Motor Mounts

[Thawk97]

So, I know there are like a billion threads from ancient history on motor (& tranny) mounts. I've done a bunch of reading on the how to's and stories/examples of bad mounts once they've been removed etc. Also, read a fair amount regarding the Woodhouse poly mounts vs stock - some added initial vibration which fades a bit over miles etc.

My question is looking for some help assessing whether I should be replacing mine or not. I'm going to be pulling the headers in the next week or so which is what is prompting the question - as long as I have things torn apart and the space to work, if they should be replaced (or will in the near future), I might as well do it now. My hesitation is that I don't actually know whether it's entirely necessary and if I do replace them, I'm thinking I'll go with the Woodhouse mounts for longevity - so that's a ~$375 question (I am open to arguments on OEM vs Poly - 99% of everything else on my car is going back to factory).

To my car then:
I did a quick visual inspection of the motor mounts from the top and neither driver nor passenger is pancaked or has any really obvious distortion (though you can't see all the rubber). My car ('96 GTS) has 53k miles on it and I have no idea if they've been replaced before or not. On engine start, the motor does move a bit, but not really more than I expected - hard to gauge exactly how much movement. The shifter moves toward the passenger about 1/4" or so when I start rolling from a standstill under very light load, and under hard acceleration maybe another 1/4" or so. So in total it plays between 1/4" and 1/2" toward the passenger under varying levels of acceleration. I haven't done a hard launch with a quick shift to try and feel movement while attempting to grab 2nd. Again - nothing that seems extreme, but observable movement in the shifter. When the car idles for more than a minute or two it does sometimes get into a vibration rhythm where the whole car rocks a bit left/right. This is observable both inside and outside the car.

So - kind of feels like I could be convinced either way - that everything sounds normal and don't waste the money. Or that there's enough movements & vibration happening it'd be good to swap them. Just looking for peoples insight & opinions if they feel so inclined.

Thanks!

[RPM9000]

On my Gen.1 I was having shifting problems at full throttle. I thought it was due to bad motor mounts so I replaced them with Woodhouse motor and transmission mounts. It did not remedy my shifting problem. My old stock mounts looked good until I took them out and one of them was broken.

[VoodooRob]

On my 97 the original mounts looked good until I took them out and 1 was not good at all. My car has 10k miles. If you do the motor mounts make sure you install the factory heat shields correctly, also do the trans mount at the same time.

[Hiss Highness]

I thought the gen 2 motor mounts were the same as 1st gen dodge cummins mounts

[C.J]

With that age and that mileage, it would be prudent to replace the mounts. If you're not going to track it, OEM should be fine and will save you quite a bit of $$$.

[Sybil TF]

At 27,000 miles my motor mounts and tranny mount were shot.

[ViperTony]

Replace them. I replaced mine after 9,000 miles. I used Woodhouse Mounts. Regarding the other mounts, the OEM rubber ones will eventually deteriorate again. The poly mounts were smaller than OEM and caused fitment issues with my aftermarket headers. The fitment issue being that my turnouts were hitting the frame after installing the poly mounts. One could shim them up for clearance. The Woodhouse are the easiest and imo the most well-designed. Some have had issue with woodhouse mounts melting but I believe Woodhouse now have shields for their mounts which prevents. In the 6 years I've had Woodhouse mounts I've never had an issue with them. I think they're your best choice. I do have an extensive DIY I will upload this weekend. It's not a complicated process.

[JonB ~ PartsRack]

Caution: OE Motor Mounts are really "Isolators" of engine vibration. I agree that 10-15 year old mounts need to be replaced at $39 each OE. Note: Mopar even calls them ISOLATORS, not Motor Mounts.

If you put in hard race-car motor mounts (Like Woodies) vs OE rubber, you WILL induce some vibrations into the cockpit, the instrument panel, and the shifter. Some older cars may start to vibrate- buzz- and Gen 4 KNOCK SENSORS (esp 2008) can actually dial back TIMING ! {Im not making this up} Some 2008s can trigger Limp mode.

If you have shifting missed-gear issues, first swap the OE rubber for a $45 trans mount of hard-poly-nylon. It WILL improve the shifter feel in most cases. CHEEP!

[Thawk97]

So follow up question based on your comments Jonb - is there a mount which maintains OE feel but won't wear out as easily as the OE rubber? I don't know that I need the performance (in terms of stiffness) of a race-car mount, but I would like to put something in that won't wear out quickly (esp if the OE rubber would already be several years old - not sure when the stopped manufacturing on them and how long they sit on shelves- time breaks down rubber).

[ViperTony]

My rear view mirror vibrated to the point where it would drop down. But it felt great. After some miles the vibration subsides. The woodhouse mounts keeps my shifter still, no vibration, no moving around, nada. But if you want to be cheap and pampered go for the OEM mounts. I agree with Jon on trying the transmission mount too. I have poly bushing trans mount I believe. Female passengers seem to love the extra vibration. Just sayin'.

[XSnake]

If you swap to the poly mounts make sure you also get the new bigger heat shields. Factory ones do not cover the full mount and they will melt. Ask me how I know.

[99RT10]

Female passengers seem to love the extra vibration. Just sayin'.

LOL. I agree with Tony, just replace them. If you want a little Vibration absorbtion, put an OEM mount on the right side. It doesn't see the torque like the left side and the rubber will still absorb some vibration.

[J TNT]

Exactly what I did , poly left engine mount and trans mount , factory right mount , shifting is greatly improved.

[JonB ~ PartsRack]

I think your shifting feel would be improved with the $45 Poly Trans Mt ALONE. A Gen 1-2 add Billet Trans BRACE also acts like a mid-ship anti-sway bar. CHEAP SWAY BAR, Really! Esp nice and effective in Gen 1-2 RT10. $79

I think the $39 OE motor mount isolators wont degrade in warehouse conditions. No heat-oil-fumes-road-film, and No TORQUING them on a shelf ! I don't think they are Cummins mounts, but MAY be RamV10 Mounts.


I don't like vibrating radar detectors, mirrors, cup-holder coins, and NVH on gauge needles, etc. I spend extra to Road Force balance EVERYTHING to stop that jiggling/buzzing.

[ViperTony]

I don't like vibrating radar detectors, mirrors, cup-holder coins, and NVH on gauge needles, etc. I spend extra to Road Force balance EVERYTHING to stop that jiggling/buzzing.

Drama Queen. it's a Viper not a Prius.

[Matt M, Pa]

I changed the mounts to all factory stuff on my '96 RT last summer. Tremendous improvement in driveability.

Jon B...and I know its off topic...I'd like to know more about the trans brace. Link?

[Sybil TF]

I believe. Female passengers seem to love the extra vibration. Just sayin'.

Not that kind...

[LifeIsGood]

Change the mounts (including transmission)...also put in a billet transmission cross member from IPSCO...



My 2 cents and your money.

[ViperTony]

not that kind...

lol

[mjorgensen]

Caution: OE Motor Mounts are really "Isolators" of engine vibration. I agree that 10-15 year old mounts need to be replaced at $39 each OE. Note: Mopar even calls them ISOLATORS, not Motor Mounts.

If you put in hard race-car motor mounts (Like Woodies) vs OE rubber, you WILL induce some vibrations into the cockpit, the instrument panel, and the shifter. Some older cars may start to vibrate- buzz- and Gen 4 KNOCK SENSORS (esp 2008) can actually dial back TIMING ! {Im not making this up} Some 2008s can trigger Limp mode.

If you have shifting missed-gear issues, first swap the OE rubber for a $45 trans mount of hard-poly-nylon. It WILL improve the shifter feel in most cases. CHEEP!

The Woodhouse "isolators" aside from improving shifting "accuracy" by positively locating the shifter will improve throttle response, because the engine is not allowed to "wind up and back" when you get on and off throttle like stock good or blown mounts can. The wheel hop that Vipers can get is also drastically reduced because of the same issue. I would also not replace just the transmission mount with a stiff one if not changing the engine isolators, if the engine is rocking sloppily and the transmission mount can't what do you think takes all the "stress" in that situation?

As for the timing and limp mode issues, out of the 500 plus sets I have sold there have been 2 known reported cases of throttle body electronics issues in Gen4 cars and these were on track only racecars. Any car can have over sensitive knock sensors, we have seen this with totally stock cars, changing sensors will likely take care of it if there were any problems. My personal 08' made 615hp at the tire using the mounts for 18K miles, dozens of track weekends, well over 200 autocross runs/Pro Solo launches and 3 high speed 9-13 hour road trips too Viper events. The only problem my car ever had was a grounded out O2 sensor on the passenger header.

Bottom line is that any part you can put on a car can cause a problem, but the Woodhouse mounts have an exceptional record of very happy customers, if they didn't I would not be selling them FWIW.

[Thawk97]

Thanks for your input everyone.

Talked with JonB this morning and he got me squared away - thank you sir!

Mark - if I ever end up hitting the track regularly, you might be hearing from me. Thanks for the info.

[Thawk97]

So I replaced the mounts and I'm getting more engine movement than before. My original mounts weren't in great shape, but I've seen worse on here. Driver's side had a small crack which didn't go all the way through.

I also replaced the exhaust with the factory stuff and my theory on the increased motor movement since I put in new mounts is that the aftermarket headers/exhaust which were in there had no flex pipe, so they were helping hold the motor still. The factory stuff had the flex pipe connected to the manifolds which might allow for more movement? Is that nutso? When I put the new mounts in I tightened everything down quite hard and made sure to knock on the mounts with a 2x4 and hammer to make sure they were seated all the way down.

Any other ideas - or is the exhaust swap likely the cause of more movement? Had I known there'd be more, I think I might have opted for the Woodhouse mounts instead - I really don't like the amount of shifter movement...