JCFsupra

I'm trying to hit 700 rwhp and bought a built TH400. There was a pretty bad vibration at start up so we checked alot of things trying to find the culprit.

Took it to a trans shop and they opened up the trans and suggested that we have them do this:


Cleaning-suggest hot tanking entire unit.
Overhaul kit with rings (teflon) and seals.
Differant direct friction & steels & clearance corrected.
Thick snap ring on intermediate clutch
Bearing in place of thrust washer on output shaft to case.
Proper clutch clearances set
Cushion in Forward drum
Proper filter hardware (bolt & spacer)
All new bushings, bearings & thrust washers.
Stronger clutch hub?
Restrictor in pump? (Turbo cars only)
New pump body & Gears
Snap ring secured on direct drum
New bolts holding on bellhousing.
Valve body gaskets.
Modify govoner for higher rpm upshifts?
Drum Springs?
New wider hd int band
New Low rev band?

It was checked over and upgraded by a shop in Virginia that is very respected and suddenly this shop found issues. Any thoughts on what's happening? Is this normal or is the new shop going overboard?

Any help from experienced TH400 racers would be appreciated. Thanks

Gilbert@Ace Racing

I do not see anything in that list that addresses a vibration. Did you ask them which of those issues will solve your problem? I do not doubt that the upgrades they listed will help you in the long run... not sure about everything listed, but I don't know your combination or goals well enough to make determinations either.

My point is, if the TH400 you bought does not have roller bearings installed at the very least, I would be concerned that it can hold up to serious duty. But, I say that knowing nothing about it other than the recommended upgrades that someone else listed.

Here's what I suggest you do... decide which shop you're going to go with. Put your full faith and trust in them. If you cannot do that, you are dealing with the wrong shop in the first place. What did the original builder say when you called them about the vibration?

I know it's hard understanding who to believe and understand, but in my opinion you are looking for a long term relationship...not just a transmission builder that can handle the power you are capable of putting down with your budget. That builder will understand your program and care enough to help you through the highs and lows from now on. He won't be there to just build today's transmission... but will be there to build all the transmissions you'll need for many years to come.

Do not hesitate to call me to discuss your issues in detail. I don't have a dog in this hunt and can give you solid advice without an opinionated answer. We can cover much more ground in 15 minutes than we can in conversation here on the forums buddy! Hope all that helps....

g

JCFsupra

Gilbert thanks for the info. When I spoke with the original trans shop guy who looked the trans over and made it race ready for the previous owner it seems did the build or bought it built, and told him what this new place said, he said that it was as if they wanted to build me an entirely new trans and probably get $2k out of me. That shocked me but now hearing that none of the recommendations address the vibration issue I'm starting to think that I might be getting set up again.

I've spent way too much on the car as it is. The vibration in my opinion was either the TC or the adapter plate. The TC was sent back to Illinois to the shop that it was bought at and they had their builder from WI pick it up and look it over. It turned out that the TC was shipped out without being balanced the first time. Now it was balanced and a new bushing installed.

Upon reinstalling the TC & trans the vibration was still there just not as bad. The trans was mated to an SP adapter plate and the jz bellhousing a popular 2JZ-GTE Toyota Supra upgrade for hi hp MK3 supras that need to be able to hold the power. The first guy said that the bellhousing and adapter had issue not fitting together properly but then never did anything to correct it just mentioned it to the previous owner.

This new shop seems to mention that they need attention which made me think that they were doing things right but if you say that that doesn't affect the vibration either then I don't know what to think. I just figured that if anything was off a mm or two that that would be where the vibration came from. To say that it didn't sit flat triggered a red flag with me. I omitted this part of a paragraph which may help...
First off, the bolts that hold the bell housing on need to be replaced.
The bellhousing is not sitting flat on the pump-Case needs to be cut down more.
The pump assy has some wear on the cresent and the pump gears (inner) show
signs of wear on the inside where the converter rides. The pump washer has a steel
shim installed under the plastic washer. Pump has no cooler restrictors.

JWStevens

iTrader: (1)

Did you disconnect the converter and crank it without spinning the trans when you were diagnosing the problem?

Jake's Performance

iTrader: (2)

If it uses an "Ultrabell" style bellhousing, and it's hitting the case, that will make the trans sit out of line with the engine crankshaft, possibly causing a vibration and definitely converter hub/pump bushing wear.


Otherwise, internally in the transmission there isn't much that can usually cause a vibration. The major components are balanced from the OEM and unless you do some major machining, no rebalancing is required during a rebuild.

Usually the out of balance will be traced back to the torque converter if a trans swap was done and caused the imbalance.

Unfortunately it is hard to determine if a transmission shop is an honest one or not. Lots of scam artists out there and sometimes they have very good methods to protect their reputation.

JCFsupra

JWStevens - Yes and the vibration went away.

Jake - it's a Toyota Supra 2jz stock bellhousing and not being familiar with the term I looked it up and read a little about it on the Jegs website. I don't think it is.

JWStevens

iTrader: (1)

Just checking! Good luck