T56 rebuild?

eaks

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Hey all

I've had my mamba srt10 for just over a year.. Car has 42k miles on it and seems to run pretty well.. Since I purchased the car it has had issues going into 6th gear. It doesn't grind but it simply won't go into gear for a couple seconds. It does seem to go in a bit better when double clutching but not sure if it's just the extra delay from the double clutch or if it is actually helping out.

I am planning on installing a Paxton blower this fall/winter and am considering also pulling the transmission and having a look at it. I am mechanically inclined and will be installing a 2nd 4 post lift in my garage this weekend. Do you think a t56 rebuild is doable and what are the recommended rebuild kits (most I've seen online are people who rebuild and not actually selling kits). I plan to make 650-700whp so not sure if different gears are required or not ( would expect not).. I also like the 6th gear overdrive for getting some what acceptable mileage on the highway and don't mind the current gearing.

Do you think it's just a synchro on 6th that is my issue or something else?

Thanks all
 

Goggles Pizano

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If you search, you will also come up with the Gen3 diff is weak too.

And there are rebuild kits available all over the web for the tranny.
 
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eaks

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I was able to find a couple different rebuild kits (after posting this) but more curious what would be recommended with upping the power to the ~700whp levels). Suggestions on diff for this power level?

Also curious if anyone has seen a similar issue with 6th gear and corrected it?

Thank you
 

Old School

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I don't know the limits of a T56, but I replaced mine with a TR6060 from a Gen4. It's close to a bolt in.
 
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eaks

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Link for the 700HP rebuild kit?
Not sure if you were asking me. I am unsure what power levels these rebuild kits handle which is why I was asking for some support/knowledge from the group.

I found this rebuild kit:

I will reach out to companies closer to when I am ready to do this but was looking to get some info prior. The price of a tr6060 doesn't seem too outrageous and since I dont have issues with my trans (outside of the getting into 6th gear as noted above) if I dont get some reliable information I will most likely just run the car as is and if I have issues budget for a new tr6060. If I get some good information or when I start to reach out to the companies providing the rebuild kits I may still go that route this fall/winter.

If anyone has any additional information or details I would love to hear it.

Thanks everyone
 

Stan Wilson

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Eaks,

A T56 will not hold up to your power plans. Trust me. I had two built T56 boxes. I lost 4th gear in both transmissions in one weekend at Daytona. The gear set is weak. My car only made 625 RWHP. It stripped the teeth off of both T56 fourth gear sets. I replaced the T56 with a T6060 and the shorter driveshaft at the track. I never had another issue. The T6060 is the only way to go unless you enjoy dropping T56 boxes out of the car each time you really drive hard. Order a T6060 and the shorter driveshaft. You will not be disappointed.
 
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eaks

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Eaks,

A T56 will not hold up to your power plans. Trust me. I had two built T56 boxes. I lost 4th gear in both transmissions in one weekend at Daytona. The gear set is weak. My car only made 625 RWHP. It stripped the teeth off of both T56 fourth gear sets. I replaced the T56 with a T6060 and the shorter driveshaft at the track. I never had another issue. The T6060 is the only way to go unless you enjoy dropping T56 boxes out of the car each time you really drive hard. Order a T6060 and the shorter driveshaft. You will not be disappointed.
Thanks this is the exact information I was looking for. Not great news that I may need to go the t6060 route but there is no sense in dealing with the stock T56 (and spending to rebuild) so I will use it as-is and I will budget for a T6060. All that is required is a shorter driveshaft (any details on the measurements or a company to go with)? The bellhousing and everything will bolt right up?
 

Old School

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When swapped my T56 for a TR6060, I used a Gen4 driveshaft. But only the yoke is different, driveshaft is the same. I also spaced the slave cylinder with this:
 
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eaks

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Doing a bit of research on the tr6060 and surprised to see it is only rate at 430tq (430-650lb-ft depending on gearing).. This is a surprise to me as that doesn't seem too crazy..

Found some crate trans tr6060 for 5-6k cdn which doesn't seem horrible but again I want to make sure when I get my blower on if I have any issues with the stock trans I know what to go with when it let's go.
 

MoparMap

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I think a T56 is a plenty stout unit, but a lot of that comes down to the tune and how it's driven. There was a local guy here that made 1100 hp to the tires on a stock T56 in his gen 2 for years with no issues, but he knew not to do clutch dumps and other silly stuff like that which would be extra ******* things. If you roll into the power and preload stuff before you really pour it on they will last a lot longer.
 

99RT10GTS

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Eaks,

A T56 will not hold up to your power plans. Trust me. I had two built T56 boxes. I lost 4th gear in both transmissions in one weekend at Daytona. The gear set is weak. My car only made 625 RWHP. It stripped the teeth off of both T56 fourth gear sets. I replaced the T56 with a T6060 and the shorter driveshaft at the track. I never had another issue. The T6060 is the only way to go unless you enjoy dropping T56 boxes out of the car each time you really drive hard. Order a T6060 and the shorter driveshaft. You will not be disappointed.

Stan!!!
 

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