3x00 5 speed drivetrain alignment

[3400beretta]

I'm having some drivetrain alignment issues that are driving me nuts. Car is a 94 Beretta that is now a 3500 5 speed. Originally was a 3100 auto. I am using the new 94-96 style mount setup.

I have cut and rewelded the top mount 1" back. I have drilled a new hole 1" forward for the dogbone mount. Mounts are welded in the right spot on the transmission side. I have a FFP dogbone, poly insert in the upper, and I made my own 94a poly transmission mount inserts. (I have the 2 circular trans mounts). In other words, my drivetrain does NOT move.

Looking from the side of the car into the inner fender with the wheel off, where the axle comes out of the transmission is not directly in line with the wheel hub. It is the same situation on both sides. Where the axle comes out of the transmission looks at be at least 1/2" or more offset towards the front of the car. I believe the transmission output should be in line with your wheel hub.
This is hard to explain, so I drew a quick picture. It is from the passenger side view, with the axle removed.

Now heres the thing, I decided to check my daily driver, also a 94 beretta, but still a 3100 auto. Looking from the same angle, the transmission output is almost directly in line with the axle hub, as it should be. In other words, with the wheels pointing straight the axle is nearly straight (horizontally) from where it comes out of the transmission, to where it goes into the axle hub.

Now here are my questions. Keep in mind that my car is an L body with the newer 94+ 3x00 mount setup.

1. We all know that in the older cars (92-93), there was a 1" difference in upper mount orientation in an auto vs manual car, remedied by two different "T" pieces. However, with the 94+ mount setup, how can we know for sure that it is exactly 1" still for the upper mount relocation in an auto vs manual car? Since there was never a 94+ 3x00 manual car, I believe this to be an assumption made by someone.

2. Is it okay for the axle output to be horizontally offset from the axle hub like my car is, as long as both sides are the same? In other words, as long as the drivetrain isn't twisted, is it hard on the axles? Has anyone else noticed this on their cars with the same setup as me? If you think about it, the transmission output will be offset relative to the hub in a vertical sense, depending on the ride height of the car. Or is there a tolerance for this?

3. I have now found that there are 2 different part numbers for the lower dogbone in the 92-93 cars, depending if it was auto or manual. Does anyone know the difference between these two dogbones?

[IsaacHayes]

Do you have the 3100 and 4t60-e from the 94 still? Bolt them up, measure how far the axle comes off of a reference point of the block. Then measure on the 3500 to the axle output of the 5spd. That will tell you how much we need to move the drive train back..

I have the exact same setup as you. 3400/93 5spd. But the passenger side is not yet moved back. I'm thinking of the custom T-bone piece instead of cut and weld the mount now. Takes longer to make then cut/weld on the black mount, but if you think about it the T-bone is more equal distribution of weight instead of at the back, and the black mount on the body won't change the pressure point either. It will still be pressed down in the same factory spot, possibly keeping it's strength....

I will be addressing this as soon as I have a house and a garage where I can walk on either side of the car rather than squeezing by and crawling out the window.... Hopefully that will be soon...

Woody90gtz needs to chime in, but I don't think he is on here... He has 87-91 trans mount but still we can get an idea.. I can't recall if he has the the 1" shorter dogbone I had Forced_Firebird make or not when we did the L body rebuild-able poly dogbones. I know KLFO has one. He swapped his 92 to 5spd but you can't use the 3.1 mpfi engine t-bone bracket on a 3x00 so I don't know what he did for alignment on that side..

3) no idea, but I know the 92-93 dogbone bracket on the motor has a hole for both A and M... Maybe the dogbone was .5" shorter and the hole was 1" totaling 1.5"....

EDIT: Can you take out your torque strut and see where the passenger side rests? Does it help then? If you think about it, if the dogbone is too long, that can cause a rotation of everything and move the axle downward and forward. It may be possible that it's twisting both sides too. How hard is to get the dogbone in and aligned? Does it drop right in, or do you have to fight it some?? Are your 92-93 trans mounts filled or custom something else? Got pics? It's possible that the stock rubber allows the drivetrain to settle in to the right place especially with a rubber dogbone...

I have a trans bracket and dogbone from 87-91 I will be putting on when I get a 87-91 drivers side subframe. So I will have dual dogbones. I can try just that dogbone and see how the drive train rests (after moving the upper passenger motor mount back 1")...

Like I said above, it could be the top mount was 1" shorter, and the dogbone 1.5" shorter total with the hole and dogbone itself...


For others & reference here is a pic of a 3100 dogbone setup..

[3400beretta]

Maybe the dogbone was .5" shorter and the hole was 1" totaling 1.5"....

This is exactly what Im thinking. Funny thing, is that the 92-93 manual dogbone is the same part number as the 94 (only) auto dogbone. So I'm going to measure the one on my other car and compare it to my FFP dogbone.

No, I do not have the original 3100 and 4t60 from this car. I was trying to measure things off my daily driver car, but its hard to pick a spot to reference from. The fact that the 3500 and 3100 aren't identical doesn't help either.

Again, since I do not know for a fact that the upper mount needs to be relocated 1", dishing out $70 for the MRZ "T" piece seems like a waste of money to me.

I'm also wondering something. What if the drivetrain is a bit offset on the 5 speeds from the factory. Don't forget, with stock rubber mounts, there is a fair bit of play, and I'm sure they didn't want the alternator smashing into the blower motor, as it would get pretty close. So perhaps this was a lesser of two evils, a compromise. If thats the case, then having it perfectly aligned would definately be benificial, and prolong the life of the axles, especially at my power level. I may be onto something here...

[IsaacHayes]

I added more stuff all over to that last post. Re-read it to make sure you didn't miss something.


Think about this, what if everything moved 1" back (trans side welded up correct, upper engine mount T-bone 1" back), but they ALSO tilted the engine differently. Maybe rather than moving everything back 1.5" total, which might get things too close to the fire wall, they had it 1" back, with a tilt pulling the bottom of the engine/trans back to align the axles .5" more, and the top of the motor forward.

What do you think? Maybe we are thinking only on X-Y and need to think about rotational alignment too... Cause as it sits with yours (and probably mine) when you get on it, the axles are going to move even farther forward if the mounts have any give...

The difference in dog bones maybe the aluminum vs steel ones though... I have not measured the length on the steel ones though. Never had my hands on one...


As far as the custom T-Bone, I hear you. I'm just saying if/when I move the upper back 1", I think now I'm going to make/get a T-bone moved back 1" rather than take the easy route of cutting/welding the mount. Not only will it put the weight more in the center of the T-bone but the weight coming down on the black mount will be in the stock location instead of rearward more...

EDIT: read the last bit of your paragraph there and you came up with the same thing I was typing as I was reading your post...

I think we are on to something...

[3400beretta]

Yeah, I hear you on the rotation thing. The thing is though, the transmission side mounts will only allow so much rotation. My mounts are totally redone (not just filled) with shore 94a poly, which is basically as hard as a rock. There is no give, and if I force anything to move, it will only bend my mount brackets.

As far as the dog bone, there is yet another part number for the 95-96 auto cars, for a total of 3 different variations.

When I took the "T" piece off the upper mount today, the engine wanted to move towards the firewall about 1/4 inch. I think tomorrow I'll take both the "T" and the dogbone off and see what happens.

BTW that stupid mount wasn't easy to cut and reweld. I just didn't want to dish out $70 bucks on the "T" piece, nor wait for it to show up. I do agree with you that it would be better to leave the mount alone, and make/modify the "T" piece. I think I will have my own "T" piece made up once we figure this thing out.

[IsaacHayes]

Post up the part #s. .. The 94 auto and 95-96 may be the steel vs aluminum ones. My 94 had an aluminum though.

Did you support the engine when you took the T-bone off? Cause it would drop down without that of course... LOL

I don't want to dish out $70 either, as the shipping from Canada will be big chunk added on top of that as well coming to the US. I plan to make my own or have one made.

Sucks that you are committed with the poly. That's why if I fill my mounts I will make sure they are fresh and in the right spots and not sagged first and that everything is perfect. This 95 car though rides so smooth compared to my 94 (same suspension though) that it must be a solid car and I don't want to add vibrations as it's sooo damn nice and smooth. So I plan on adding extra torque struts with poly bushings, and leaving the mounts that hold everything up alone other than the poly engine insert. The poly dogbones don't add vibration as it's not an automatic but hopefully having two will keep rocking down. I don't plan to slam the gears too hard on this thing.

What is done to your 95-98 style upper pass engine mount? Just the prothane poly insert? Did you ever bolt up the top bracket to it? BTW did you know you can get replacement rubber for them, that is not fluid filled? Might want to do that, as they mount can sag and throw things off (my 4t60-e trans mount was sagging like a mofo). Also if you think about it, getting on it hard twists that mount and pushes down in the back, which can make it sag at an angle and that could be contributing to the wrong rotation of the drive train... I'd grab a solid rubber center replacement and throw that in there with the prothane insert and see where you are at... I know the rubber in my 95 looks great compared to my 94 which the mount that is in it came from a 95 grand am with over 100k, and I added at least that to it. (the 94 mount was way worn out at 100k, so I went to 95+ style years ago)

[3400beretta]

92-94 man trans - 22595753
92-93 auto trans - 22637875
94 auto trans - 22595753
95-96 auto trans - 22145939

Yes I supported the engine.

The poly mounts I made are definately all centered, however the car vibrates like a mofo and I'm wondering if they are a little overkill. I'm thinking about trying these inserts: http://www.carcustoms.net/product_in...roducts_id=331

BTW, on my old car (3400/5spd), the first thing I did was add the FFP dogbone, all the other mounts were stock. It definately added vibration to the car.

Yes I got the top bracket bolted in. I only have the poly insert in the upper mount. Where can this solid rubber mount you speak of be found?

[3400beretta]

A little update.

I checked the parts car today - 93 2.2/5spd

Same shit. The transmission output is offset towards the front of the car, about the same as my 3500/5spd car.

So that means its like that from the factory.

[3400-95-Modified]

So that means its like that from the factory.

I'm not surprised by this and it shows the reason why people were breaking axles before so easily even with a stock 3400... Just think, add one MORE inch to that miss alignment and then the situation just gets worse.

As you said it was probably done to clear the firewall as far as the alternator position goes for the V6's... Now on the 4 cylinders, who knows, maybe thats a downfall of mass production, all models suffer.

That was a nice drawing... Next time you should put a directional arrow for the front of the vehicle... LOL

I wonder what my 4t alignment looks like... I'll have to pay attention when I put it all back in.

[Weatheralls Auto]

With the Torque, would it not rotate back into alignment? (atleast in design)

If making Solid, or near solid mounts, you may want to take that into consideration and build in a little rotation.

[Weatheralls Auto]

I'm not surprised by this and it shows the reason why people were breaking axles before so easily even with a stock 3400... Just think, add one MORE inch to that miss alignment and then the situation just gets worse.

As you said it was probably done to clear the firewall as far as the alternator position goes for the V6's... Now on the 4 cylinders, who knows, maybe thats a downfall of mass production, all models suffer.

With stock (sloppy) mounts, if they were built to line up, under heavy torque the engine may rotate that much to the opposite causing broken axles?

One you stray away from stock there is a lot more to consider. Not just replace with stiffer stronger parts I guess.

[3400beretta]

With the Torque, would it not rotate back into alignment? (atleast in design)

If making Solid, or near solid mounts, you may want to take that into consideration and build in a little rotation.

This is EXACTLY what I was originally thinking. But since my engine does not move at all, this is not the case for me.

And Jon, as I found with my 94 3100/4t60 everything is nearly lined up. I'm sure you'll find the same with your car. It is off just a tad towards the front of the car, but nothing compared to the 5 speeds.

[IsaacHayes]

Rodney, strange, the orange car has a FFP dogbone and it doesn't vibrate one bit, even when slipping the clutch, but it's got a stock clutch I'm pretty sure. Certainly not a puck style. Maybe the body is just really solid which I figure it is as the suspension is smooth even with ebiachs/etc. Did yours vibrate in neutral with the FFP?? Maybe your other mounts were worn and that contributed to it? Or maybe the orange cars drive trains is pre-loading the mounts since the passenger side is not moved back 1" and that some how takes out vibrations and movement?? lol

$49 Autozone, P/N A2803 DEA brand. Front passenger side Insert only - Solid option

http://contentinfo.autozone.com/znetcs/product-info/en/US/anr/2803/image/8/

You drill out the bottom "riveted" mount, and then bolt this into the black metal frame.

Other parts stores probably have them. Look up 95 3100 berettas online at their sites.



So the stock position for the axles is .5" IN FRONT of the hubs?

Jon & Rodney & Planethax:

Ok when you get on it then, it is only going to move MORE in FRONT of the hubs.. Not back into the center... And the top of the engine is going to move MORE into the fire wall causing alt/blower fan interference.


Rodney, you may want to forget about the stock alignment and go for more of a centered alignment like the 4t60-e setup just to take stress off the axles at your power level. Even though your "solid" setup won't move much, it still isn't centered as is... And yeah 94 poly might as well be solid...

You may want to try drilling holes into your poly like the car-customs mount has first to see if that helps. I'm sure the prothane mounts with holes they sell are not quite 94 shore though, but still some holes will help to let it give a little more with your 94a. Are we sure those prothane cavy trans mounts even fit?

Also think about this, you want stiff mounts to prevent over extending of the drive train, but by going very stiff or solid, you take out any give in the drive train. This puts more stress on parts and takes away any cushion from shock loads, which will snap axles and break things. Tires spin then bite hard and there is no give in the mounts to absorb that shock, it goes right to the axles and snap... Also by not having a little give, it does transfer more power to the wheels, but at high power that can possibly be the threshold between the tires breaking free or not....

Solid/super stiff mounts may not be not the end all answer. They may be fun for a stock car without axle snapping power or traction issues, but when you throw a ton of power in the mix then you switch from an engine movement problem towards tires breaking free easier and axle snapping issues..

I want traction, so instead of having solid mounts and tires that break away before the axles do, I will leave some give in the mounts and go with some really sticky wide 245 tires...