Gearbox alternate oil type needed please

[snake_bitten]

Ok I am using the Tremmec recomended oil Dextron 3 and this seems ok when cold, but the gearbox gets noisy when everything heats up, new gearbox.

I have a friend who works for the company doing the noise testing on tremmec for Ford US, and he says that they are all noisy to greater or lesser degrees but are prety bullet proof, and that ford get the best ones of the line and everyone else just has to take pot luck.

So I will not be changing the gearbox but would like to change the oil for a slightly thicker one that is compatable with the box.

ATF is pretty thin stuff, so my thought is that any good motor racing box oil should be ok, after all it is just gears in there

Anyone able to advise please??

[wilf]

I think that if you move away form the recommended stuff, you will start having synchro problems. There is a Royal Purple synthetic oil that has been recommended here by Dr Dee I believe - try a search on "royal Purple" to get the details.

Might just have to put up with the noise..........how do you hear it above the V8 anyway?

[Sidecarbod]

I had problems with the my LT77 box and spent quite alot of money on varrious types of oil. Most of them made a smooth gearchange impossible when the oil was cold.

I then tried Redline MTL and can say the change was remarkable!.

I believe others have had similar experiances.

If you do decide to try it be careful as there is a similar product called heavy shock oil (or something like that!)

If the gumph on redlines' website is to be believed it does make interesting reading.

Here's a link:-

http://www.redlineoil.com/products_g...p?categoryID=7

(Open the Tech info PDF)

Regards,

Pete

[dave]

Wilf.
He has a hard top, this doesn't help at all when it comes to transmission noise. Think "Days of Thunder" (The Tom Cruise NASCAR movie).

[Cobra289]

RED LINE advises as substitute for the Dexron III the next:

HIGH-TEMP ATF - synthetic ATF for use where Dexron
III or Mercon is recommended. A higher viscosity allows
optimal operation at 70°F higher temperature, providing
better torque converter efficiency. Provides wear protection
of a GL-4 gear oil. Perfect for heavily-loaded vehicles
and automatic transaxles. Superior stability allows
high-temperature operation without varnishing valves
and clutches which causes failure. Provides the same
low-temperature operation as with a conventional ATF.

I stay by the recommended GM #12345349

TREMEC DOC's
Oil
Caution: NO OIL IN TRANSMISSION. Due to various synchronizer materials used in TREMEC
transmissions, and different climates and applications, no one single fluid will work for all transmissions. We
recommend GM synchromesh part # 12345349, or Dexron III / Mercon Spec ATF fluid for all TKO
transmissions. The transmission should be filled through the fill plug located on the passenger side of the
transmission. Proper fill level is achieved when oil reaches the fill plughole when level (approximately 5.28
pints)

I hope this help!
Cobra289

[wilf]

Originally Posted by dave

Wilf.
He has a hard top, this doesn't help at all when it comes to transmission noise. Think "Days of Thunder" (The Tom Cruise NASCAR movie).

Then I am surprised he can hear it over the diff noise! LOL

[snake_bitten]

Originally Posted by wilf

Then I am surprised he can hear it over the diff noise! LOL

Wif,
Thanks for the reply.
Dave beat me to it, yes more noticable with the top on.....Diff noise???? can't hear that for the drive shafts clunking.

The disconcerting noise that prompted my post is mainly when stopped and in neutral, If I dip the clutch it goes away but it is only there when every thing is up to temp. Also I can make it louder or quieter by moving the selector.

[Cobra289]

Hi Snake_bitten,
I have look to your garage and it looks like you are a daily Cobra driver, so you know every small sound or noise of the car very well.

The disconcerting noise that prompted my post is mainly when stopped and in neutral, If I dip the clutch it goes away but it is only there when every thing is up to temp. Also I can make it louder or quieter by moving the selector.

Based on this information I would say that something is going on at the input shaft or components of this shaft.
- Throughout bearing (less probable) because noise goes when you press it.
- Bellhousing out of alignment or a bit loose bolts. Probable due that it forces the input shaft bearing to be inclined and when you depress the clutch there is no movement at this bearing.
- Input shaft bearing (front bearing) Probable it has goat extra play, need to have a larger shim. Desired end plat at the input shaft is 0.000 to 0.004 inch.
- Loose bolts from transmission to Bellhousing. Probable, that can make your input shaft to be inclined and more when it is hot.
- Low oil level. Probable but I think that you all ready have inspected that.
- Wrong oil. Very probable, not that is wrong but that has lost the initial lubrication quality.

I would start by changing the oil and look for the best that you can get. Check and re-check the oil level, too much and the gearbox will leak a couple of drips, but……….. if that helps….
Check all the fixing bolts, Bellhousing to engine and box to Bellhousing.
If this doesn’t help the next step would be check the input shaft end play, move box a bit backwards if that is possible in a DAX of 2008, check with your fingers at the shaft and if you have movements, plan to remove the front bearing retainer (4 bolts) and remove the end play.
It can be done in the car but with a lot of cursing.

I hope that this help, please let us know the results, it is to interesting to know it.

Regards,
Cobra289

[wilf]

John - what you are hearing is the backlash in the box being taken up in either direction by the relatively slowly-happening firing impulses of the V8 at tickover. You could make it go away or recuce by increasing the tickover - try it. In reality they pretty much all do it - at a standstill, I can make out the same noises as you from my tremec, even without a hardtop, so maybe just learn to live with it and accept it as part of the music your car generates.

[snake_bitten]

Originally Posted by wilf

John - what you are hearing is the backlash in the box being taken up in either direction by the relatively slowly-happening firing impulses of the V8 at tickover. You could make it go away or recuce by increasing the tickover - try it. In reality they pretty much all do it - at a standstill, I can make out the same noises as you from my tremec, even without a hardtop, so maybe just learn to live with it and accept it as part of the music your car generates.

Thanks Wilf,

Just returned from the garage, I have hopefully eliminated the drive shaft clunking. Masive amount of play between the DiDeon inner CV/driveshaft splines so I have just introduced the splines to Loctite 603.

All being well, one less noise. Also found Gbox touching bolt head on chassis, that is not going to help.