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Discussion Starter #1 (Edited)
Dumb question perhaps, but are the Opel automatic and 4-speed tranny bell-housings the same? Someone near me has an automatic bell housing that I would like to use to mate to a T-5 transmission. I understand that to use an S10 T-5 in my GT I will need to fabricate a 1" thick adapter to mount between the tranny and the bell-housing, but just wanted to be sure that the Opel automatic bell-housing would be suitable for that. TIA
 

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Dumb question perhaps, but are the Opel automatic and 4-speed tranny bell-housings the same? Someone near me has an automatic bell housing that I would like to use to mate to a T-5 transmission. I understand that to use an S10 T-5 in my GT I will need to fabricate a 1" thick adapter to mount between the tranny and the bell-housing, but just wanted to be sure that the Opel automatic bell-housing would be suitable for that. TIA
The Opel automatic transmission doesn't have a removable bell housing.
To make a T5 fit you will need a 3/4" adapter, not 1".

I'm one of the few people that have a T5 in my Opel GT.
 
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Thanks for the response. Looked like the car the bell housing came from was an automatic, and I didn't know any better.

Do you like the T5 well enough, or do you wish you'd gone with a Getrag?
 

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Actually the TH180 bellhousing is separate. It has a maze of grooves in the mating side for the fluid. You may be able to use it to adapt the T5 but would have to figure out the dimensions, mainly the depth of the bellhousing, because it is different than the manual bellhousing.
 

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The Opel automatic transmission doesn't have a removable bell housing.
To make a T5 fit you will need a 3/4" adapter, not 1".

I'm one of the few people that have a T5 in my Opel GT.
IIRC, Oldopelguy had some adapters made for the T5 installation several years ago. He installed one in an Opel before he sold his extras.

Harold
 

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IIRC, Oldopelguy had some adapters made for the T5 installation several years ago. He installed one in an Opel before he sold his extras.

Harold
Yes, I talked to him about them.
I believe he told me he still has one left.
 

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Thanks for the response. Looked like the car the bell housing came from was an automatic, and I didn't know any better.

Do you like the T5 well enough, or do you wish you'd gone with a Getrag?
I've never driven a GT with a Getrag so I don't have a comparison.
I like the T5 just fine but with I'd gone with a .86 gear ratio on 5th instead of the .73 that I have.
 

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Hydraulic release bearing. It only requires small holes for the hoses. Of course then you have to use a master cylinder as well.

Much easier to use a manual bell.
I know before,you will give this answer. But where to hell is the difference of cost then??????
T5 with all the mods or a Getrag 240 what is fit plugg and play.
 

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I agree the cost would go up if you went the auto bellhousing route. The manual one is the better choice, and the adapter has already been done. FO81 has a T5 in his car so may be able to make a drawing or have a batch made. Manta Part used to sell one years ago but I am sure they could be made cheaper than they sold for. $100-$200 maybe. There are a couple of S10 T5s on ebay for $4-450. They should probably be gone through with seals and bearings and synchros. They are 30 years old after all.

An alternative could be the T5 from later Mustangs, 2005-2010 V6. It is very short but with a fixed output flange that would require a slip joint in the driveshaft. The other potential problem I see is the height of the shifter box. FO81 might have a better idea if that is workable. The benefit is they are World Class and a lot newer than the S10 versions. The ratios are good except fifth is a lazy 0.68:1. Maybe it can be changed for a lower ratio from the T5 parts bin. You would have to use a Ford clutch disc and adjust the adapter thickness to fit the input shaft length.

V6 Tremec T-5 : 3.35 / 1.99 / 1.33 / 1.00 / 0.68, 3.15 reverse, 3.31 final

https://www.ebay.com/itm/Ford-Musta...282661022984?_trksid=p2349526.m4383.l4275.c10
 

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I have a handy dandy excel spreadsheet that will output final wheel speeds based on gear ratios of the transmission.
I'm willing to share it.

As for the mustang transmission, the reason the T5 is preferred is the location of the shifter. There's zero placement modification necessary although finding a good gear shift with the right angle to it can be problematic. I welded two gear shifts together and am very pleased with the result.

T5 transmissions are often available at a pick n pull wrecking yard for under $200.

As for the bell housing adapter, I designed my own and had it made.
The previous versions were cast aluminum whereas mine was made from 3/4" 6061 aluminum.
 

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I bought mine from the company "Manta-Part" Gil said I was lucky to get anything from them

it took like 6 months of me calling and calling to get the part (they also did Quad 4 conversions back in the day)





had to cut that slider thing with a hack saw





anyways T-5s in a Opel suffer from a lot of bad press mostly from people that never drove a GT with a T5 installed

I think the costs where like (back in the early 1990's)
$110 for the adapter kit (it was not cast aluminum)
$450 for the trans out of an S15 truck (but you can get them for a lot less)
$70 for the drive shaft (I really don't remember but I do remember my 700R to 66 Chevelle drive shaft cost $70)
$25 or so dollars for the trans mount (the Chevy dealer let walk in the back and find what I needed)

it was the best mod I ever did for the GT
I spent 2 or 3 years going to the drag strip every week and doing a ton of auto crossing

if you can get some type of 5 speed for you GT do it
its a very good improvement

Getrag or Chevette or T5 have all been done

edit; oh I forgot I been following this guys you tube channel (been looking for a close ratio gear set for the T5)

https://www.youtube.com/watch?v=XREsRG9Y1mU&t=1198s

David
 

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I have a handy dandy excel spreadsheet that will output final wheel speeds based on gear ratios of the transmission.
I'm willing to share it.

As for the mustang transmission, the reason the T5 is preferred is the location of the shifter. There's zero placement modification necessary although finding a good gear shift with the right angle to it can be problematic. I welded two gear shifts together and am very pleased with the result.

T5 transmissions are often available at a pick n pull wrecking yard for under $200.

As for the bell housing adapter, I designed my own and had it made.
The previous versions were cast aluminum whereas mine was made from 3/4" 6061 aluminum.
If you look at the picture in my post, the 05-10 T5 has the shifter box in the same forward location as the S10. It is taller because of the remote linkage to the shift lever, but I am thinking it might not be difficult to modify to have a lever come out the top. Since you have a T5 in yours, you would know how much room there is at the round hole in the top of the tunnel. I haven't been able to find a blown up view of the parts in that box, maybe it has the same shift block the older ones have.

The reason to go for this Mustang transmission is they are not 30 years old and beat on. Also the tail housing is close to the same length as the Opel 4-speed so no more short driveshafts.

An adapter is a fairly simple piece, concentric register holes and steps in the middle, the mounting holes don't have to be extremely close tolerances, they are just clamping things together.
 

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I bought mine from the company "Manta-Part" Gil said I was lucky to get anything from them

it took like 6 months of me calling and calling to get the part (they also did Quad 4 conversions back in the day)



anyways T-5s in a Opel suffer from a lot of bad press mostly from people that never drove a GT with a T5 installed

I think the costs where like (back in the early 1990's)
$110 for the adapter kit (it was not cast aluminum)
$450 for the trans out of an S15 truck (but you can get them for a lot less)
$70 for the drive shaft (I really don't remember but I do remember my 700R to 66 Chevelle drive shaft cost $70)
$25 or so dollars for the trans mount (the Chevy dealer let walk in the back and find what I needed)

it was the best mod I ever did for the GT
I spent 2 or 3 years going to the drag strip every week and doing a ton of auto crossing

if you can get some type of 5 speed for you GT do it
its a very good improvement

Getrag or Chevette or T5 have all been done

edit; oh I forgot I been following this guys you tube channel (been looking for a close ratio gear set for the T5)

https://www.youtube.com/watch?v=XREsRG9Y1mU&t=1198s

David
Yeah, I had trouble every time I bought something from Manta Part. I thought their adapter was more than that.

As far as the S10 trans, it is getting harder to find good used ones. They would have to be rebuilt, upping the cost. I have a Chevette T5 since 1988 that I was going to put in my GT but the shifter location held me back, then the project got put off. I was thinking if I could get a S10 tail housing, I could have the shifter box grafted onto the Chevette tail. The output shaft of the Chevette being shorter that the S10. There is one on ebay but the guy wants $300. That's halfway to having a 6-speed.
 

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I'm not sure but I was thinking the 05-10 mustang transmissions didn't have a removable bell housing.
 
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