Upgraded Auto Internals

[Babylon6]

Hi guys. I own and run a GT-A so forgive the intrusion :)

Has anyone done any work on the internals of the auto box or looked at other mods such as new torque converters or bigger pump, lines etc?

Been digging around and there seems to be a fair amount of stuff that can be done, especially if you can get stuff to the US.

[bradc]

A couple of the smarter guys on ozvr4 have looked into upgrading a few internal parts that tend to break. I don't know of anyone that has played with different pressures, torque convertors or anything like that.

[Kieran]

Been digging around and there seems to be a fair amount of stuff that can be done, especially if you can get stuff to the US.

AFAIK no-ones touched them over here. But as you say, in the US they've been beefing up the autos they have (F4A31/32 and I think now the F5A51?) for some time.

Maybe the way to approach it is to find out the model numbers of the boxes they can upgrade, find the nearest match to ours (W5A51), and then start comparing part numbers and such - for example, if there's a set of upgraded steels for, say, a F5A51, then it might be worth seeing if they'll fit ours?

[bradc]

The internals of the F5A51 are identical apart from the very last shaft which gives power to the transfer case on the 4wd version

[Babylon6]

Been talking to a guy in the US - IPT Transmissions who does a complete build of the box. Pity its so heavy and so far away. cost a kings ransom to ship, tax etc.

closer to home Scott Lowe will do some sort of build thats rated to 500bhp. Costs around £3000 and not sure that even covers remove and refitting of box. Make a great 1/4 car though ;)

[Babylon6]

Bit of progress here for anyone thats interested. Have sourced a custom build torque converter with a high stall point, brazed fins etc in the US. Its 950 usd including shipping so its gonna be on its way to me soon and then over to Eurospec for fitting.

Also looking at a valve body refurb. Need to establish if its the same on the VR4 and GTA as the Evo box is like gold dust. Anyone know?

[eyeballprawn]

Do you have any more info on the t/c, such as stall speed and where you sourced it from?

[Babylon6]

IPT in the US.

http://www.importperformancetrans.com/mitsubishi_dsm_transmission_modifications.shtml

The one they are building for me will be 3600 stall.

[eyeballprawn]

Cheers, I didn't realise you were getting the t/c from the same place. Sounds like an interesting project.

[Nutter_John]

whats the stock stall speed ( 2000-2500 ???? )

3600 should give you some real nice drag times but may make it a rougher ride on day to day

[eyeballprawn]

Stock is 2100 - 2600rpm, much above 2800 usually makes it a hassle for everyday road use. So be sure to let us know how you get on with it.

[Babylon6]

Oops - I meant 2800 - sorry. The 3600 relates to something else.

There is some good reading to be had on this Aussie site as well - http://www.acceleratorhighstall.com.au

[Kryton]

Did you ever do this & did it work?

[Babylon6]

Hi - yes - I did this a long while ago. since blown the box up and replaced it again :)

I would not bother going for a high stall converter unless you really want to get into drag racing as its a pain in normal use. I am looking into a UK supplier for torque converter work at minute as it saves a lot of hassle. been quoted 300+Vat for a restall/braized fins and kevlar OWC.

I used IPT for my work and parts. There's a few guys - cobraTransmissions, Wittrans and Sheptrans who can supply you rebuild kits. Really depends what you want to do. What is up with yours?

[Kryton]

I don't know exactly to be honest as it only went Saturday night but after draining the ATF & seeing how much metal was in it, i'm guessing I will need a new gearset at least. So what parts were included in your kit from IPT?

[Babylon6]

Did you lose drive or develop a fault? If its still able to move, does it crunch?

When you dropped the fluid, was it full of metal filings or were there chunks in it, like gear teeth? If its got teeth in it then you have lost one of either the direct drive planetaries or the overdrive planetaries. Wheel hop is a killer of this box.

IPT will make you a kit up depending on your needs. The basic overhaul kit has o rings, paper gaskets for oil pump cover and valve body, plastic rings, internal filter, cork sump gasket, seals and I think a replace upgraded wave spring. Rverything you need if you were to striup the whole box.

You can then go for a banner kit, which adds on replacement clutch friction rings for all the clutch packs. Theres loads of them. The full monty is a banner plus steels, which you may or may not need, depending on issue. I have seen one engine that needed rings and another that didnt.

Like i said, I will be ordering one this week so can let you know costs. Its about 300, 400 or 500 USD depending on kit.

Who is doing the work?

[Kryton]

Ok thanks for the reply. It will be a mitsubishi mechanic doing the work. It did drive a maximum of a couple of feet in both directions & crunch at the limit but now doesn't move at all. The fluid had lumps or metal & smaller shavings. It was fine & went unexpectedly, no symptoms :(

[Nick Mann]

My guess would be a planetary tooth mash up. You can have that with not much large metal on the sump plug magnet, simply because there are no large pathways out of the inside of the planetary until you strip the box. Movement would be the planetary operating on it's remaining teeth until a broken tooth locked movement again. Eventually something will rip the rest of its teeth off and stuff in there just spins, no more propulsion possible. This also accounts for "rotational locking" when the car is being pushed - it's the same issue of planetary teeth fragments locking between good ones.

[Kryton]

Ok good to know. I will strip it anyway once I've got mine running to see what can be done with it. I do still prefer the auto but this really will restrict how much boost I can run through one

[Babylon6]

What Nick said. I would add that there are 2 sets of planetaries - one behind the side casing and one in behind the diff. I would lay money that its the one behind the diff (direct drive gearset). Either way your transmission will need to come out and be thoroughly cleaned out. Got 1 sat in garage in this state and 1 at Eurospec. Hope your mitsi mechanic is a friend as this is a couple of days work to drop the trans, strip it and replace.

You are meant to junk the converter as well, or get it opened and cleaned out. Martin Lowe in Barnsley can do this. Oh and if you have any coolers then they are likely full of crap as well so they will need flushing.

I got loads of photos on Facebook of the dead planetaries if you want and idea of what has happened. https://www.facebook.com/media/set/?set=a.10151274595820579.518882.540105578&type=1&l=c64e79468b

If its the planetary behind the side casing I should have a spare one you can have if you want to try and rebuild.

[Kryton]

Really appreciate your help. The mechanic always gives me favourable rates so that's not the end of the world. I will keep you posted if ok? Do you have any other parts kicking around to rebuild that you want to sell if this is the route I go down?

[Babylon6]

I got most of a VR-4 box, which you can have if you need bits. A drink and postage is fine :) Only bit I dont have is direct drive planet as thats what went on mine.

Change the wave spring while you are in there if you have the weak one - they are notorious for failing. Seen photos where this has broken and jammed in the oil pump - http://www.transmissiondigest.com/tech/TD200508/200508ShiftPointers/200508ShiftPointers.htm

[Kryton]

Awesome, I will keep you posted once mines out to see what exactly has gone. I don't understand most of this tbh but the man doing it will (I hope /haz)