Transmission woes

[qube_TA]

Hi,

I've been recommended to post on here regarding my problem.

I have a 1988 Trans Am with the 305 TPI V8 engine and the 3-speed + OD TH700R4 transmission.

Due to a suspected oil circulation problem the transmission overheated, dumped its' contents and now 3rd gear slips.

I'm looking to either get the box fixed or replace it so was looking to find someone that could help.

A reconditioned box from the US is about $600 + freight & tax and around £200 to have fitted.

The quotes I've had for fixing the exiting one are around £1600

Not been able to source a good s/h box from a breaker either.


Any thoughts or advice is appreciated.

[MotorPsycho]

I would imagine this is one for Andy Frost (Redvictor) sure he'll be along soon!

[redvictor]

Fixing them properly here costs a lot more than $600 i'm afraid. Fixing it so it lasts will be £1500 from me..

[chevy-stu]

$600 + shipping (and 10% import duty + 15% vat of course) and £200 fitting sounds cheap to me.. There's a alot of shoddy rebuilds around for these too from what I've heard..
I'd think keep searching all the US specialist garages and breakers for a s/h one if I were you, or bite the bullet and get yours rebuilt..

[qube_TA]

is that + VAT?

Shipping quotes so far have been about $700 so the rebuild might still be the cheaper option.

[KP1]

It´s pretty common that the 3-4 clutch burns in these trannys. I buy thinner frictions and steel and put in 8 frictions instead of the 6 that are there from the begining. I know that they put in 9 frictions but then you have to use a very thin endplate.Pluggin the 3-4 accumulator helps also + a couple of other things...
I rebuild them and make them stronger for £900 but I´m probably stupid...

[redvictor]

KP1 said:

It´s pretty common that the 3-4 clutch burns in these trannys. I buy thinner frictions and steel and put in 8 frictions instead of the 6 that are there from the begining. I know that they put in 9 frictions but then you have to use a very thin endplate.Pluggin the 3-4 accumulator helps also + a couple of other things...
I rebuild them and make them stronger for £900 but I´m probably stupid...

Of course the shipping back and forth to Sweden might be a little bit of money..

[redvictor]

qube_TA said:

is that + VAT?

Shipping quotes so far have been about $700 so the rebuild might still be the cheaper option.

Yes,plus VAT.

[qube_TA]

Cool, might be giving you a shout to discuss, one the problems is getting the car to you from Leeds.

[redvictor]

qube_TA said:

Cool, might be giving you a shout to discuss, one the problems is getting the car to you from Leeds.

are you in the AA or RAC?

[eliot]

KP1 said:

It´s pretty common that the 3-4 clutch burns in these trannys. I buy thinner frictions and steel and put in 8 frictions instead of the 6 that are there from the begining. I know that they put in 9 frictions but then you have to use a very thin endplate.Pluggin the 3-4 accumulator helps also + a couple of other things...
I rebuild them and make them stronger for £900 but I´m probably stupid...

I've tried (and killed) many of the aftermarket 3/4 clutch packs. As you note, the 9 plate setups are too thin. The Alto 8 plate set with full thickness steels was better but still died after less than 2k miles.
This is the setup:

I believe the lowest pressure plate warped due to the extra clamping pressure, which then burned the whole thing up:

Notice how its the outsides of the plates that are burned:


I replaced that clutch pack with the Raybestos "Z pack" - which notably comes with a decent thick first pressure plate - this has now been in the car trouble free for a couple of years.

How much you spend on a rebuild depends on how much torque, weight and traction you intend to put through the box. I spent around £1500 on the parts alone inside my current box, but that does include OEM GM 5 pin planet gears and a torque drive input drum - which for a mild setup is un-nessesary imo.

My reccomendations:
Post 1987 Core
Raybestos Z-pack 3/4 pack *
Carbon STD Width Band 2-4 Band (instead of Kevlar extra wide)*
Transgo Separator Plate *
Pinless Accumulator Pistons
Stronger Accumulator springs
.500 Boost valve *
Bigger low/reverse valve
Elevated Pump PR spring *
Stronger TV spring *
Beast sunshell
29 element sprag

• these parts should go into every build IMO - they are cheap and make a big difference.

Performance torque Convertor
Superior Super 2 & 4 servos
New bushes,bearings & washers

Then these parts if you are really beating on it with weight/power:

TDE Torque Drive Drum and Shell with hardened input shaft
Genuine GM Front 5 Pinion Planetary
Genuine GM Rear 5 Pinion Planetary

Edited by eliot on Saturday 8th August 09:44

[veryoldfart]

redvictor said:

KP1 said:

It´s pretty common that the 3-4 clutch burns in these trannys. I buy thinner frictions and steel and put in 8 frictions instead of the 6 that are there from the begining. I know that they put in 9 frictions but then you have to use a very thin endplate.Pluggin the 3-4 accumulator helps also + a couple of other things...
I rebuild them and make them stronger for £900 but I´m probably stupid...

Of course the shipping back and forth to Sweden might be a little bit of money..

ask me for a price.... you may be suprised!

Edited by veryoldfart on Saturday 8th August 16:33

[KP1]

For a 305 engine in a Camaro I think you don´t need all the fancy stuff. Modify the 3-4 clutch and a little drilling and pluggin.I have done some and they works fine.
I recently did one 700 with the fancy stuff for my friends 32 Ford with a 598" engine and four link setup. I did some "funny things" in that tranny and told him to test it and then call me because I am not sure if it works. He called me and said it shifted really strong to second but when he shifted to third at 90 mph it brooked loss rear tires and the car was slipping all over the road. I liked that! Limited lifetime I guess but works fine so far. It´s fun to do some weird things and then try it in the car. Hopefully I can learn me something on it also.

[eliot]

KP1 said:

For a 305 engine in a Camaro I think you don´t need all the fancy stuff. Modify the 3-4 clutch and a little drilling and pluggin.I have done some and they works fine.

Indeed - but I would still select the Z-pack though - its only $72.

[steve y]

veryoldfart said:

redvictor said:

KP1 said:

It´s pretty common that the 3-4 clutch burns in these trannys. I buy thinner frictions and steel and put in 8 frictions instead of the 6 that are there from the begining. I know that they put in 9 frictions but then you have to use a very thin endplate.Pluggin the 3-4 accumulator helps also + a couple of other things...
I rebuild them and make them stronger for £900 but I´m probably stupid...

Of course the shipping back and forth to Sweden might be a little bit of money..

ask me for a price.... you may be suprised! no, not surprised just staggered that you may finally have a useful conrtibution to this forum rather than stupid glib comments!
Steve

Edited by veryoldfart on Saturday 8th August 16:33

[SVTRick]

I think your money should be on the guy with that Red Vauxhall

If he builds his own transmission for that car, or at least builds his own race car to run those numbers then your quest is answered in full.
I am sure he runs his own transmission shop so you have some kind of back up as it's UK based.

I had my Lighting Transmission built in the States and shipped over.
And cost about the same as you have been quoted plus shiping.
This was after a well known Sussex based company wanted to upgrade my existing one with Mustang parts for more money... WTF
JDM supplied me a BTS Transmission (ok I stumped up for the core charge as it was too expensive to ship mine back) but the BTS unit will handle well in excess of 700 RWHP and has proved itself over 3 years of road use and many 1/4 mile passes.

SIMPLES

[Tet]

veryoldfart said:

redvictor said:

Of course the shipping back and forth to Sweden might be a little bit of money..

ask me for a price.... you may be suprised!

OK, then, I'm asking. Since I happen to have a dead TH350 right now, how much to ship it from London to Sweden and back to have Krister fix it?

[It's fixable...]

Tet,

Surface freight is not that expensive, but airfreight will hurt. It's all about time and how much you have...

Any freight forwarder can arrange this shipment for you and you'll find plenty of them in your local Yellow Pages, or support a racer and use Malcolm Francis' company.

To give you a price they will need the outside dimensions of the package given in centimetres and the nett (item inside the box) and gross (item inside the box + the box) weights given in kilos, plus the full destination address and postal or zip code.

You will need to address the box (obvious) and attach a shipping note (stating "Goods in free circulatuion") that includes the value of the unit.

Drop me a mail if you want some help...

[qube_TA]

air-freight for a box from the US to UK was going to be $700, by boat was $300 if anyone is interested.

a pre-built reconditioned box was between $600 and $900 depending upon the power you wanted to put through it.

I've seen a box on Ebay which I'm going to buy for mine as the car isn't really worth dropping the best part of £2K on for this as it also has engine issues.

[PhilSweeney]

Or try Ian Malcom at Apsley Tranmissions, Ian's wife Liz, drives their rear engine dragster in Pro ET, very knowledgeable guy.