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Discussion Starter #1
My issue is I believe the Synchro's are giving up on my stock Aisin AR-5 Transmission. My Car is a LS2 powered Mallet Conversion early 2006 Build (November 2005) so from what I have been reading it will have the early Synchro design. My problem is the car is Stock as it came from Mallet and I would like to keep it that way, so I don't want to replace the transmission, but just rebuild it with more durable parts.

Does anyone know of a rebuilder with experience with these transmissions? I am aware of the more durable carbon fiber synchro option that was used in the Hummer H3 version of the trans.

The car has about 23,000 miles on it, and the 2-3 shift is getting difficult unless I double clutch it, but that does not help acceleration. I did drain and replace the fluid with Royal Purple 70/90 full synthetic about a month ago. It has helped but not eliminated the problem.

I believe the Trans was having issues when I bought it, as the car would "jump" a little when you came to a complete stop, then placed the shifter into 1st gear. Now the other symtoms have arose.
 

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Are you certain that you don't have a clutch problem? A jump going into first gear sounds like a partially engaged clutch, since something has to be turning to cause the jump. I have also noticed that shifts are a problem when I don't fully depress the clutch, and that would translate to your 2-3 problem.
 

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Discussion Starter #3
I have thought of that, but in the past if I had a clutch issue it would be in every gear change, there is no burned clutch smell that usually goes along with a clutch not disengaging fully. Also Double clutching never effected the shifting when it was a clutch issue in the past.

But this is my 1st Kappa so they may be different than the other cars I have owned.
 

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Your description suggests a hydraulic problem. Rebleed the clutch and look for leaks or weeps. Inspect the MC. It may be letting go with the pedal depressed. The slave is not accessible until the engine or trans come out. In my Ls/Tremec conversion there is no access to most of the bell housing bolts; and a forward sliding pull of the engine trans package is necessary to expose them. I hope your Mallet swap allows you easier access.
 

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The jump when engaging first at a stop is almost certainly caused by incomplete disengagement of the clutch, although it could be a galled pilot bushing. There is no way a synchro can create motion when the car isn't moving.

Unless you are losing fluid a hydraulic problem is most likely either the master cylinder or the clutch pedal return spring. A leaking master cylinder will normally allow the clutch to slowly engage while you hold the pedal down, but that is not absolute. A weak or broken pedal return spring will prevent a full charge of fluid in the master cylinder, resulting in incomplete release of the clutch. This recently happened to my RL.

The stock hydraulic system is self-bleeding, with no provision that I know of for any manual bleeding.
 

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Discussion Starter #6
I will inspect the return spring when I get a chance, I may be over describing the "jump" it is more a feel in the shifter and the car does roll slightly when the shifter engages 1st gear. I have never had a manual trans car do that before, and I have been driving them for 30+ years.

I am not ruling out a clutch engagement issue. Just for complete info I did have all the fluids replaced this spring by my favorate ex Pontiac dealer and it did not effect the issue, it has grown gradually worse, and seems to be worse before the trans gets up to operating temp.

I have not seen a loss of Fluid to the brake system so I don't think there is a leak, I have not noticed the clutch slowly engaging with the pedal held down.

But I will check the return spring as soon as I can.

Thanks for the tips.
 

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The pedal is returned by the pressure plate diaphragm spring via the oil in the system. The pedal does not have a spring to pull it back.
 

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The pedal is returned by the pressure plate diaphragm spring via the oil in the system. The pedal does not have a spring to pull it back.
Mine does. The 2.4 has one, the RL has that one plus another of a different style.
 

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I just want to say that my car exhibits a slight roll forward when put into gear as well. I've always attributed it to the gears meshing and causing just a tiny bit of forward propulsion. It also just so happens that my synchros are nearly dead, so I await an answer to the initial question.
 

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No clutch dragging or gears grinding here, just an occasional slight roll forward when going from neutral to first without the brake applied and the telltale feel of worn synchros. It has done the same with the stock clutch and a new SPEC Stage 3+.
 

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Discussion Starter #12
No clutch dragging or gears grinding here, just an occasional slight roll forward when going from neutral to first without the brake applied and the telltale feel of worn synchros. It has done the same with the stock clutch and a new SPEC Stage 3+.
I believe we have the same symptoms, but if I get a chance Friday I will take the car to my buddies trans shop and get his opinion of what the issue is, he should at least be able to rule out a clutch disengagement issue. He has never worked on a Kappa of the Aisin transmissions so I don't know how much help he will be about internal trans issues. He mostly deals with newer automatic's & building T350 & T400's for drag racing and Higher HP street use.
 

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Find a nice flat concrete pad that is as close to level as you can get (gas station filling areas are good). put it in gear with the clutch pushed in all the way - if it pulls forward at all you have clutch drag.

EDT, it doesn't matter what the gears are doing, without some clutch involvement it can't result in any motion to the car.

If it does move, then insufficient clutch travel is usually from hydraulic adjustment, air in the system etc. Or it may be in some failure mode.

This is why I hate cars with HTOBs. Instead of a 15 minute external slave change it means the engine coming out.....

I get into that argument all the time with the MG engine swapping guys. They usually use HTOBs as a matter of course and I tell them that every single component of a car WILL fail at some time or other, and it is just good planning to choose a fitment that minimizes the effort when, not if, that happens.

Sometimes you don't have much option; I haven't examined the tunnel area of a Kappa to see if there is room for an external slave.

Even when the HTOBs don't fail, they can be a real swine to bleed!
 

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Agreed with all points.

There is no provision for bleeding the clutch hydraulics. The system is self-bleeding after (in my case after replacing master cylinder) five or six full pedal strokes.
 

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Discussion Starter #16
Well I did take the car to my buddies shop, and another that he recommended and their opinion is that I do have a syncro issue, they both concluded that the clutch is fully disengaging and that the issue I have is internal to the transmission. But both shops do not have any special tools required ( if any ) and have never rebuilt one so they did not want to take on the job of rebuilding it.

So I guess I am back to my original question, does anyone have a suggestion on where I should send the trans for a rebuild/upgrade?
 

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Well I did take the car to my buddies shop, and another that he recommended and their opinion is that I do have a syncro issue, they both concluded that the clutch is fully disengaging and that the issue I have is internal to the transmission. But both shops do not have any special tools required ( if any ) and have never rebuilt one so they did not want to take on the job of rebuilding it.

So I guess I am back to my original question, does anyone have a suggestion on where I should send the trans for a rebuild/upgrade?
Have you tried a local shop that specializes in transmissions? You are talking about a synchro replacement, not rocket science. Any transmission shop worth half its salt should have no problems doing it, especially since its a common truck trans, based on another popular transsmisson. I did a quick google search of "transmission shop" and your town listed in your profile. I would give "Accurate Transmissions" a call. In the google reviews they look good, and several people have commented they have done transmissions on their race cars. Couldnt hurt to call, and tell em whats up and see what they have to say. Plus you will be supporting a local small shop, and thats always a plus!
 

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Discussion Starter #18
Unfortunatly that is my buddies Transmission Shop, Sorry if I did not make that clear in my last post.

Unfortunatly he usually works on Automatic's and older Muncie or BW manual transmissions, He even does T-56's but aparantly he is not up for learning a not very common (in our area anyway) manual trans. I would be interested to know how many Colorado, Cannon, or H3's were actually built with the 5-speed manual. The other issue he has is my car has a LS2 V8 and he said he is leary to do it and have the same issue occur in a few thousand miles,

But thanks for the response, and the time it took to look the info up.
 

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Unfortunatly that is my buddies Transmission Shop, Sorry if I did not make that clear in my last post.

Unfortunatly he usually works on Automatic's and older Muncie or BW manual transmissions, He even does T-56's but aparantly he is not up for learning a not very common (in our area anyway) manual trans. I would be interested to know how many Colorado, Cannon, or H3's were actually built with the 5-speed manual. The other issue he has is my car has a LS2 V8 and he said he is leary to do it and have the same issue occur in a few thousand miles,

But thanks for the response, and the time it took to look the info up.
Okay so in that case, maybe I would check the supra forums and see who mk3 (not mk4) supra guys go to for trans rebuilds, I know it seems strange to ask another car specific forum for info, but the it couldnt hurt to try.
 

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Like honestly, Ive thought about it, and rebuilding your transmission is probably not the way to go. You probably will run into synchro issues shortly again. Why dont you want to go to a t56? or a Getrag from a supra? or any other number of transmission options out there? Its probably going to cost you less in the long run, and you will end up with an extra gear and better ratios in addition to a stronger trans/clutch.
 
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