Possible problems caused by a MML?

TJim

TJim

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Hey everyone!

After lifting my TJ (3" front, 2.5" rear) I have some vibes.

Tomorrow, I am going to lower my TC's skid plate, with some washers and longer bolts, just to be sure that this is the problem.

I read a lot of threads that suggest MML as a mod to eliminate vibes and get rid of TC drop.

My question is if there are any problems caused by the MML. Even in a small rate. Any problems by changing the angles of the engine, transmission, transfer case?
 
A MML reduces the angles at the rear driveshaft similar to how a tcase drop does. For that size suspension lift a MML might be enough to eliminate the vibrations.

Just make sure to not use any MML product that uses polyurethane bushings as they will pass engine vibrations into the passenger compartment. I'd use either these spacers that make use of the OE rubber engine mounts https://savvyoffroad.com/product/sav-mmltj/ or get the "Bombproof" motor mounts with rubber bushings at https://mountainoffroad.com/collect...f-motor-mount-kit-for-1-lift-97-06-yj-tj-lj-1

I'm no fan of Brown Dog's rubber bushing MML, too many complaints of their rubber being too stiff and passing vibrations.
 
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Jerry Bransford said:
A MML reduces the angles at the rear driveshaft similar to how a tcase drop does. For that size suspension lift a MML might be enough to eliminate the vibrations.

Just make sure to not use any MML product that uses polyurethane bushings as they will pass engine vibrations into the passenger compartment. I'd use either these spacers that make use of the OE rubber engine mounts https://savvyoffroad.com/product/sav-mmltj/ or get the "Bombproof" motor mounts with rubber bushings at https://mountainoffroad.com/collect...f-motor-mount-kit-for-1-lift-97-06-yj-tj-lj-1

I'm no fan of Brown Dog's rubber bushing MML, too many complaints of their rubber being too stiff and passing vibrations.
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Is there any chance any engine problems can occur due to change of angles?
 
TJim said:
Is there any chance any engine problems can occur due to change of angles?
Click to expand...

it's no more change in angle than a transfer case drop (unless I suppose you do both the drop and an MML).

But no, it's tilted back anyway, and that's the way oil runs to drain back down to the oil pan.
 
freedom_in_4low said:
it's no more change in angle than a transfer case drop (unless I suppose you do both the drop and an MML).

But no, it's tilted back anyway, and that's the way oil runs to drain back down to the oil pan.
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Thanks! No I am planning to do only one of them. Tomorrow I will lower the TC just as a test to be sure this is the problem.

I simply don't like the idea to have a lowered skid plate, but can't justify the costs for SYE, driveshaft, control arms at the moment, so MML seems to be a good alternative for now. If there are not any problems, I might give it a try
 
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TJim said:
Thanks! No I am planning to do only one of them. Tomorrow I will lower the TC just as a test to be sure this is the problem.

I simply don't like the idea to have a lowered skid plate, but can't justify the costs for SYE, driveshaft, control arms at the moment, so MML seems to be a good alternative for now. If there are not any problems, I might give it a try
Click to expand...
Yeah, just keep in mind the MML doesn't lower the output yoke as much as a skid drop does, so just because the vibes go away with a t-case drop doesn't mean that they'll go away with a MML.

In my experience, I started with a 1.5" TC drop, but installing a MML allowed me to cut the TC drop down to about 3/4". Once I regeared though, the vibes came back, and at that point I was ready to just say screw it and went for the SYE.
 
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freedom_in_4low said:
Yeah, just keep in mind the MML doesn't lower the output yoke as much as a skid drop does, so just because the vibes go away with a t-case drop doesn't mean that they'll go away with a MML.

In my experience, I started with a 1.5" TC drop, but installing a MML allowed me to cut the TC drop down to about 3/4". Once I regeared though, the vibes came back, and at that point I was ready to just say screw it and went for the SYE.
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Well, I hope a very small TC drop will solve this issue, since I don't have major vibes.

Thats why I bought many 3 mm (close to 1/8") washers in order to start with about 1" drop and start removing washers one by one.

I will know after tomorrow!
 
TJim said:
Hey everyone!

After lifting my TJ (3" front, 2.5" rear) I have some vibes.

Tomorrow, I am going to lower my TC's skid plate, with some washers and longer bolts, just to be sure that this is the problem.

I read a lot of threads that suggest MML as a mod to eliminate vibes and get rid of TC drop.

My question is if there are any problems caused by the MML. Even in a small rate. Any problems by changing the angles of the engine, transmission, transfer case?
Click to expand...
I installed a 1" MML to remove vibes after a 2.5" lift. It reduced them somewhat. The day I installed it I got DW. After going through some problem solving, I got it all worked out. @mrblaine said that a change in the relative position of the engine to the frame could affect rigidity or something like that. At any rate, after new tie rod's, a new trackbar, I only had a shimmy. After I got new tires, it was smooth as glass and has been ever since.
 
TJim said:
Hey everyone!

After lifting my TJ (3" front, 2.5" rear) I have some vibes.

Tomorrow, I am going to lower my TC's skid plate, with some washers and longer bolts, just to be sure that this is the problem.

I read a lot of threads that suggest MML as a mod to eliminate vibes and get rid of TC drop.

My question is if there are any problems caused by the MML. Even in a small rate. Any problems by changing the angles of the engine, transmission, transfer case?
Click to expand...
Are you talking about vibes coming at idle?because if you don’t use the stock motor mounts and blocks like Jerry suggest,you will get vibes at idle,when I went to brown dog I have vibes at idle but they go away as soon as you load the engine.
 
I had some additional vibes after my MML.
Always wondered if there was some measurement to check whether the engine and transmission were still in alignment with the frame and close to factory specs. side to side. More than enough play it the mounts for it to be cocked or pushed to one side.
 
Jerry Bransford said:
A MML reduces the angles at the rear driveshaft similar to how a tcase drop does. For that size suspension lift a MML might be enough to eliminate the vibrations.

Just make sure to not use any MML product that uses polyurethane bushings as they will pass engine vibrations into the passenger compartment. I'd use either these spacers that make use of the OE rubber engine mounts https://savvyoffroad.com/product/sav-mmltj/ or get the "Bombproof" motor mounts with rubber bushings at https://mountainoffroad.com/collect...f-motor-mount-kit-for-1-lift-97-06-yj-tj-lj-1

I'm no fan of Brown Dog's rubber bushing MML, too many complaints of their rubber being too stiff and passing vibrations.
Click to expand...
Just installed the above mentioned mountain off road product. Easy install. Smooth operation, ok maybe minor vibe at idle but i can’t be sure.
 
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Guys sorry, I wasnt taking about vibes at idle. I am having some driveline vibes at low speeds such as 10-30 mph
 
Jerry Bransford said:
A MML reduces the angles at the rear driveshaft similar to how a tcase drop does. For that size suspension lift a MML might be enough to eliminate the vibrations.

Just make sure to not use any MML product that uses polyurethane bushings as they will pass engine vibrations into the passenger compartment. I'd use either these spacers that make use of the OE rubber engine mounts https://savvyoffroad.com/product/sav-mmltj/ or get the "Bombproof" motor mounts with rubber bushings at https://mountainoffroad.com/collect...f-motor-mount-kit-for-1-lift-97-06-yj-tj-lj-1

I'm no fan of Brown Dog's rubber bushing MML, too many complaints of their rubber being too stiff and passing vibrations.
Click to expand...
If you get the brown dog mml.... be sure not to over tighten certain bolts.

There are specific instructions on that, and if you do overtighten... you will feel the vibes.

If you do it correctly, per instructions... it'll be good to go.
 
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