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Something is slipping in 5th or and 6th

Marauderer

Marauderer

Grumpy Old Cur***geon
Messages
860
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Location
Powder Springs, GA
When towing my Travel trailer last weekend I noticed that going up hills on I-85 that the trans would slip. It did not throw any codes. When it started to slip I would immediately back off the throttle and reengage and sometimes it would hold and sometimes it would break loose again. I am suspecting that the 5th and or 6th gear clutches are slipping. I don't think it is the TC unlocking (different sound) as when it slips and you give it throttle it just spins more and doesn't accelerate. Should i get a code thrown if the transmission clutches are slipping?
 
Most likely your converter is slipping. The only clutch pack that 5th and 6th share is the C2, and in a 6 speed the C2 pack is pretty stout even stock. The C3's and C4's aren't the strongest, but my ex[erience has shown the converter to let loose before them. Whe nthe converter starts to go, it will feel just like a slipping clutch as it is just a single sided clutch that is being slipped in the converter during lockup. And it takes over 10 seconds of slippage in a 6 speed before it will throw a code for the converter, and 3 seconds I think and more than 50 RPM's of slippage to throw a gear ratio code. The converter is definately teh weak link in a 6 speed.
 
Since I am keeping the tune under 100 hp and have a TransGo Jr installed I can probably get away with a new Triple disc TQ? I was thinking of the PPE 1800 stall one. Comments and suggestions are appreciated.
 
If you have it out to do the converter, then I would at least open it up and have a look see inside. Some are running the LML converter for a budget unit, or the TRANSTAR single disc billet cover unit if your keeping the power down.
 
Therm, I know I should go in it and if I do that why don't I just install a Stg V kit and then be done with it for a while. As most guys it is all about the money. Not an inexpensive job. And I will have to get a trans jack also. I will look at some of the alternative TC options.
 
It's always best to put in a kit, but for the sake of 3 gaskets it would be a good idea to open it up and check the clutches in it. If they are good, I would put in a knock down valve to bump it up to 190 instead of 140 in lockup, a pump shim, and a converter. If you already have it out, it's the time to check it and see if the clutches are also gone or if it's just a converter. My moneys on the converter myself, but C3's can go, and C4's in the 6 speeds take alot of abuse.
 
Therm, thanks you are absolutely correct. That is what I will do. I need to start assembling my parts and get a Transmission Jack before I start.
 
So further review of TC's and I am now thinking:

Sun Coast GM Allison 1056 Torque Converter

Sun Coast Allison Pressure Regulator shim and tool 2001-2010

Sun Coast GM Allison Boost Modifier Valve 2004.5-2010

GM/Allison Torque Converter Bolts

GM Allison Tech Manual 2001-2010

Do I need to buy a specific Gasket kit or do they have the three gaskets i will need separately?

Also is there a better place to get the Allison Tech Man. for less than $47.

Also any recommendations on a transmission jack?
 
Marauderer, thanks for asking the question, I found the answers IF I upgrade my torque converter and with 50k on the clock it may be some time unless Murphy rears his head. Now I know why I subscribed to the whole section as sometimes I find the answers in a least expected thread title. Thanks Ferman for your invaluable information.....
 
Marauderer said:
So further review of TC's and I am now thinking:

Sun Coast GM Allison 1056 Torque Converter

Sun Coast Allison Pressure Regulator shim and tool 2001-2010

Sun Coast GM Allison Boost Modifier Valve 2004.5-2010

GM/Allison Torque Converter Bolts

GM Allison Tech Manual 2001-2010

Do I need to buy a specific Gasket kit or do they have the three gaskets i will need separately?

Also is there a better place to get the Allison Tech Man. for less than $47.

Also any recommendations on a transmission jack?
Click to expand...

Unless you plan on building the trans, I would hold off on the triple disc converter. If you get a good converter and put in it, then do end up burning a clutch pack, it could send debris through your nice triple disc and you end up getting it refreshed for a good chunk of change(around $1K last I heard). And if you do buy a triple disc, you might as well put a kit in it since the converter is the most expensive part of a built kit. With everything your buying, you might as well go ahead and get a GMAX kit for less than a $1K more and be done with it. I know you used to be able to buy a TRANSTAR billet single disc for about $400, and the LML is right around $385-400 last I checked VS the $1300 plus freight a triple disc is going to cost you. I would go with a LML or TRANSTAR if your not building the trans all the way if it were me, unless you plan on putting a full kit in it really soon. The extra $900 a triple disc is going to cost you just isn't worth it unless you build the rest of it to hold up as well.
 
I just want to be able to tow a trailer up to 15K lb. and not worry about it. I will be running stock turbo, injectors and planning on an EFI live tune of less than 100 hp.

Whadayathink??
 
Marauderer said:
I just want to be able to tow a trailer up to 15K lb. and not worry about it. I will be running stock turbo, injectors and planning on an EFI live tune of less than 100 hp.

Whadayathink??
Click to expand...

If you get a DSP5 with a tow tune of around 50-60HP, and a daily driver tune of around 90-100, then theres no reason to go with a triple disc so long as they are good tunes. I know some tuners out there make 100HP tunes with changes that can destroy even the best built trans, but a properly built tune won't hurt even a stock trans. In all honesty the best thing to do here is to open yours up and see how much damage there is. If all it is is a converter let loose, then either the LML or TRANSTAR would fit the bill for your HP goals. But if there is even the SMALLEST chance you may want to up the power later on down the road, then I woudl build it and be done with it.
 
I know my decision would be to stick with the stock trans and throw an LML converter in. You're just not giving the 6 spd anything more than it was built for.
 
I usually will roll the dice because the Scottsman side of me is a cheap ass (as my bride puts it so sweetly...:rolleyes:) and the Kraut side says OK, you'll probably wish you had paid once and be done with it but not to worry, I'll be there to say "I told you..."

:hihi:
 
Well, I ordered the Alligator Stg V kit with Alto clutches, Koleen steels, Sun Coast 1056 TC, and an MA Transfer case pump rub upgrade kit. I need to get a Trans jack and some manuals on remove/replace and trans instructions. Son is coming to help me pull it this weekend.

Any recommendations on manuals and Trans Jacks?
 
I used an ATSG until I got the ALLISON manuals. Be extra careful to properly check all your clutch clearances as the alligator kit is known to not just drop in out of the box. If you get your clearances off, it will not last long at all. And I don't know what all they include for the C2, but if it has 8 clutches I wouldn't run all of them.
 
I had heard that about checking the clearances in the clutch packs and I plan on doing that. I may have to get some shims but I will cross that bridge when i get to it. I do know that Sun Coast is doing the Alligator kit now and it should be pretty good.

Now to get a good trans jack to use in the driveway.
 
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