Celica 5 Speed Auto Tunnel

Driveline (including transmissions, differentials, tailshafts) discussion.

Celica 5 Speed Auto Tunnel

by NVMYEH » Sun Aug 09, 2015 2:35 pm

Guys i have been trying to find an answer on here regarding cutting the floor to fit a different type of gearbox. There is a bit about Supra box's but they are bigger in the body i think.
I have an Auto floor sedan and have a 18R 5 Speed Toyota gearbox (Celica) to go under it. Car has been fitted with a HR front end and when i got it, it had a 3 speed on the floor that was a side shifter type ( HT, HK??).
Do i need to trim the crossmember under the tunnel?? Also i have had my Crossmember modified by CRS to suit the bolting up of the box. I assume they make these to suit the correct height in regards to line up with the diff etc., as they informed me they had done 1000's and that all steel case Celica box's bolt up the same.
What lenght Tail Shaft do i need?? 1260mm center to center of Uni is what i have found elsewhere on the Web.
Can anyone shed any light on this for me??

Thanks in advance.
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Re: Celica 5 Speed Auto Tunnel

by utility8 » Sun Aug 09, 2015 7:01 pm

Before removing your current gearbox, measure from the centre of the output shaft up to the tunnel vertically above it. Record the measurement. When you fit the Celica box, you will need to replicate this measurement to ensure you've maintained the correct angle of the motor. You will need to modify the floor where ever it is required as the box goes in.
Do not assume CRS have the height correct........they have made many, many unhappy customers over the years. I bet they will say they have made 1000's of 9" conversions for EH's & not one has had a problem..........mine did. Short axle & I got told I built the diff wrong.......
One trick is to use the steel case from a Celice 4 speed & rebuild the 5 speed into it. This removes the hump at the front of the 5 speed case that will hit the floor.
As far as the tailshaft goes, put the box in, measure what you need then have it built. The old saying, measure twice cut once.
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Re: Celica 5 Speed Auto Tunnel

by NVMYEH » Mon Aug 10, 2015 9:03 am

Ok, the old gearbox is long gone now so measuring that is out of the question.
Might have to be a bit of suck it and see. They did use the same crossmember that held the old box in so it should be in the ball park if its not right.
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Re: Celica 5 Speed Auto Tunnel

by Ray » Thu Aug 13, 2015 6:29 pm

theory goes, the input and output shaft on the universal joints are to be parallel. the measurement john described will get you back to the correct angle.

if you are using a straight 6, then a angle protractor. or digital level (or iphone with app) should measure 6 degrees(from memory) thats 6 degrees sloping back from flat.

rais and or lower the rear of the box until you get the correct angle.
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Re: Celica 5 Speed Auto Tunnel

by NVMYEH » Tue Apr 26, 2016 5:29 pm


This info may already be on here but ill put it here anyway.
After some research i found that an LX LH Torana 6 cylinder tail shaft is the right length to put in the EH without having a alter length.
This is what i have used and it works a treat. I am using a Toyota R18 5 Speed gearbox
Just thought id let you know if you didn't already.
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