3L V-6 need to be dampened....even with an engine with a counterbalancer... otherwise all shocks and vibration are transfered directly to the chassis.

mike

[bigd7315]

When I say kicking the truck around I mean that I might pass a car or speed shift once in a while and catch 2nd but thats rare mainly just normal driving and I said that the heavy thing I haul with the truck is a 05 suzuki eiger atv that weighs a little less than 600lbs on a 4x8 trailer that i purchased from pep boys for 299.99 that weighs about 200# so has anyone else having this problem i also have a hard time taking off in first gear because of the mounts giving and causing the truck to jump around alot i am going to see if the 3.42 gear is to steep for the truck I am also running a 255/60/15 on the back of the truck and most of the driving on the truck is hwy and around the apts I work at

[bigd7315]

I purchased the truck in march of this year and it had a broken mount when I bought it but it did not worry me having 174k now it has 182k and 2 new mounts and a broken 1 now that I will be changing tommorrow along with the other motor mount so they will be both new I have a rachet strap holding the motor down now

[sector95]

Originally Posted by bigd7315

When I say kicking the truck around I mean that I might pass a car or speed shift once in a while and catch 2nd but thats rare mainly just normal driving and I said that the heavy thing I haul with the truck is a 05 suzuki eiger atv that weighs a little less than 600lbs on a 4x8 trailer that i purchased from pep boys for 299.99 that weighs about 200# so has anyone else having this problem i also have a hard time taking off in first gear because of the mounts giving and causing the truck to jump around alot i am going to see if the 3.42 gear is to steep for the truck I am also running a 255/60/15 on the back of the truck and most of the driving on the truck is hwy and around the apts I work at

So here's what you've got:

5-speed manual tranny

rear anxle ratio of 3.42.... is this stock or did the previous owner slip in some "performance" gearing?

you've got extremely low profile tires for a truck (60 series).... the stock sized tire is a 195/75-14, factory optional tire is a 215/65-15


The 4.3L is a torquey engine and you've got a manual tranny. I believe you've got a combination of low final gearing and a low profile tire (which has the effect of lowering further your final drive ratio). The towing adds just the right amount of resistance and with your very low final drive you're setting yourself up for disaster (3 busted motor mounts in 5 months). Me, myself and I would swap out the tires for a stock set.... I think you'll find your motor mount problem will go away.....


mike

[bigd7315]

the stock tire size is a 27 inch tire a 255/60/15 is a 27 inch tire just wider where stock is a 7 in wide I am running 9 1/2 inch wide the 3.42 I put in 2 months ago along with a new clutch

[bigd7315]

just got it fixed today since poly mounts are not available I made my own I took a stock set and drilled a hole through the center and put a grade 8 bolt through them to keep them from breaking now I will find the next weakest link in my drive train

[bigd7315]

just for every one to know that is the best fix to do no other mount will work without changing the frame mounts on a 4.3 and when you buy replacement mounts do not use the pioneer brand from advance they are really cheap and have recalls on the

[herkyhawki]

Originally Posted by bigd7315

just got it fixed today since poly mounts are not available I made my own I took a stock set and drilled a hole through the center and put a grade 8 bolt through them to keep them from breaking now I will find the next weakest link in my drive train

Be prepared in case you find "next weakest link in my drive train" is a cracked engine block.

[bigd7315]

if so it will be a good excuse to put the 350 tbi in it that is waiting

[OverBoardProject]

That's the spirit bigd7315!

The only problem is that you'll brake more motor mounts with the 350 installed

[bigd7315]

but I will make a good smoke show while breaking it lol