Frequently Asked Questions Quality Transmission Service, Tempe, Ariz

35- Can I replace my GM overdrive transmission in my 4x4 with a 3 speed unit?

Yes, it is possible, but not practical in my opinion.

The job is a major redesign of the drive train.

• Both drivelines have to be modified
• The crossmember support position has to be changed
• There's the cost of the 350/400 transmission to purchase for the swap
• The filler tube/dipstick has to be changed
• The adapter to the transfer unit for the 700 will not fit the 400, it will for the 350
• The output shaft of the 400 will be expensive since 700 output shaft has a smaller diameter, and the 350 will need a different length shaft
• An electrical kickdown switch has to be installed for the 400
• The throttle valve cable will have to be replaced with a kickdown cable for the 350

Also the gear ratios are different for 1st, 2nd, and reverse, so the takeoff will be less efficient.

	350 / 400	700
1st gear	2.48 : 1	3.06 : 1
2nd gear	1.48 : 1	1.62 : 1
3rd gear	1 : 1	1 : 1
Overdrive	none	1 : 1.30
Reverse	1.93 : 1	2.29 : 1

With no overdrive, the engine rpm's will be higher at highway speeds (same as 3rd gear with the 700) and the gas mileage will be less.

In late model, computer controlled applications, the electrical system will need to be modified since the normal feedback to the computer will not be available with the 350/400.

Other than that, the 350/400 are good units, but the 700 can be built to hold up. 

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36- What is your opinion about transmission additives?

For the most part, I'm not a fan of additives.  Most of them have compounds that voraciously attack the "rubber" seals throughout the transmission.  Usually, only a portion of the seals have hardened due to heat and age, but the additives will not be able to differentiate between the ones that are hard and the ones that aren't.

Therefore, when the additives come in contact with the seals, they swell and soften to a point that they will not function.  The common experience after using the additive is a betterment initially, but after a few weeks, there is a major deterioration in the performance of the unit.  If the seals are damaged, there is no improvement, just the deterioration phase.

With external leaks, the additive will not cure gaps , such as loose pump bolts, worn bushings, cracks in the case, bad gaskets, etc.

I've seen more harm than good from the use of such products, and am a firm believer in periodic service as the best for the health of the unit.

The only one that we will use is called "Lubegard," and is used primarily the cure minor valve body hang-ups and torque converter clutch chatter.  

www.lubegard.com/

If all those additives for sale did as much as they promise, we would not be in business!

Also, usually the slickest thing about the additive is the person selling it!
 

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37- Is this repair a guess or a fix?

When a repair is recommended and you don't necessarily feel that the result will remedy the problem, ask the service writer if this is a guess or a fix.  If the answer is a guess, ask whose money are we guessing with, theirs or yours.

There are times that an "educated guess" is recommended to resolve a problem, and the results do not fix the problem.  This usually creates several emotional reactions such as:

• I've been taken!

• I just wasted my time and money.

• These guys don't have a clue.

This might have been avoided if this subject was covered before the repair was started.

As a consumer, you need to feel that you made the decision to proceed with a repair based on the knowledge that the recommended repair was appropriate and was going to remedy the problem.  If there was any doubt, you should have been told that this may not fix the problem.  Then you should evaluate the risk before you give the authorization to proceed.

Remember, it's your money and time that is at risk.  You should feel comfortable that the recommended repair will provide the correct result.  If not, get a second opinion.

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38- The estimate includes "soft parts" but not "hard parts.
What's the difference?

Soft parts include clutches, bands, overhauls kit, filter, internal sealing rings, bushings, external seals and gaskets.  These are the parts, along with a torque converter, that are always replaced during an overhaul of a transmission.

Upon internal inspection, some major component parts may also need to be replaced such as the pump, a clutch drum, or a planetary gear set.  There's no way to know the condition of these "hard parts" before the unit is disassembled in order to include them in an estimate.

In the "old days" the cost of these parts was minimal due to the limited variety of transmissions and could be included in the estimate, however late model, computer controlled unit can have some expensive parts that may need to be replace to insure that the unit is fully repaired.

So, it is common for a major repair of a transmission to include a list of the commonly replaced parts, and remain open until an internal inspection of the unit can be made.

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